Can sustained rapid-fire shooting with no cool-down period wear out a quality barrel more quickly? The answer is “Yes” according to Forum member LCazador, who did an interesting comparison test with two .243 Winchester barrels. He started off with two, identical, match-grade HV taper stainless barrels. Both were NEW at the start of testing, and LCazador shot the same load through each: 95gr match bullets with 38 grains of Hodgdon Varget. After giving both barrels the same, gentle 20-round break-in, 300 rounds were then fired through each barrel — in very different ways. Barrel condition and wear were monitored with a borescope.
Barrel One — Slow Fire, Cool Down Periods, Cleaning Every 50 Rounds
At the end of the 300-round test, Barrel One looked brand new. There was none of the severe fire cracking found in Barrel Two. This barrel was shot no more than 10 times without a cool down and firing was done at a much slower pace. Cleaning for this barrel was done every 50 shots.
Barrel Two — Fast Firing, No Waiting, Cleaning Every 100 Rounds
The second barrel, which received hard use and minimal cleaning, was severely damaged with severe fire cracking at the leade and throat. As a result, the barrel had to be re-chambered. This barrel was shot 100 rounds at time without cleaning and was shot up to 20 times in succession without a cool down.
LESSON LEARNED — Heat Kills Barrel Life
Don’t let your barrel get too hot, and keep it clean. One afternoon can ruin a barrel!
Monitoring Barrel Wear with Borescope
Some folks worry too much about what their borescopes reveal — many barrels do not have to be “squeaky clean” to perform well. In fact some barrels run better after ten or more fouling shots. However, a borescope can be very helpful when your barrel starts losing accuracy for no apparent reason. Forum member FdShuster writes:
“A borescope is a positive way of backing up your suspicions when the rifle starts to throw an occasional (soon followed by more frequent) wild shot. Using the scope is also an excellent way to determine that the cause is barrel wear and not simply a need for a concentrated cleaning session to remove built up copper and more importantly, carbon fouling.
I’ve had a few barrels that gave every indication of being shot out. But I ‘scoped them out and found the cause to be nothing more than requiring a good cleaning. They then returned to their usual performance. There’s no guessing involved when you are able to get ‘up close and personal’ using the scope. The borescope also provides an excellent view of the all-important condition of the crown. My borescope is one of the most valuable investments I’ve ever made.”
AR-platform rifles can be maintenance-intensive beasts. They need regular inspection, cleaning, and lubrication. But some AR owners make the situation worse by not regularly cleaning important small parts, or by using too MUCH oily/greasy lubricants in the wrong places. A properly maintained and lubricated AR15 can shoot hundreds of rounds (between cleanings) without a problem. If you learn where (and where not) to apply lubricant, you’ll find that your AR will run more reliably and the task of cleaning the bolt, bolt carrier, and upper receiver internals will be less of a burden.
Here we showcase videos that show how to field-strip an AR-15, inspect the key parts, clean components, and lubricate internal parts as needed. Along with these videos, we recommend you read the comprehensive AR-15 Gun Cleaning Clinic article from the Brownells website. This explains in detail important procedures that the videos might only cover in a few seconds.
If you want to keep your black rifle running smoothly and reliably, you must clean it regularly and follow the correct maintenance procedures. Here are five videos that explain how to properly disassemble and clean AR-platform rifles.
1. How To Clean Your AR-15 | Cleaning and Maintenance Tips
This is a quick 90-second starter video that may help new AR owners. Ricky Lehnhardt of OTIS Technology demonstrates the basics of cleaning and maintaining your AR-15. Lehnhardt does a good job identifying the points that need cleaning on the inside of ARs. However he works very quickly in the video. You may want to pause the video at some points. Also, Lehnhardt employs a cable for pulling patches and brushes through the barrel. Yes this is fast and easy. However, for match AR rifles, we recommend that you instead use a cleaning ROD with fitted bore guide.
2. Take-Down and Full Cleaning of AR-15 by Jerry Miculek
Here ace shooter Jerry Miculek takes down and cleans an AR-platform rifle belonging to his daughter Lena. This is a good video because Lena’s rifle was “run hard and packed up dirty” so you can see where carbon and grease build up. This 35-minute video is very thorough. Jerry is one of the nation’s top action carbine shooters, so listen carefully to his advice on cleaning and lubrication.
3. AR-15 Maintenance: Field-strip, Clean and Lubricate an AR-15
Gunsite Academy instructor and gunsmith Cory Trapp demonstrates the proper way to field-strip, clean, and lubricate an AR-15 carbine. In this 30-minute video, Trapp offers several important technical tips and hints. For example, at 11:05 Trap demonstrates how to determine if your bolt needs new gas rings. Along with cleaning procedures, this video explains how to inspect key components and how to function-test your AR before each shooting session.
4. AR-15 Dissassembly and Cleaning Guide
This video does a good job, with close-ups, showing how to remove the bolt carrier and clean the inside of the upper receiver. Then you can see how to work with various tools to clean the bolt, bolt carrier, and inside of chamber. We also recommend that you inspect the ejector recess and extractor recess. When we’ve inspected ARs that failed to cycle properly, we have often found nasty gunk (mixture of carbon, greasy lube, and brass particles) in these areas.
5. Basic AR-15 Quick and Easy Field Maintenance
In this NSSF-sponsored video, pro shooter Ryan Muller demonstrates basic, quick field maintenance of his AR-15. This would be for a quick cleaning and lubrication of the reciprocating parts. This covers rapid maintenance in the field. For full field-stripping and thorough cleaning, watch the previous videos.
Handy Mat for Cleaning AR Rifles
When working on an AR-15, it’s smart to have a pad that can absorb solvents and cushion your upper and lower. The $29.99 Real Avid Smart Mat is a good choice. This features printed take-down instructions and it has a handy parts tray on the right side. The mat rolls up for convenient storage. Click HERE to learn more.
Vital Inspections You Should Do After Disassembly
Last but not least, here are recommended inspections you should do every time you do a full field-strip and cleaning of your black rifle:
Burris Signature Rings with polymer inserts are an excellent product. The inserts allow you to clamp your scope securely without ring marks. Moreover, using the matched offset inserts you can “pre-load” your scope to add additional elevation. This helps keep the scope centered in its elevation range while shooting at long range. Additionally, with a -20 insert set in the front and a +20 insert set in the rear, you may be able to zero at very long ranges without using an angled scope base — and that can save money. (To move your point of impact upwards, you lower the front of the scope relative to the bore axis, while raising the rear of the scope.)
Insert Elevation Values and Ring Spacing
People are sometimes confused when they employ the Burris inserts. The inset numbers (-10, +10, -20, +20 etc.) refer to hundredths of inch shim values, rather than to MOA. And you need the correct, matched top/bottom pair of inserts to give you the marked thousandth value. Importantly, the actual amount of elevation you get with Burris inserts will depend BOTH on the insert value AND the spacing between ring centers.
Forum member Gunamonth has explained this in our Shooters’ Forum:
Working with Burris Signature Rings
Burris inserts are [marked] in thousandths of an inch, not MOA. To know how many MOA you gain you also need to know the ring spacing. For example, with a -20 thou insert set in the front and a +20 thou insert set in the rear, if the ring spacing is 6″, the elevation change will be approximately +24 MOA upwards.
Here’s how we calculate that. If you have a 2 X 0.020″ “lift” over a distance of 6 inches (i.e. 0.040″ total offset at 0.5 feet) that’s equivalent to 0.080″ “lift” over 12 inches (one foot). There are 300 feet in 100 yards so we multiply 0.080″ X 300 and get 24″ for the total elevation increase at 100 yard. (Note: One inch at 100 yards isn’t exactly a MOA but it’s fairly close.)
Here’s a formula, with all units in inches:
Total Ring Offset
——————– X 3600 = Change @ 100 yards
Ring Spacing
(.020 + .020)
—————– X 3600 = 24 inches at 100 yards
Ring Spacing: 6 inches
NOTE: Using the above formula, the only time the marked insert offset will equal the actual MOA shift is when the center to center ring spacing is 3.60″. Of course, you are not required to use 3.60″ spacing, but if you have a different spacing your elevation “lift” will be more or less than the values on the inserts.
Close-up of the Tri-Way Trimmer with clear plastic chip guard removed.
Giraud Tool offers a case trimmer/chamferer device that works with a power drill (or other power source). Giraud’s patented Tri-Way Trimmer is a self-contained unit powered by your drill or motor. Using a sharp carbide blade it will trim your cases to length, deburr, and cut both inside and outside chamfers — all in one pass. That’s pretty impressive for a $120.00 tool that fits in the palm of your hand.
Product Features
1. Fully adjustable for cartridge length (and depth of chamfer).
2. Carbide blade cuts a 15° inside case mouth chamfer and 45° outside chamfer.
3. Case holder supported by sealed ball bearing raceway.
4. Tool includes removable, transparent plastic chip guard.
5. Tool can work in any orientation (vertical, horizontal, or any angle).
The Giraud Tri-Way Trimmer is designed to be powered by a portable hand drill, drill press, or other dedicated rotating power source. The tool indexes off the shoulder of your cases, but the blade adjusts so that cartridge overall length (COAL) can be controlled with precision. Constructed out of 6061-T6 aluminum and 303 stainless steel, the Tri-Way tool should last a lifetime. Note: This tool is not universal. The Tri-Way is dedicated to a single cartridge and “related” cartridges with similar body dimensions. Thus you need a specific tool for each cartridge family. For example, the .308 Win tool will also trim .243 Win, .260 Rem, and 7mm-08.
The type of targets you use can make a difference during load development and training — helping you align your crosshairs, estimate group size visually, and also record load data/gun type. Here we provide selection of FREE printable precision and training targets. This selection includes popular load development targets AccurateShooter created as well as other useful grid targets. You can download ALL these targets as PDF files and then print them out on 8.5×11″ heavy paper.
AccurateShooter.com offers a cool page with over 50 FREE downloadable targets. You’ll find all types or FREE targets — sight-in targets, varmint targets, rimfire targets, bullseye targets, tactical targets, load development targets and more. CLICK HERE for all our free targets, including our LOAD DEV target.
We created the above target a decade ago. Since then it has been used by tens of thousands of shooters. It has proven very popular as a load development target, since all your load data fits neatly in the boxes under each target. In fact this target is being employed by both rifle-makers and barrel-makers (including Criterion) to test their products. The target was designed for aiming efficiency. The diamonds have 1/2″ sides and you can align your cross-hairs on the horizontal and vertical lines. It is a clean design that is easy to see even at 200 yards with a 20X scope. When we test, we usually crank in a little elevation, setting the point-of-impact higher, so that our shots fall in the gray circles. That way you leave the squares intact for precise aiming.
Versatile Targets with Multiple Aiming Points
We use the two targets below for load development and precision practice. For the left target, use the corners of the diamonds to align your cross-hairs precisely. The circle dot target (on the right) can also be used for informal rimfire competition at 50 yards. Right-Click Each Target to Download Printable PDFs.
Know-Your-Limits Target for Rimfire Training & Fun Matches
Here’s a rimfire training target with “big to small” target circles. Start with the largest circles, then move to the smaller ones in sequence. This systematic drill provides increasing challenge shot-by-shot. Novices often are quite surprised to see their accuracy improve as they move from bigger to smaller aiming points. That provides positive feedback — always a good thing.
Right Click and “Save as” to download printable PDF versions of target.
Five Diamond Grid Targets
Here’s a popular grid target with multiple red diamond aiming points. The background includes a grid pattern with 1″ squares — that helps to quickly estimate group size through your scope. We recommend using a color printer for this target so the diamonds and grid lines are bright red.
Here’s a NRA-type target for pistol shooting. The bright red center helps when shooting indoors because well-placed bullet holes are much more visible. This target includes data entry boxes to record gun type, score, and load data. This is one of many good free targets available at Targets4free.com.
Precision rifle shooters don’t have to hit a big-league fastball, or launch a top-fuel dragster in the blink of an eye. Nonetheless, reaction times are important in our sport — both for competitive shooters and hunters. Want to catch that prairie dog before he slips down his hole? You’ll need to be quick. Want to win at short-range benchrest? Then you’ll need to watch your windflags and respond quickly to a change. Miss a major wind-shift and you could ruin your whole weekend.
Here’s a fun test of reaction times from HumanBenchmark.com. The way it works is that, after clicking “Start”, you wait until the background color changes from red to green. The instant you see green, immediately click your mouse. The average (median) reaction time is 273 milliseconds, according to data collected so far. Hint: If you keep your finger “preloaded” in contact with your mouse button you can shave some milliseconds — but don’t “jump the gun”.
Tips for Faster Times
Here are three tips to speed up your reaction times:
1) Respond to the color change (by itself), rather than wait to read the word “CLICK!” after the box shifts to green.
2) Try focusing at the corner of the box, rather than the center. This may help you react “without thinking”.
3) Have your index finger “poised and ready” over the left button–you can shave milliseconds by very slightly depressing the button before you actually click.
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.
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.”
Readers who have just recently discovered the Daily Bulletin may not realize that AccurateShooter.com has hundreds of reference articles in our archives. These authoritative articles are divided into multiple categories, so you can easily view stories by topic (such as competition, tactical, rimfire, optics, shooting skills etc.). One of the most popular categories is our Technical Articles Collection. On a handy index page (with thumbnails for every story), you’ll find over 120 articles covering technical and gunsmithing topics. These articles can help you with major projects (such as stock painting), and they can also help you build more accurate ammo. Here are five popular selections from our Technical Articles archive.
Stress-Free Pillar Bedding. Richard Franklin explains how to do a top-quality bedding job, start to finish.
OnTarget Software Review. Our Editors test free software that measures shot groups with great precision. We explain how to use the program and configure advanced features.
Savage Action Tuning. Top F-TR shooter Stan Pate explains how to enhance the performance of your Savage rifle by optimizing the torque settings of the action screws.
Complete Precision Case Prep. Jake Gottfredson covers the complete case prep process, including brass weight sorting, case trimming, primer pocket uniforming, neck-sizing, and, case-neck turning.
Stock Painting Instructions. Step-by-step guide for stock painting by expert Mike Ricklefs. Mike shows both simple coverage and fancy effects.
It’s October, the fall season, and that means rainy, wet weather is on the way in many areas of the country. With rain comes increased moisture in the air, i.e. increased humidity. And that, in turn, can affect how your powders perform by altering their burn rates.
Most shooters realize that significant changes in temperature will alter how powders perform. That’s why you want to keep your loaded ammo out of the hot sun, and keep rounds out of a hot chamber until you’re ready to fire. But there are other factors to be considered — HUMIDITY for one. This article explains why and how humidity can affect powder burn rates and performance.
We’ve all heard the old adage: “Keep your powder dry”. Well, tests by Norma have demonstrated that even normal environmental differences in humidity can affect the way powders burn, at least over the long term. In the Norma Reloading Manual, Sven-Eric Johansson, head of ballistics at Nexplo/Bofors, presents a very important discussion of water vapor absorption by powder. Johansson demonstrates that the same powder will burn at different rates depending on water content.
Powders Leave the Factory with 0.5 to 1.0% Water Content
Johansson explains that, as manufactured, most powders contain 0.5 to 1% of water by weight. (The relative humidity is “equilibrated” at 40-50% during the manufacturing process to maintain this 0.5-1% moisture content). Importantly, Johansson notes that powder exposed to moist air for a long time will absorb water, causing it to burn at a slower rate. On the other hand, long-term storage in a very dry environment reduces powder moisture content, so the powder burns at a faster rate. In addition, Johansson found that single-base powders are MORE sensitive to relative humidity than are double-base powders (which contain nitroglycerine).
Tests Show Burn Rates Vary with Water Content
In his review of the Norma Manual, Fred Barker notes: “Johansson gives twelve (eye-opening) plots of the velocities and pressures obtained on firing several popular cartridges with dehydrated, normal and hydrated Norma powders (from #200 to MRP). He also gives results on loaded .30-06 and .38 Special cartridges stored for 663 to 683 days in relative humidities of 20% and 86%. So Johansson’s advice is to keep powders tightly capped in their factory containers, and to minimize their exposure to dry or humid air.”
Confirming Johansson’s findings that storage conditions can alter burn rates, Barker observes: “I have about 10 pounds of WWII 4831 powder that has been stored in dry (about 20% RH) Colorado air for more than 60 years. It now burns about like IMR 3031.”
What does this teach us? First, all powders start out with a small, but chemically important, amount of water content. Second, a powder’s water content can change over time, depending on where and how the powder is stored. Third, the water content of your powder DOES make a difference in how it burns, particularly for single-base powders. For example, over a period of time, a powder used (and then recapped) in the hot, dry Southwest will probably behave differently than the same powder used in the humid Southeast.
Reloaders are advised to keep these things in mind. If you want to maintain your powders’ “as manufactured” burn rate, it is wise to head Johannson’s recommendation to keep your powders tightly capped when you’re not actually dispensing charges and avoid exposing your powder to very dry or very humid conditions.
Real-World Example — “Dry” H4831sc Runs Hotter
Robert Whitley agrees that the burn rate of the powder varies with the humidity it absorbs. Robert writes: “I had an 8-lb. jug of H4831SC I kept in my detached garage (it can be humid there). 43.5-44.0 gr of this was superbly accurate with the 115 Bergers out of my 6mm Super X. I got tired of bringing it in and out of the garage to my house for reloading so I brought and kept the jug in my reloading room (a dehumidified room in my house) and after a few weeks I loaded up 43.5 gr, went to a match and it shot awful. I could not figure out what was going on until I put that load back over the chronograph and figured out it was going a good bit faster than before and the load was out of the “sweet spot” (42.5 – 43.0 gr was the max I could load and keep it accurate when it was stored in less humid air). I put the jug back in the garage for a few weeks and I now am back to loading 43.5 – 44.0 gr and it shoots great again. I have seen this with other powders too.”
If you have two jugs of the same powder, one kept in a room in your house and one somewhere else where it is drier or more humid, don’t expect the two jugs of the same lot of powder to chrono the same with the same charge weights unless and until they are both stored long enough in the same place to equalize again.
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.
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.
Monitoring Barrel Wear with Borescope
Tests Show Burn Rates Vary with Water Content
