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August 29th, 2022

Wrong Cartridge in Chamber — What Can Happen

Ruptured Cartridge Case

If you don’t match your ammo to your chamber, bad things can happen, that’s for sure. A while back, Forum member BigBlack had an experience at the gun range that reminds us of the importance of safety when shooting. He encountered evidence that someone had fired the wrong cartridge in a 7mm WSM rifle. The problem is more common than you may think. This Editor has personally seen novices try to shoot 9mm ammo in 40 S&W pistols. BigBlack’s story is along those lines, though the results were much more dramatic. It’s too bad a knowledgeable shooter was not nearby to “intervene” before this fellow chambered the wrong ammo.

7mm-08 is Not the Same as a 7mm WSM
BigBlack writes: “I know this has probably been replayed a thousand times but I feel we can never be reminded enough about safety. This weekend at the range I found a ruptured case on the ground. My immediate thoughts were that it was a hot load, but the neck area was begging for me to take a closer look, so I did. I took home the exploded case and rummaged through my old cases until I found a close match. From my investigative work it appears someone shot a 7mm-08 in a 7mm WSM. Take a look. In the above photo I’ve put together a 7mm WSM case (top), the ruptured case (middle), and a 7mm-08 case (bottom).”

The photo reveals what probably happened to the 7mm-08 case. The shoulder moved forward to match the 7mm WSM profile. The sidewalls of the case expanded outward in the much larger 7mm WSM chamber until they lacked the strength to contain the charge, and then the case sides ruptured catastrophically. A blow-out of this kind can be very dangerous, as the expanding gasses may not be completely contained within the action.

Can’t Happen to You? Think Again.
This kind of mistake — chambering the wrong cartridge — can happen to any shooter who is distracted, who places even a single wrong round in an ammo box, or who has two types of ammo on the bench. One of our Forum members was testing two different rifles recently and he picked up the wrong cartridge from the bench. As a result, he fired a .30-06 round in a .300 Win Mag chamber, and the case blew out. Here is his story:

“I took two of my hunting rifles I have not used for over 25 years to the range yesterday to get new scopes on paper, a .30-06 and .300 Win Mag. I had four boxes of old Winchester factory ammo (two of each cartridge), which had near identical appearances. I accidentally chambered a .30-06 round in the Sako .300 Win Mag rifle. It sprayed powder on my face and cracked the stock at the pistol grip. If I had not been wearing safety glasses I might be blind right now.

Safety eyewear glasses
You should always wear protective eyewear, EVERY time you shoot.

“I feel lucky and am very thankful for being OK — other than my face looks funny right now. I am also grateful for learning a valuable lesson. I will never put two different cartridges on the bench at the same time again.”

READ More about this incident in our Shooters’ Forum.

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August 7th, 2022

Protect Yourself — Check for Possible Brass Case Wall Failure

cartridge case separation

We are re-publishing this article at the request of Forum members who found the information very valuable. If you haven’t read this Safety Tip before, take a moment to learn how you can inspect your fired brass to determine if there may be a potential for case separation. A case separation can be dangerous, potentially causing serious injury.

cartridge case separationOn the highly-respected Riflemans’ Journal blog, created by our late dear friend German Salazar*, there was an excellent article about Cartridge Case-Head Separation. In this important article, Salazar (aka GS Arizona) examined the causes of this serious problem and explained the ways you can inspect your brass to minimize the risk of a case-head separation. As cases get fired multiple times and then resized during reloading, the cases can stretch. Typically, there is a point in the lower section of the case where the case-walls thin out. This is your “danger zone” and you need to watch for tell-tale signs of weakening.

The photo below shows a case sectioned so that you can see where the case wall becomes thinner near the web. You can see a little arrow into the soot inside the case pointing to the thinned area. This case hadn’t split yet, but it most likely would do so after one or two more firings.

cartridge case separation

Paper Clip Hack for Detecting Problems
The article provided a great, easy tip for detecting potential problems. You can use a bent paper clip to detect potential case wall problems. Slide the paper clip inside your case to check for thin spots. GS Arizona explains: “This simple little tool (bent paper clip) will let you check the inside of cases before you reload them. The thin spot will be immediately apparent as you run the clip up the inside of the case. If you’re seeing a shiny line on the outside and the clip is really hitting a thin spot inside, it’s time to retire the case. If you do this every time you reload, on at least 15% of your cases, you’ll develop a good feel for what the thin spot feels like and how it gets worse as the case is reloaded more times. And if you’re loading the night before a match and feel pressured for time — don’t skip this step!”


* Sadly, German Salazar passed away unexpectedly on June 21, 2022 at age 62. German was a great inspiration to this site and help guide the creation of the AccurateShooter Forum. A brilliant man, expert attorney, and top-tier marksman, German will be sorely missed in the shooting sports world. We plan a more lengthy In Memoriam tribute to German in the weeks ahead.

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July 19th, 2022

Long-Term Powder Storage — What You Need to Know

Western Powders Blog SAAMI Storage

SUMMARY: Powder can have a very long shelf life. You need to watch for changes in smell and color. A reddish tinge, almost like rust on the powder, is a bad sign, as is a foul odor, not to be confused with a normal chemical smell. Either of these signs indicate it is time to dispose of your powder by means other than shooting.

Ever wondered about the stability of the propellants in your reloading room? There are some important things you should know about powder storage, to ensure consistent powder performance and safety. Western Powders (which has been acquired by Hodgdon) published an informative Q & A series entitled Dear Labby: Questions for our Ballistics Lab . Here are some excerpts that pertain to powder storage and shelf life. Worried that your powder may be too old? Western’s experts explain how to check your propellants for warning signs.

Proper Powder Storage

Q: I live in southern Arizona where it is very hot. I am told powders will become unstable if stored in an area not air-conditioned. My wife says no powder or primers in the house. Can powder be stored in a refrigerator? What about using a fireproof safe? I would appreciate your ideas. — M.C.

Lab Answer: SAAMI guidelines are pretty clear on issues of storage. They recommend storing smokeless powder in containers that will not allow pressure to build if the powder is ignited — ruling out gun safes and refrigerators.

CLICK HERE to Read SAAMI Guidelines for Powder Storage (PDF)

In their original containers, the lifespan of smokeless powders is quite long, even in hot, arid climates. In fact the lifespan is typically longer than the average handloader would need to store them. Stored safely in a garage or outbuilding, your powder should last years. If you see the powder developing a reddish tint, or giving off a foul odor, it is time to discard it.

Clumps in Powder Container

Q: I ordered some of your Accurate 1680 powder back about in December. I just now opened it … and it is full of clumps. My knowledge tells me that means moisture. Am I wrong? I just now broke the seal and it has been stored in a ammo can with desiccant packs around it and a dehumidifier running 14-16 hours a day. I can’t imagine this being my fault, if this does indicate moisture. I don’t know if the pink part on the label is suppose to be red or not, but it is definitely pink, so if it was red I am wondering if I was shipped an old container? I hope that this isn’t bad and I am stuck with it…

Lab Answer: All powder contains a certain amount of moisture. When the powder is stored or during shipping, it can go through temperature cycles. During the cycling, the moisture can be pulled to the surface and cause clumping. Clumping can also be caused by static electricity if too dry or the powder has limited graphite content. You can break up the clumps before metering and they shouldn’t be a problem. This will not affect the powder performance, so your product is fine. Accurate 1680 labels are designed in Pink. As a side note, specification for testing powder is at 70° F and 60% humidity.

Shelf Life and Packaging Dates

Q: Does powder ever get to old to use and what identifying marks does your company put on the canister for when it is made, You have helped me out a while ago when I asked about keeping my cowboy shooting under 950 fps and it works great less stress on the hand and the recoil is very minimum. — R.B.

Lab Answer: On one pound bottles, the number is on the corner in a silver box. If the powder was poured today, it would read 012815 followed by a lot number. The whole number would look something like 012815749. Eight pound bottles have a sticker on the bottom with an obvious date code. The lot number appears above the date.

Western Powders Blog SAAMI Storage

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May 10th, 2022

Beware Barrel Bore Obstructions — These Can Cause Blow-Ups

Obstructed Barrel Explosion Accident kaboom
Above is a sectioned barrel showing an 80gr Sierra that was fired in a .223 bolt action with a cleaning rod in the bore. Both the bullet and the rod are still in the bore.

A Negligent Shooter Gets Lucky
“Here we have a story so filled with negligent acts that I can only marvel that the shooter survived the experience. The photo and narrative were provided by the gunsmith who took in the repair job, my comments are in italics. It’s worth reading, we can’t get enough safety warnings in our hobby.” — GS Arizona, Rifleman’s Journal

Description of Incident (with Commentary)
The shooter had a stuck case in his .223 chamber. The stuck case was actually a loaded round that didn’t fire. It wouldn’t extract because it was a .222 case that got mixed in with his .223 brass. [He had loaded the wrong brass.] I saw the loaded round with an 80gr bullet in it and a light primer strike. Negligent Act #1: Wrong brass was mixed in with the brass being reloaded.

The shooter removed the stuck case with a 3-piece aluminum rod. Negligent Act #2: Hammering out a loaded round with a cleaning rod. People have been killed doing this as the round can fire and drive the cleaning rod right into you. I remember one such incident about 5 years ago, the shooter was pounding out a stuck round, the cleaning rod went right through him, he didn’t survive.

The shooter didn’t notice only two segments of the cleaning rod came out when he removed it. Negligent Act #3: If you put anything at all down the barrel of a rifle you’d better make darn sure you got it all out before doing anything else!

He then chambered another round and fired it. Negligent act #4: If you’ve had a barrel obstruction of any kind, and if you’ve put something in the barrel, look through the barrel before proceeding! Within the past two years I know of an incident in which a benchrest shooter was killed in exactly this manner. The pressure built up and the rifle bolt came out of the receiver and into his chest.

The shooter is ‘OK’, but did not escape unscathed. He said there was a huge explosion and after regaining his senses found he was bleeding heavily from his forehead. The blood was thick enough that it ran in his eyes and he couldn’t see. In his words “I thought I was going to die”.

He has what looks like a pretty deep cut about an inch long on the side of his head, right in line with his right eye starting where the eye socket turns out to the side of the skull. And no telling what he’s got in the way of brass particles embedded in his forehead.

He was shooting on private property, and was alone when this happened. Negligent Act #5: Don’t shoot alone! Accidents happen, this is just one more example. If we could predict accidents, we wouldn’t have them. Always shoot with at least one other person.

He managed to get the bleeding stopped, or at least under control, packed his car and drove himself home without seeking immediate medical attention. Negligent Act #6: This one could have cost him his life after being lucky enough to survive the incident. There’s no way to know what’s happened just after an incident like this. He should have been at a hospital getting checked for shrapnel in the head.

The rod and slug could not be driven out. Since the barrel had a high round count there was no point in trying to salvage it. Note that the aluminum rod is expanded to a tight fit in the bore for the first couple inches. The base of the bullet is a little over 2″ from the mouth of the chamber.

What we’ve seen here is negligence and an absolute indifference to the established rules of safe reloading and gun handling, from start to finish, capped off with the shooter’s foolish avoidance of medical treatment. This shooter is lucky to be alive, but he’s surely used up all his luck. Don’t assume you’ll be so fortunate.

This article originally appeared in the Rifleman’s Journal website, which is no longer available.

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April 28th, 2022

Cleaning Rod in Barrel Caused Catastrophic .338 LM Kaboom

Kaboom Manatee Savage .338 LM, Lapua Magnum, catastrophic, explosion, cleaning rod, obstruction
CLICK HERE to zoom image.

We first ran this story a few years back. We’re republishing it today as a reminder to our readers that safety should be their paramount concern at the range. Avoid distractions and always check your barrel for obstructions before you chamber a round or pull the trigger. A moment of inattention can result in a catastrophic kaboom.

Discharging a .338 Lapua Magnum round with a cleaning rod in the barrel — that’s a recipe for disaster. What happens when a fired .338 caliber bullet and a cleaning rod try to occupy the same place at the same time? Well you get a catastrophic kaboom, with metal pieces flying all over the place, and a shooter very lucky to escape without serious injury. This incident occurred recently in Manatee, Florida, as reported by Sniper’s Hide member Queequeg. We thank SnipersHide.com for granting permission to publish these revealing images in the Daily Bulletin. CLICK HERE for more Kaboom info from the ‘Hide.

Kaboom Manatee Savage .338 LM, Lapua Magnum, catastrophic, explosion, cleaning rod, obstruction
This story should serve as a chilling reminder to follow proper safety practices whenever you are at the range. Always check to make sure there is no obstruction in the bore BEFORE loading a live round.

.338 Lapua Magnum + Cleaning Rod + Inattention = Kaboom!

Kaboom at Manatee!
Sniper’s Hide member Queequeg recently published shocking photos of a catastrophic kaboom involving a .338 Lapua Magnum (Savage action). The action was blown off the rifle, shrapnel went through the roof, and the barrel split at the tenon before taking an excursion downrange. The action did crack in the front but the lugs remained engaged so the bolt did not slam to the rear (luckily for the shooter).

Here’s the report: “This happened [January 20, 2014] at the Manatee Gun and Archery Club. Al, Ren and myself were there with a couple other folks. Ren was at bench 12, I was at 13. The fellow at 11 was running a Savage .338 Lapua. He had a very bad day! He damn sure could have killed himself and quite likely Ren as well.”

Kaboom Manatee Savage .338 LM, Lapua Magnum, catastrophic, explosion, cleaning rod, obstruction

Queeqeg added: “After the boom, I heard Ren ask ‘Are you alright’ and then turned to look in time to see the fellow reacting in total shock — literally stunned. Ren and I went over to him and could not see any major injuries. Ren was uninjured as well but had a lot of fiberglass splinters on him. The barrel nut is what I presume punched the two holes in the roof. The shooter is a regular there[.] He had been having a problem with sticky cases though he said he was certain the loads were mild. That’s why he was content to knock the sticky ones out with the rod. He simply forgot to remove the rod after knocking out the last stuck case. You can see what happened next.”

Kaboom Manatee Savage .338 LM, Lapua Magnum, catastrophic, explosion, cleaning rod, obstruction

Kaboom Manatee Savage .338 LM, Lapua Magnum, catastrophic, explosion, cleaning rod, obstruction

Kaboom Manatee Savage .338 LM, Lapua Magnum, catastrophic, explosion, cleaning rod, obstruction

Kaboom Manatee Savage .338 LM, Lapua Magnum, catastrophic, explosion, cleaning rod, obstruction

To learn more about this incident, go to the original Snipers Hide Forum Thread. There you’ll find more details and four pages of related discussions.

The Important Lesson Here
What did the .338 LM shooter do wrong here? You will say — “Well that’s obvious, he left a cleaning rod in the barrel and then shot a round.” Yes, that was a potentially fatal error. But that was his second mistake — one that occurred only because he made a more fundamental judgment error first.

The FIRST mistake was not acknowledging the problem with his ammo. Had he heeded the warning signs, he would still have a rifle (and an unsoiled pair of trousers). When he first observed that he was having problems with extracting cases, a warning light should have gone off in his head. Presuming his extractor was not broken (and that the chamber was cut properly) he should have been able to extract his brass if he was running safe loads. The lesson here we all need to learn is that if you observe a serious ammo-related issue, it is time to stop shooting. Don’t try to invent work-arounds just to extend your range session, when there are clear signs that something is wrong, very wrong.

Permalink Competition, Shooting Skills, Tech Tip 4 Comments »
April 8th, 2022

Pre-Season Rifle Maintenance Checks — Get Your Rifles Ready

Spring pre-season gun maintenance safety

We are a week into April. That means the spring shooting season is underway in most parts of the country. Before you head to the range for the first time, we recommend you do some basic tasks with your firearms. Here’s some good advice on readying your rifles for the 2022 shooting season.

by Ron Dague, Sinclair International
Firearms SafetyI give my rifles a pre-season check before the shooting season starts. This starts with a general inspection starting with the butt-plate or recoil pad and making sure that all the screws and adjustable parts (on an adjustable butt-plate) move freely up or down and side to side. If you got caught in rain some of these screws and adjustable parts may not move when needed. I disassemble parts as needed and put rust preventative or a light oil and/or grease on threads and sliding parts. On rifles with recoil pads and fixed butt-plates, make sure the screws are tight and that holes in the stock aren’t stripped out. Make sure there are no cracks in the stock and around the butt-plate. If the recoil pad is glued-on, just make sure it hasn’t come loose.

Next I take the action out of the stock and check for cracks and wear marks. I look at the bedding to make sure that oils and cleaning solvents have not damaged the bedding. While the action is out of the stock, I look for any surface rust or dirt/dust in the recoil lug area and magazine well. Clean as needed and repair or re-bed if needed.

Trigger Assembly and Action
Jewell trigger Remington 700With the barreled action out of the stock, it is a good time to spray out the trigger with cleaner. I use Ronson oil or lighter fluid. [Editor’s Note: Some trigger-makers advise against using any kind of lubricant, grease or oil — so plain lighter fluid is preferred.] After the trigger is cleaned you may want to check the trigger pull weight. If you don’t feel comfortable doing this, take it to a gun smith and have it checked. It is worth every penny to not have a trigger issue and/or a safety malfunction. I also take the bolt apart and clean the firing pin spring and bolt housing with Gun Scrubber or automotive brake cleaner. Then lube the firing pin-spring and firing pin with light oil. I use Kel Lube and/or Butch’s gun oil. Put a small dab of gun grease on the [bolt locking lugs] and cocking ramp.

I will also spray the outside of the action and barrel and give that a light coating of oil for rust prevention. I clean the action with Sinclair’s action cleaning tool. Don’t forget to clean the bore. Even though you didn’t fire the rifle, this makes sure nothing obstructs your barrel.

Checking Metal Fixtures and Fasteners
rifle scope ringsNext I look at the trigger guard and hinged floor plate and make sure it works as designed. Make sure there are no cracks in the trigger guard from an accidental drop. Check guard screws and /or action screws for tightness and tighten to proper spec. There are torque specs for this, but on wood stocks the wood can crush and this should be checked throughout the year as weather change can affect this. My entire collection of rifles are bedded and I just tighten them just snug with screw driver or Allen wrench. The rimfire rifles have a spec of 55 to 74 inch/lbs and I think would carry over to center fire as well. I would caution you about torque wrenches as you need a good quality wrench, and read the directions on how to use it. You can over torque if not careful. Check the swivel studs and bipod to make sure there tight as well. You may want to take scope off and check the base screws and check the rings.

Test Fire the Rifle After Maintenance
After all cleaning and is done and everything is reassembled, take a few rounds out to the range and test fire to make sure everything works as it should. Don’t forget to run 3-5 rounds through the magazine at least two times for function. I look at this as preventive maintenance on the rifle. If you give it a look over you shouldn’t have any trouble during the rifle matches or hunting trip.

Ron Dague
Certified Reloading Instructor
Certified Range Safety Officer
Email: rond [at] sinclairintl.com
Phone: 800-717-8211

Spring pre-season gun maintenance safety

This Article Originally Appeared in Sinclair International’s The Reloading Press.
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October 13th, 2021

7 SAFE: Seven Vital Safety Tips for Reloaders

seven reloading safety tips powder primers brownells manual

You can never be too safe when hand-loading your own ammunition. This helpful Brownells video outlines the Seven Fundamental Reloading Safety Tips. This is important information for novice hand-loaders and a good refresher for those with reloading experience!

Summary of the Seven Safety Tips:

1. Store your reloading supplies in a safe and dry location, away from children and away from any possible source of ignition. It is also smart to keep your powder and primers separate.

2. Get and use respected reloading manuals, especially for new cartridges. Start low and work up slowly while watching for warning signs of pressure and/or case fatigue.

3. Locate your reloading activity where you will not be distracted. If you get interrupted, stop. (Distractions will eventually lead to mistakes.)

4. Do NOT mix powders. Keep your powders clearly marked and dated. You can use masking tape to write the date on the container.

5. If you load the same cartridge type for different firearms, make sure your ammo headspaces properly in each gun.

6. Check cases frequently. Look for split necks, case head separation or other signs of fatigue and excessive pressure.

7. If reloading military brass, be aware that case capacity is usually reduced, and initial loads should be at least 10-15% lower than published data.


Here are some other tips that will help your avoid making costly mistakes (such as using the wrong powder, or undercharging a case):

  • Powder Type — Always double-check the label on your powder containers. After placing powder in the powder measure, put a piece of tape on the measure with the powder type written on it. Some guys write the powder type on a card and place that right in the hopper.
  • Scale Drift — Electronic balances can drift. If you are using a digital powder scale, calibrate the scale with a test weight every 50 rounds or so.
  • Case Fill — If you throw more than one charge at a time, look INSIDE every case before seating a bullet. Squib charges can be dangerous if you don’t notice them before firing the next round.
  • Progressive Presses — When using a progressive press, consider using an RCBS Lock-Out Die. This will detect a low charge and stop the machine. These dies will work with RCBS, Hornady, and Dillon progressives.

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May 16th, 2021

Don’t Kill Yourself — Bore Obstructions Cause Nasty Accidents

Obstructed Barrel Explosion Accident kaboom
Above is a sectioned barrel showing an 80gr Sierra that was fired in a .223 bolt action with a cleaning rod in the bore. Both the bullet and the rod are still in the bore.

A Negligent Shooter Gets Lucky
“Here we have a story so filled with negligent acts that I can only marvel that the shooter survived the experience. The photo and narrative were provided by the gunsmith who took in the repair job, my comments are in italics. It’s worth reading, we can’t get enough safety warnings in our hobby.” — GS Arizona, Rifleman’s Journal

Description of Incident (with Commentary)
The shooter had a stuck case in his .223 chamber. The stuck case was actually a loaded round that didn’t fire. It wouldn’t extract because it was a .222 case that got mixed in with his .223 brass. [He had loaded the wrong brass.] I saw the loaded round with an 80gr bullet in it and a light primer strike. Negligent Act #1: Wrong brass was mixed in with the brass being reloaded.

The shooter removed the stuck case with a 3-piece aluminum rod. Negligent Act #2: Hammering out a loaded round with a cleaning rod. People have been killed doing this as the round can fire and drive the cleaning rod right into you. I remember one such incident about 5 years ago, the shooter was pounding out a stuck round, the cleaning rod went right through him, he didn’t survive.

The shooter didn’t notice only two segments of the cleaning rod came out when he removed it. Negligent Act #3: If you put anything at all down the barrel of a rifle you’d better make darn sure you got it all out before doing anything else!

He then chambered another round and fired it. Negligent act #4: If you’ve had a barrel obstruction of any kind, and if you’ve put something in the barrel, look through the barrel before proceeding! Within the past two years I know of an incident in which a benchrest shooter was killed in exactly this manner. The pressure built up and the rifle bolt came out of the receiver and into his chest.

The shooter is ‘OK’, but did not escape unscathed. He said there was a huge explosion and after regaining his senses found he was bleeding heavily from his forehead. The blood was thick enough that it ran in his eyes and he couldn’t see. In his words “I thought I was going to die”.

He has what looks like a pretty deep cut about an inch long on the side of his head, right in line with his right eye starting where the eye socket turns out to the side of the skull. And no telling what he’s got in the way of brass particles embedded in his forehead.

He was shooting on private property, and was alone when this happened. Negligent Act #5: Don’t shoot alone! Accidents happen, this is just one more example. If we could predict accidents, we wouldn’t have them. Always shoot with at least one other person.

He managed to get the bleeding stopped, or at least under control, packed his car and drove himself home without seeking immediate medical attention. Negligent Act #6: This one could have cost him his life after being lucky enough to survive the incident. There’s no way to know what’s happened just after an incident like this. He should have been at a hospital getting checked for shrapnel in the head.

The rod and slug could not be driven out. Since the barrel had a high round count there was no point in trying to salvage it. Note that the aluminum rod is expanded to a tight fit in the bore for the first couple inches. The base of the bullet is a little over 2″ from the mouth of the chamber.

What we’ve seen here is negligence and an absolute indifference to the established rules of safe reloading and gun handling, from start to finish, capped off with the shooter’s foolish avoidance of medical treatment. This shooter is lucky to be alive, but he’s surely used up all his luck. Don’t assume you’ll be so fortunate.

This article originally appeared in the Rifleman’s Journal website, which is no longer available.

Permalink - Articles, Bullets, Brass, Ammo, Gunsmithing, Tech Tip 1 Comment »
March 30th, 2021

Know Your Terminology — CUP vs. PSI

SAAMI CUP PSI Cartridge Copper Units Pressure PSI
Image by ModernArms, Creative Common License.

by Philip Mahin, Sierra Bullets Ballistic Technician
This article first appeared in the Sierra Bullets Blog

If you asked a group of shooters to explain the difference between CUP and PSI, the majority would probably not be able to give a precise answer. But, for safety reasons, it’s very important that all hand-loaders understand these important terms and how they express cartridge pressures.

The ANSI / SAAMI group, short for “American National Standard Institute” and “Sporting Arms and Ammunition Manufacturers’ Institute”, have made available some time back the voluntary industry performance standards for pressure and velocity of centerfire rifle sporting ammunition for the use of commercial manufacturers. [These standards for] individual cartridges [include] the velocity on the basis of the nominal mean velocity from each, the maximum average pressure (MAP) for each, and cartridge and chamber drawings with dimensions included. The cartridge drawings can be seen by searching the internet and using the phrase ‘308 SAAMI’ will get you the .308 Winchester in PDF form. What I really wanted to discuss today was the differences between the two accepted methods of obtaining pressure listings. The Pounds per Square Inch (PSI) and the older Copper Units of Pressure (CUP) version can both be found in the PDF pamphlet.

SAAMI CUP PSI Cartridge Copper Units Pressure PSICUP Pressure Measurement
The CUP system uses a copper crush cylinder which is compressed by a piston fitted to a piston hole into the chamber of the test barrel. Pressure generated by the burning propellant causes the piston to move and compress the copper cylinder. This will give it a specific measurable size that can be compared to a set standard. At right is a photo of a case that was used in this method and you can see the ring left by the piston hole.

PSI Pressure Measurement
What the book lists as the preferred method is the PSI (pounds per square inch or, more accurately, pound-force per square inch) version using a piezoelectric transducer system with the transducer flush mounted in the chamber of the test barrel. Pressure developed by the burning propellant pushes on the transducer through the case wall causing it to deflect and make a measurable electric charge.

Q: Is there a standardized correlation or mathematical conversion ratio between CUP and PSI values?
Mahin: As far as I can tell (and anyone else can tell me) … there is no [standard conversion ratio or] correlation between them. An example of this is the .223 Remington cartridge that lists a MAP of 52,000 CUP / 55,000 PSI but a .308 Winchester lists a 52,000 CUP / 62,000 PSI and a 30-30 lists a 38,000 CUP / 42,000 PSI. It leaves me scratching my head also but it is what it is. The two different methods will show up in listed powder data[.]

So the question on most of your minds is what does my favorite pet load give for pressure? The truth is the only way to know for sure is to get the specialized equipment and test your own components but this is going to be way out of reach for the average shooter, myself included. The reality is that as long as you are using printed data and working up from a safe start load within it, you should be under the listed MAP and have no reason for concern. Being specific in your components and going to the load data representing the bullet from a specific cartridge will help get you safe accuracy. [With a .308 Winchester] if you are to use the 1% rule and work up [from a starting load] in 0.4 grain increments, you should be able to find an accuracy load that will suit your needs without seeing pressure signs doing it. This is a key to component longevity and is the same thing we advise [via our customer service lines] every day. Till next time, be safe and enjoy your shooting.

SAAMI CUP PSI Cartridge Copper Units Pressure PSI

Permalink Reloading, Tech Tip 4 Comments »
March 23rd, 2021

Incipient Case-Head Separation — How to Detect the Problem

cartridge case separation

We are re-publishing this article at the request of Forum members who found the information very valuable. If you haven’t read this Safety Tip before, take a moment to learn how you can inspect your fired brass to determine if there may be a potential for case separation. A case separation can be dangerous, potentially causing serious injury.

cartridge case separationOn the respected Riflemans’ Journal blog there was an excellent article about Cartridge Case-Head Separation. In this important article, Journal Editor GS Arizona examined the causes of this serious problem and explained the ways you can inspect your brass to minimize the risk of a case-head separation. As cases get fired multiple times and then resized during reloading, the cases can stretch. Typically, there is a point in the lower section of the case where the case-walls thin out. This is your “danger zone” and you need to watch for tell-tale signs of weakening.

The photo below shows a case sectioned so that you can see where the case wall becomes thinner near the web. You can see a little arrow into the soot inside the case pointing to the thinned area. This case hadn’t split yet, but it most likely would do so after one or two more firings.

cartridge case separation

Paper Clip Hack for Detecting Problems
The article provided a great, easy tip for detecting potential problems. You can use a bent paper clip to detect potential case wall problems. Slide the paper clip inside your case to check for thin spots. GS Arizona explains: “This simple little tool (bent paper clip) will let you check the inside of cases before you reload them. The thin spot will be immediately apparent as you run the clip up the inside of the case. If you’re seeing a shiny line on the outside and the clip is really hitting a thin spot inside, it’s time to retire the case. If you do this every time you reload, on at least 15% of your cases, you’ll develop a good feel for what the thin spot feels like and how it gets worse as the case is reloaded more times. And if you’re loading the night before a match and feel pressured for time — don’t skip this step!”

Permalink Bullets, Brass, Ammo, Reloading 3 Comments »
February 4th, 2021

Important Reloading Safety Tips from Sierra Bullets

Sierra Bullets Reloading Tips

Here are some really smart tips for hand-loaders compiled by Sierra Bullets. These suggestions were submitted by Sierra’s Facebook fans — and some are very valuable indeed. Some of these tips will help you load more accurate ammo. Other selections will help you stay SAFE — which should always be your #1 priority. For example, we concur with the advice to “Check and Double Check. Everything. Every Time”. Also definitely keep “One powder on the bench at a time” — that could be a life-saver. You may want to print these “words of wisdom” and place them on a wall in your loading room.

Reloading Safety Tips — Sound Advice

ALWAYS START LOW: “Just because a load manual says X grains of X powder with X bullet is max, your rifle could reach max pressure a grain or two before what the book says. Start low and work up.” — Walter Coats

BE SAFE: “Check and double check. Everything. Every time. Only one type of powder on the bench at a time.” — Glen Lundgren

DON’T RUSH: “Be patient, don’t be in a hurry, have fun and find your rhythm. Just tell your family you’re putting yourself in ‘time-out’. They will understand.” — Erik Dyal

POWDER RULE #1: “One powder on the bench at one time, it might save your life.” — James A. Kimery

STAY FOCUSED: “Relaxed but concentrated attention. Have fun enjoying a great hobby and pastime but stay focused.” — Jim Caldwell

POLICE LOADING AREA: “Keep your reloading bench area clean and put items away ASAP.” — Eric J. Ford

BE PATIENT: “Focus, Focus, Focus — be patient — it AIN’T a race.” — William Stanley

RECORD YOUR LOADS: “Write down on a small card what you’re loading – bullet weight, powder weight, type of powder, and primer. And put it in the powder hopper. I am unloading .45 FMJ because I forgot what type powder was in the hopper.” — Michael Conniff

HAVE a PROCEDURE for INTERRUPTIONS: “If, for any reason, you have to leave the bench while in the process of dropping powder charges, turn the next case to be charged upside down in the loading block so you know where you left off.” — Bill Tinsley

LABEL EVERYTHING: “OCD is a good habit to have with your loading bench. CLEARLY label everything!” — Andy Pynckel

HAVE a GOAL: “Never start reloading or developing a load without a specific goal in mind. Second keep meticulous records.” — Peter Eick

RESEARCH THE JOB: “Read all you can about it before you start!” — Keith Shively

KEEP TRACK: “I put all my primed brass upside down (primer up) and as I charge the casing, I (of course) flip it primer down.” — Mark Ewing

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January 20th, 2021

Doh! Make Sure Your Ammo Fits Your Chamber!

Ruptured Cartridge Case

If you don’t match your ammo to your chamber, bad things can happen, that’s for sure. A while back, Forum member BigBlack had an experience at the gun range that reminds us of the importance of safety when shooting. He encountered evidence that someone had fired the wrong cartridge in a 7mm WSM rifle. The problem is more common than you may think. This Editor has personally seen novices try to shoot 9mm ammo in 40sw pistols. BigBlack’s story is along those lines, though the results were much more dramatic. It’s too bad a knowledgeable shooter was not nearby to “intervene” before this fellow chambered the wrong ammo.

7mm-08 is Not the Same as a 7mm WSM
BigBlack writes: “I know this has probably been replayed a thousand times but I feel we can never be reminded enough about safety. This weekend at the range I found a ruptured case on the ground. My immediate thoughts were that it was a hot load, but the neck area was begging for me to take a closer look, so I did. I took home the exploded case and rummaged through my old cases until I found a close match. From my investigative work it appears someone shot a 7mm-08 in a 7mm WSM. Take a look. In the above photo I’ve put together a 7mm WSM case (top), the ruptured case (middle), and a 7mm-08 case (bottom).”

The photo reveals what probably happened to the 7mm-08 case. The shoulder moved forward to match the 7mm WSM profile. The sidewalls of the case expanded outward in the much larger 7mm WSM chamber until they lacked the strength to contain the charge, and then the case sides ruptured catastrophically. A blow-out of this kind can be very dangerous, as the expanding gasses may not be completely contained within the action.

Can’t Happen to You? Think Again.
This kind of mistake — chambering the wrong cartridge — can happen to any shooter who is distracted, who places even a single wrong round in an ammo box, or who has two types of ammo on the bench. One of our Forum members was testing two different rifles recently and he picked up the wrong cartridge from the bench. As a result, he fired a .30-06 round in a .300 Win Mag chamber, and the case blew out. Here is his story:

“I took two of my hunting rifles I have not used for over 25 years to the range yesterday to get new scopes on paper, a .30-06 and .300 Win Mag. I had four boxes of old Winchester factory ammo (two of each cartridge), which had near identical appearances. I accidentally chambered a .30-06 round in the Sako .300 Win Mag rifle. It sprayed powder on my face and cracked the stock at the pistol grip. If I had not been wearing safety glasses I might be blind right now.

Safety eyewear glasses
You should always wear protective eyewear, EVERY time you shoot.

“I feel lucky and am very thankful for being OK — other than my face looks funny right now. I am also grateful for learning a valuable lesson. I will never put two different cartridges on the bench at the same time again.”

READ More about this incident in our Shooters’ Forum.

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May 21st, 2020

Learn How the Human Ear Works — And Protect Your Hearing

hearing protection inner ear anatomy science hearing medical electronic muffs earplugs

hearing protectionAll shooters, even rimfire enthusiasts, should always wear ear protection when at the range. A typical rifle gunshot is very loud — in the region of 140 to 170 decibels (the pain threshold is 130-140 db). Without ear protection, you can permanently damage your hearing during a single shooting session. We all know older shooters who are partially deaf, or who suffer from Tinnitus, because they didn’t use earplugs or muffs when they were younger.

How Humans Hear Sounds — Amazing Video Reveals All
The human sense of hearing involves multiple delicate internal membranes, bones, organs, and nerves. Shooters understand the importance of protecting their hearing, but they may not understand the bio-mechanics of human hearing. We hear sounds through Auditory Transduction. Sound waves vibrate the ear drum (tympanic membrane), but that is only the beginning. These vibrations are passed along via tiny rocker-arm-like bones to be “processed” in a spiral chamber, the cochlea.

This remarkable VIDEO explains how humans hear sounds. We strongly recommend you take the time to watch and learn. The hearing you save may be your own!

Click Speaker Icon to turn on the video’s soundtrack.

Vibrations moving through the cochlea are separated into frequencies and then sent as neural messages to the brain. It is an astonishingly complex process, one that truly seems miraculous when you examine the bio-engineering involved. In the Video above, the process of human Auditory Transduction is explained and illustrated with 3D animation. You really should watch this amazing video. By the end you will have a new-found appreciation for your ability to hear.

hearing protection inner ear anatomy science hearing medical electronic muffs earplugs

Every shooter should own a pair of Electronic muffs, even if you prefer shooting with earplugs and/or standard muffs. Electronic muffs are great when you are spotting for other shooters or are working near the firing line. They let you hear ordinary conversations while still providing vital hearing protection. You can also wear ear-plugs under muffs for extra sound attenuation.

shooting ear protection nrr 33 ear plugs howard leightPlugs PLUS Ear-Muffs — The Benefits of “Doubling-Up” Your Hearing Protection
According to OHS Online: “The combined attenuation of an ear plug and an ear muff is not simply the algebraic sum of the performance of each individual protector. This is due to an acoustic and vibratory interaction between the ear muff and the ear plug that causes them to behave together as a system rather than as independent hearing protectors.

Generally speaking, when you combine two hearing protectors, ear muffs over ear plugs, you can expect an increase [in noise reduction] of between 3 and 10 dB over the higher-performing hearing protector. OSHA [now advises] 5 dB as the [typical] benefit offered by combining hearing protectors.” Source: OHSonline.com

Ear diagram courtesy Siemens Medical Solutions.

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February 26th, 2020

Spring Reminders — Pre-Season Rifle Maintenance Checks

Spring pre-season gun maintenance safety

March is just four days away. That means the spring shooting season will soon be starting. Before you head to the range for the first time, we recommend you do some basic tasks with your firearms. Here’s some good advice on readying your rifles for the 2020 shooting season.

by Ron Dague, Sinclair International
Firearms SafetyI give my rifles a pre-season check before the shooting season starts. This starts with a general inspection starting with the butt-plate or recoil pad and making sure that all the screws and adjustable parts (on an adjustable butt-plate) move freely up or down and side to side. If you got caught in rain some of these screws and adjustable parts may not move when needed. I disassemble parts as needed and put rust preventative or a light oil and/or grease on threads and sliding parts. On rifles with recoil pads and fixed butt-plates, make sure the screws are tight and that holes in the stock aren’t stripped out. Make sure there are no cracks in the stock and around the butt-plate. If the recoil pad is glued-on, just make sure it hasn’t come loose.

Next I take the action out of the stock and check for cracks and wear marks. I look at the bedding to make sure that oils and cleaning solvents have not damaged the bedding. While the action is out of the stock, I look for any surface rust or dirt/dust in the recoil lug area and magazine well. Clean as needed and repair or re-bed if needed.

Trigger Assembly and Action
Jewell trigger Remington 700With the barreled action out of the stock, it is a good time to spray out the trigger with cleaner. I use Ronson oil or lighter fluid. [Editor’s Note: Some trigger-makers advise against using any kind of lubricant, grease or oil — so plain lighter fluid is preferred.] After the trigger is cleaned you may want to check the trigger pull weight. If you don’t feel comfortable doing this, take it to a gun smith and have it checked. It is worth every penny to not have a trigger issue and/or a safety malfunction. I also take the bolt apart and clean the firing pin spring and bolt housing with Gun Scrubber or automotive brake cleaner. Then lube the firing pin-spring and firing pin with light oil. I use Kel Lube and/or Butch’s gun oil. Put a small dab of gun grease on the [bolt locking lugs] and cocking ramp.

I will also spray the outside of the action and barrel and give that a light coating of oil for rust prevention. I clean the action with Sinclair’s action cleaning tool. Don’t forget to clean the bore. Even though you didn’t fire the rifle, this makes sure nothing obstructs your barrel.

Checking Metal Fixtures and Fasteners
rifle scope ringsNext I look at the trigger guard and hinged floor plate and make sure it works as designed. Make sure there are no cracks in the trigger guard from an accidental drop. Check guard screws and /or action screws for tightness and tighten to proper spec. There are torque specs for this, but on wood stocks the wood can crush and this should be checked throughout the year as weather change can affect this. My entire collection of rifles are bedded and I just tighten them just snug with screw driver or Allen wrench. The rimfire rifles have a spec of 55 to 74 inch/lbs and I think would carry over to center fire as well. I would caution you about torque wrenches as you need a good quality wrench, and read the directions on how to use it. You can over torque if not careful. Check the swivel studs and bipod to make sure there tight as well. You may want to take scope off and check the base screws and check the rings.

Test Fire the Rifle After Maintenance
After all cleaning and is done and everything is reassembled, take a few rounds out to the range and test fire to make sure everything works as it should. Don’t forget to run 3-5 rounds through the magazine at least two times for function. I look at this as preventive maintenance on the rifle. If you give it a look over you shouldn’t have any trouble during the rifle matches or hunting trip.

Ron Dague
Certified Reloading Instructor
Certified Range Safety Officer
Email: rond [at] sinclairintl.com
Phone: 800-717-8211

This Article Originally Appeared in Sinclair International’s The Reloading Press.
Permalink Hunting/Varminting, Tech Tip No Comments »
November 23rd, 2019

Eyeball Your Brass — How to Diagnose Flawed Cases

Case Diagnostics 101 Sierra Bullets .223 Rem 5.56 brass cartridge safety

Ever wondered what caused a particular bulge or marking on a case? And more importantly, does the issue make the case unsafe for further use? Sierra Bullets Ballistic Technician Duane Siercks offers some insight into various issues and their causes in two Case Diagnostic articles from the Sierra Blog.

Incipient Case-Head Separation
This is a Winchester .308 Win case that has a real issue. This case has a very obvious incipient case head separation in the process of becoming a complete failure.

Sierra Case reloading pressure safety inspection

This is most commonly caused by over-sizing the case causing there to be excess headspace on the case. After a few firings and subsequent re-sizing, this case is just about ready to come completely apart. Proper die adjustment is certainly a requirement here. Of course this case is not safe to reuse.

Excessive Pressure (Load Too Hot)
If you will notice in the picture of the case rim, there are two pressure signs to notice. First, look at the primer. It is basically flattened to about the max of what could be considered safe. If this was the only pressure sign noted, I would probably be fine with this load, but would constantly keep an eye on it especially if I was going to use this load in warmer temperatures. This load could easily cross into the “excess pressure” realm very quickly.

Sierra Case reloading pressure safety inspection

There is another sign of pressure that we cannot ignore. If you’ll notice, there is an ejector mark apparent that is located over the “R” of the R-P headstamp. This absolutely tells us that this load would not have been in the safe pressure range. If there were any of these rounds loaded, they should not be fired and should be dis-assembled. This case should not be reloaded.

Split Case-Neck
Here we have an R-P .22-250 case that has died the death. Everything looks fine with this case except the neck is split. This case must be tossed.

Sierra Case reloading pressure safety inspection

A split neck is a normal occurrence that you must watch for. It is caused by work-hardening of the brass. Brass cases get harder with age and use. Brand new cases that are stored for a period of time can become hard enough that they will split like this case within one to two firings. I have had new factory loads do the same thing. Then as we resize and fire these cases repeatedly, they tend to get harder and harder. Eventually they will split. The life of the case can be extended by careful annealing practices. This is an issue that would need to be addressed in an article by itself. Of course this case is no longer usable.

In the classes that I teach, I try to use examples like this to let the students see what they should be looking for. As always, if we can assist you, whether you are new to reloading or very experienced, contact us here at Sierra Bullets by phone at 1-800-223-8799 or by email at sierra@sierrabullets.com.

Dented Case Body
Here we have a Lake City 7.62×51 (.308 Win.) case with two heavy marks/dents in the case body.

Sierra Case reloading pressure safety inspection

This one may be a bit of a mystery. It appears as if this case may have been caught in the action of a semi-auto rifle when the firearm jammed or the case failed to clear during the cycling process. I probably would not reload this case just to prevent any feeding problems. This also appeared to be a factory loaded round and I don’t really see any pressure issues or damage to the case.

Multiple Problems — Lake City 5.56×45 unknown year.

Sierra Case reloading pressure safety inspection

This case has suffered multiple failures and cannot be re-used. First its has have a very rounded shoulder that is split. Upon first look it was obvious that this round had been a victim of excess pressure. The firearm (perhaps an AR?) was apparently not in full battery, or there was possibly a headspace issue also. While taking a closer look, the primer was very flat and the outside radius of the primer cup had been lost. High pressure! Then I also noticed that there was an ejector mark on the case rim. This is most certainly an incident of excessive pressure. This case is ruined and should be discarded.

CLICK HERE for MORE .223 Rem Case Examples in Sierra Blog

To see more examples, view both Part I and Part II of the Case Diagnostics from Sierra Bullets:

» Reloading 101: Case Diagnostics Part I
» Reloading 101: Case Diagnostics Part II

It is very important to observe and inspect your cases before each reloading. After awhile it becomes second nature to notice the little things. Never get complacent as you become more familiar with the reloading process. If ever in doubt, call Sierra’s Techs at 1-800-223-8799.

Sierra Bullets Case Diagnostics Blog

Permalink Bullets, Brass, Ammo, Reloading, Tech Tip 1 Comment »