Figure 1. When the bullet is seated farther out of the case, there is more volume available for powder. This enables the cartridge to generate higher muzzle velocity with the same pressure.
Effects Of Cartridge Over All Length (COAL) And Cartridge Base To Ogive (CBTO) – Part 1 by Bryan Litz forBerger Bullets.
Many shooters are not aware of the dramatic effects that bullet seating depth can have on the pressure and velocity generated by a rifle cartridge. Cartridge Overall Length (COAL) is also a variable that can be used to fine-tune accuracy. It’s also an important consideration for rifles that need to feed rounds through a magazine. In this article, we’ll explore the various effects of COAL, and what choices a shooter can make to maximize the effectiveness of their hand loads.
Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI)
Most loading manuals (including the Berger Manual), present loading data according to SAAMI (Sporting Arms and Ammunition Manufacturers’ Institute) standards. SAAMI provides max pressure, COAL and many other specifications for commercial cartridges so that rifle makers, ammo makers, and hand loaders can standardize their products so they all work together. As we’ll see later in this article, these SAAMI standards are in many cases outdated and can dramatically restrict the performance potential of a cartridge.
Bullet seating depth is an important variable in the accuracy equation. In many cases, the SAAMI-specified COAL is shorter than what a hand loader wants to load their rounds to for accuracy purposes. In the case where a hand loader seats the bullets longer than SAAMI specified COAL, there are some internal ballistic effects that take place which are important to understand.
Effects of Seating Depth / COAL on Pressure and Velocity
The primary effect of loading a cartridge long is that it leaves more internal volume inside the cartridge. This extra internal volume has a well known effect; for a given powder charge, there will be less pressure and less velocity produced because of the extra empty space. Another way to look at this is you have to use more powder to achieve the same pressure and velocity when the bullet is seated out long. In fact, the extra powder you can add to a cartridge with the bullet seated long will allow you to achieve greater velocity at the same pressure than a cartridge with a bullet seated short.
When you think about it, it makes good sense. After all, when you seat the bullet out longer and leave more internal case volume for powder, you’re effectively making the cartridge into a bigger cartridge by increasing the size of the combustion chamber. Figure 1 illustrates the extra volume that’s available for powder when the bullet is seated out long.
Before concluding that it’s a good idea to start seating your bullets longer than SAAMI spec length, there are a few things to consider.
Geometry of a Chamber Throat
The chamber in a rifle will have a certain throat length which will dictate how long a bullet can be loaded. The throat is the forward portion of the chamber that has no rifling. The portion of the bullet’s bearing surface that projects out of the case occupies the throat (see Figure 2).
The length of the throat determines how much of the bullet can stick out of the case. When a cartridge is chambered and the bullet encounters the beginning of the rifling, known as the lands, it’s met with hard resistance. This COAL marks the maximum length that a bullet can be seated. When a bullet is seated out to contact the lands, its initial forward motion during ignition is immediately resisted by an engraving force.
Seating a bullet against the lands causes pressures to be elevated noticeably higher than if the bullet were seated just a few thousandths of an inch off the lands.
A very common practice in precision reloading is to establish the COAL for a bullet that’s seated to touch the lands. This is a reference length that the hand loader works from when searching for the optimal seating depth for precision. Many times, the best seating depth is with the bullet touching or very near the lands. However, in some rifles, the best seating depth might be 0.100″ or more off the lands. This is simply a variable the hand loader uses to tune the precision of a rifle.
Shown is the Redding Model 15-P Competition Piloted Inside Chamfering Tool with pilot rod that centers in the case flash hole. Also shown is a Forster 45° Rocket Tool.
There are a wide variety of reloading tools designed to cut a slight chamfer in case necks and deburr the edge of the case mouth. You don’t need to spend a lot of money for an effective tool. A basic “rocket-style” 45° chamfering tool, such as the Forster, actually does a pretty good job taking the sharp edge off case mouths, particularly if you use a little scotch-pad (or steel wool) to smooth the edge of the cut. The Forster chamfer tool, shown below, is a nicely-made product, with sharper cutting blades than you’ll find on most other 45° chamferers. It costs $26.99 at Brownells.com.
Redding sells a handy piloted chamfering tool with a 15° inside cutting angle and removable accessory handle. This Redding Model 15-P chamferer works really well, so long as you have consistent case OALs. The pilot rod (which indexes in the flash hole) is adjustable for different cartridge types (from very short to very long). This ensures the concentricity of the inside neck chamfer to the case mouth. This quality tool works with cases from .22 to .45 Caliber, and retails for $42.99 at MidwayUSA.
Sinclair International offers a 28° carbide chamferer with many handy features (and sharp blades). The $29.99 Sinclair Carbide VLD Case Mouth Chamfering Tool will chamfer cases from .14 through .45 caliber. This tool features a removable 28° carbide cutter mounted in the green plastic Sinclair handle.
Many folks feel they can get smoother bullet seating by using a tool that cuts at a steeper angle. We like the 22° cutter sold by Lyman. It has a comfortable handle, and costs just $19.99 at Cabelas.com. The Lyman tool is an excellent value, though we’ve seen examples that needed sharpening even when new. Blade-sharpening is easily done, however.
K&M makes a depth-adjustable, inside-neck chamferer (“Controlled Depth Tapered Reaper”) with ultra-sharp cutting flutes. The latest version, which costs $64.40 at KMShooting.com, features a central pin that indexes via the flash hole to keep the cutter centered. In addition, the tool has a newly-designed handle, improved depth-stop fingers, plus a new set-screw adjustment for precise cutter depth control. We caution, even with all the depth-control features, if you are not careful, it is easy to over-cut, slicing away too much brass and basically ruining your neck. We think that most reloaders will get better results using a more conventional chamfer tool, such as the Forster or Redding 15-P.
One last thing to note — tools like the K&M and the Sinclair chamferer are often described as VLD chamferers. That is really a misnomer, as bullets with long boat-tails actually seat easily with very minimal chamfering. In reality, these high-angle chamferers may be most valuable when preparing brass for flat-base bullets and bullets with pressure rings. Using a 22° or 28° chamferer can reduce the risk of cutting a jacket when using VLD bullets though — so long as you make a smooth cut.
The anvil is the tripod-shaped thin metal piece protruding above the bottom of the primer cup. Getting the primer sitting fully flush on the bottom of the case primer pocket, without crunching it too much, requires some keen feel for the progress of primer seating.
In two informative Midsouth Blog articles, the late Glen Zediker* offered helpful advice on priming. First he examined what happens to the primer itself as it is seated in the cup. Glen explained why some “crush” is important, and why you never want to leave a high primer. Glen also reviewed a variety of priming tools, including his favorite — the Forster Co-Ax Bench Primer Seater. Then he offered some key safety tips. Glen provides some “rock-solid” advice about the priming operation. There are many other smart reloading tips in Glen’s excellent Top-Grade Ammo book (now out of print).
Priming Precision vs. Speed
Glen writes: “The better priming tools have less leverage. That is so we can feel the progress of that relatively very small span of depth between start and finish. There is also a balance between precision and speed in tool choices, as there so often is.”
Benchtop Priming Tools — The Forster Co-Ax
Glen thinks that the best choice among priming options, considering both “feel” and productivity, may be the benchtop stand-alone priming stations: “They are faster than hand tools, and can be had with more or less leverage engineered into them. I like the one shown below the best because its feeding is reliable and its feel is more than good enough to do a ‘perfect’ primer seat. It’s the best balance I’ve found between speed and precision.”
Load Tuning and Primers
Glen cautions that you should always reduce your load when you switch to a new, not-yet-tested primer type: “The primer is, in my experience, the greatest variable that can change the performance of a load combination, which is mostly to say ‘pressure’. Never (never ever) switch primer brands without backing off the propellant charge and proving to yourself how far to take it back up, or to even back it off more. I back off one full grain of propellant [when I] try a different primer brand.”
Priming Safety Tips by Zediker
1. Get a good primer “flip” tray for use in filling the feeding magazine tubes associated with some systems. Make double-damn sure each primer is fed right side up (or down, depending on your perspective). A common cause of unintentional detonation is attempting to overfill a stuffed feeding tube magazine, so count and watch your progress.
2. Don’t attempt to seat a high primer more deeply on a finished round. The pressure needed to overcome the inertia to re-initiate movement may be enough to detonate it.
3. Don’t punch out a live primer! That can result in an impressive fright. To kill a primer, squirt or spray a little light oil into its open end. That renders the compound inert.
4. Keep the priming tool cup clean. That’s the little piece that the primer sits down into. Any little shard of brass can become a firing pin! It’s happened!
* Glen Zediker — Sadly, in 2020 Glen Zediker passed away. We covered his career and his accomplishments as a marksman, reloading guru, and gun industry writer in this memorial article: Glen Zediker, 1959-2020, In Memoriam
A fire in the home is always to be feared. And a fire in your reloading room can be disastrous. Near your reloading bench you probably have flammable solvents, and maybe gunpowder. What would happen if an electrical fire started in your reloading room? Would you be alerted? Do you have a proper fire extinguisher at hand?
Here’s a true story from Forum Member Joe O. (aka “Joecob”) that provides a valuable safety lesson. After Joe started up his old tumbler, an internal connector worked loose, causing an arc which started a fire in his basement reloading area. Luckily Joe had a functioning smoke detector, and a fire extinguisher.
Very few of us would worry about fire when we plug in a tumbler or other AC-powered reloading tool. But there is always the possibility of a malfunction and a fire. Quick thinking (and a handy extinguisher) prevented serious damage to Joe’s reloading room and house — but things could have been worse (much worse), had Joe not responded quickly.
Fire in the Reloading Room — Report by Joecob
The day before ‘Sandy’ hit I was cleaning brass the way I always have. I set the vibratory tumbler on the back of my reloading bench in the basement. I loaded the media hopper with 40 fired empty brass cases (and walnut media), plugged the cord in, turned the tumbler on and went back upstairs to watch TV. I could hear the tumbler running in the background.
About half an hour later I heard the basement smoke alarm go off. I ran downstairs. Flames were licking from the melting plastic of the tumbler.
I grabbed the nearby ABC cannister extinguisher and squirted out the fire and soaked the charred bench areas with water. Good thing I had the extinguisher! And I was glad I religiously store powder and primers properly — away from the bench (and everything else).
What caused the fire? It looks like an internal AC connector finally vibrated loose enough to arc and ignite the plastic. WHEH! I had been using that thing for 25 years the same way without mishap. Guess I should have known to periodically check the guts of a thing that plugs in and vibrates for a living?
Today I went out and bought a new even bigger ‘Pro’ ABC extinguisher, plus a dual-detector smoke alarm, and an ultrasonic cleaner. That experience was scarier than the storm. I hope this true account might help someone else to avoid a bad experience.
In his account, Joe refers to an “ABC” cannister fire extinguisher. The “ABC” refers to the fire classification rating: Class A (trash, wood, and paper), Class B (liquids and gases), and Class C (energized electrical equipment) fires. There are many brands of ABC-rated extinguishers.
The sturdy, rechargeable Kidde Pro 210 Fire Extinguisher (SKU 21005779) contains four pounds of a multipurpose monoammonium phosphate dry chemical extinguishing agent. It has a discharge time of 13 to 15 seconds, a discharge range of 10 to 15 feet, and an operating pressure of 100 PSI. The seamless aluminum cylinder measures 4.5 inches in diameter and 15.7 inches tall. The Kidde 210 has a 6-year warranty. This is $41.79 on Amazon (#ad), 40% off the $69.99 MSRP price.
Chart created with Ammoguide’s Visual Comparison Tool. Visit Ammoguide.com to learn more.
One of our forum members was looking for a very accurate, mid-sized 6.5mm cartridge for target working and coyote hunting. There are many great options including the 6.5 Grendel, 6.5×47 Lapua, 6.5 Creedmoor, and Remington .260 (a 6.5-08). If you are considering the 6.5×47 you should read our 6.5×47 Cartridge Guide authored by the 6.5 Guys. This and other 6.5mm cartridges are covered in this introduction to 6.5 mm cartridges prepared by Eben Brown, President of Eabco.com.
Quick Guide to 6.5mm Cartridges
by Eben Brown, EABCO.com, (E. Arthur Brown Co. Inc.)
The current popularity of 6.5mm cartridges in the USA has been a long time in coming. I won’t go into my opinions on why it took so long to catch on. The important thing is that it finally HAS caught on and we’re now so fortunate to have a wide selection of 6.5mm cartridges to choose from!
6.5mm Grendel – Developed by Alexander Arms for the AR15 and military M4 family of rifles. The Grendel fits the dimensional and functional requirements of these rifles while delivering better lethality and downrange performance. [Editor: The little 6.5 Grendel delivers a lot of performance from a small package. This is one of the most accurate cartridge options for the AR15 platform.]
6.5mm BRM – Developed by E. Arthur Brown Company to give “Big Game Performance to Small Framed Rifles” — namely our Model 97D Rifle, TC Contender, and TC Encore. Velocities of 2400-2500 fps with 140gr bullets puts it just under the original 6.5×55 Swede performance.
6.5mm x 47 Lapua – Developed by Lapua specifically for international 300m shooting competitions (with some interest in long-range benchrest as well). Case capacity, body taper, shoulder angle, and small rifle primer are all features requested by top international shooters. You can expect velocities of 2500-2600+ with 140 gr bullets.
6.5mm Creedmoor – Developed by Hornady and Creedmoor Sports, the 6.5mm Creedmoor is designed for efficiency and function. Its shape reaches high velocities while maintaining standard .308 Winchester pressures and its overall length fits well with .308 Win length magazines. You can expect velocities of 2600-2700+ fps with 140gr bullets. [Editor: Yep, we know some PRS guys are loading hotter than that in bolt guns. We recommend you try the 120-130 grain bullets also with this cartridge. That may put you in a better accuracy node.]
This video reviews 6.5 Creedmoor Cartridge Brass options:
.260 Remington – Developed by Remington to compete with the 6.5mmx55 Swedish Mauser that was (finally) gaining popularity in 1996. By necking down the 7mm-08 Remington to 6.5mm (.264 cal), the .260 Remington was created. It fit the same short-action [receivers] that fit .308 Win, .243 Win, 7mm-08 Rem, etc. You can expect velocities of 2600-2700 fps with 140gr bullets in the 260 .Remington.
[Editor’s Note: In the .260 Rem, try the Lapua 120gr Scenar-Ls and/or Berger 130gr VLDs for great accuracy and impressive speeds over 2950 fps.]
6.5mm x 55 Swedish Mauser – This was the cartridge that started the 6.5mm craze in the USA. It is famous for having mild recoil, deadly lethality on even the biggest game animals, and superb accuracy potential. Original ballistics were in the 2500 fps range with 140gr bullets. Nowadays handloaders get 2600-2700+ fps.
[Editor’s Note: Tor from Scandinavia offers this bit of 6.5x55mm history: “Contrary to common belief, the 6.5×55 was not developed by Mauser, but was constructed by a joint Norwegian and Swedish military commission in 1891 and introduced as the standard military cartridge in both countries in 1894. Sweden chose to use the cartridge in a Mauser-based rifle, while Norway used the cartridge in the Krag rifles. This led to two different cartridges the 6.5×55 Krag and 6.5×55 Mauser — the only real difference being safe operating pressure.”]
6.5-284 Norma — This comes from necking the .284 Winchester down to .264 caliber. Norma standardized it for commercial ammo sales. The 6.5mm-284 was very popular for F-Class competition and High Power at 1,000 yards. However, many F-Class competitors have switched to the straight .284 Win for improved barrel life. 6.5-284 velocities run 3000-3100+ fps with 140gr bullets.
.264 Winchester Magnum – Developed by Winchester back in 1959, the .264 Win Mag never really caught on and may have delayed the ultimate acceptance of 6.5mm cartridges by US shooters (in my opinion). It missed the whole point and original advantage of 6.5 mm cartridges.
The Original 6.5mm Advantage
The special needs of long-range competition have skewed things a little. However the original advantages of 6.5mm cartridges — how deadly the 6.5mms are on game animals, how little recoil they produce, and how easy they are to shoot well — still hold true today.
We’re told the 6.5 Creedmoor is now the best-selling chambering in new bolt-action rifles sold in the USA. Accurate, versatile, with moderate recoil, the 6.5 Creedmoor cartridge serves hunters, paper punchers, and PRS/NRL shooters equally well.
As part of its online Load Data Center, Nosler offers very complete load data for the popular 6.5 Creedmoor cartridge. This medium-sized cartridge combines excellent accuracy, good mag-feeding, good barrel life, moderate recoil, and reasonable component cost. That’s why this cartridge has become very popular for multiple shooting disciplines. GET ALL 6.5 Creedmoor Load Data.
How does barrel length affect 6.5 Creedmoor Muzzle Velocity? CLICK HERE for RifleShooter.com barrel cut-down velocity test.
According to the Sierra Load Manual: “Developed in 2007 by Dennis DeMille and Dave Emary, the 6.5 Creedmoor is a shortened and improved 30 TC cartridge case that was inspired by the .308 Winchester design. This short action design was created to maximize case capacity and a wide range of loading lengths, while still fitting in standard short action magazines. With the correct twist barrel, the versatile 6.5 Creedmoor can take advantage of the wide range of bullet weights available in 6.5 mm (i.e. .264 caliber). Reloaders should keep in mind that the 6.5 Creedmoor works best with medium to medium-slow powders such as H4350, Varget, Win 760, and RE-17.”
Click Each Image to Load PDF File for Listed Bullet Weights
Here’s something you’ve probably never seen before — a single-shot, bolt-action pistol chambered for the 6mmBR Norma cartridge (aka 6BR). Featured as one of our Guns of the Week a while back, this Green Machine is a Savage Striker upgraded by Chuck G. from Arizona, a self-described “Savage Maniac”. This impressive bolt-action pistol has shown exceptional accuracy.
Chuck transformed this Savage Striker single-shot from a ho-hum .308 into a reliable half-MOA precision 6BR that can run with accurized rifles all the way out to impressively long ranges. Here we provide highlights from our original article. Click the link below to read our full Savage Striker article, which is three times longer than this story, and has more photos, plus videos and a detailed load development section.
The Striker Project — Pursuit of Precision, by Chuck G.
I didn’t even know Savage Strikers existed until I saw one for sale on Gunbroker.com. I snagged it with a $400 bid. My idea was to build an accurate, long-range pistol on a pauper’s budget. As purchased, the Striker had a .308 barrel with an unknown round count, the standard center-grip, black synthetic stock, an odd two-piece custom brake, and an old Burris 4X pistol scope in a Conetrol 2-piece ring set. The trigger was very heavy, 6-8 lbs I’d estimate, with a lot of take-up and over-travel.
Initial Disappointments — Too Much Recoil, Poor Accuracy
My initial attempts to get the Striker to shoot well at even 100 yards were disappointing. I was never able to get better than a 3″, 5-shot group at 100. Not what I was looking for. Being used to benchrest triggers, the pull on this one was hard for me to manage. The gun would roll around on any type of front rest I had, and from a cement bench on a bipod it would jump about 18 inches up and sideways with every round. Not being used to this type of gun, I found the recoil and muzzle blast to be unsettling. It was hard not to flinch. I started off using my 1K .308 rifle load, 175 SMKs over 44 grains of Varget. That probably would have knocked the hell out of a deer, but it wasn’t much fun to shoot from the bench.
New Caliber, New Barrel — Way Better Accuracy!
I decided to rebuild the Striker in a caliber that would be more fun to shoot. 6mmBR was an obvious choice for all the usual reasons–good brass, wide choice of match bullets, easy to load, low recoil, very accurate, and relatively cheap to shoot. As part of a SavageShooters.com group buy, I ordered a 15″, SS match grade, 3-groove, heavy varmint contour, 10-twist barrel from Pac-Nor. To set the freebore, I provided Pac-Nor with a dummy case with an 88gr LD Berger bullet seated to use as a guide. Total delivered price was $340 chambered and threaded for a muzzle brake from JP Rifles.
This image below features a target created by the founder of AccurateShooter.com and 6mmBR.com. You can CLICK HERE to visit our target page with this and many other free targets.
When I bought it, the Striker, with factory .308 barrel, shot 3″ groups at 100. Now, with a Pac-Nor 6BR Match barrel, 3″ fore-arm plate, upgraded trigger, 24X scope, and match bullets, the gun consistently groups 1/2″ or better at 100 yards. What a transformation!”
Striker Project — Mission Accomplished
With further load development and bench practice, the gun is showing even more accuracy potential. Using a 24X target scope, the Striker has delivered 5-shot groups in the 3s and 4s during recent range visits. All in all, I’m very satisfied with the project. I ended up with an accurate, fun-to-shoot gun for under $1,000 including scope, paint, and bedding materials.
Stock Modifications
While waiting for the barrel I started working on the stock. As virtually no aftermarket stocks were readily available for the center-grip Striker, I decided to rebuild the standard black synthetic stock. The grip fit my hand poorly so I worked it over with a Dremel tool and sandpaper, built up the grip with Bondo, filled in some holes and bedded the action using Devcon Plastic Steel. This was my very first attempt at these tasks so progress was slow. Once I had re-shaped the stock, I sprayed five coats of “John Deere” green topped by several coats of auto clear. It came out surprisingly well considering I had never painted a stock before. I had originally planned to build up the fore-end to 3″ wide using Bondo but later decided to just use a Sinclair Benchrest Adapter that I had on hand.
Chuck notes: “I’m really pleased with the C & J one-piece Rest. It’s solid, heavy, and well-designed. There is no real need for a windage top; small adjustments are easily made by slightly shifting the pistol butt. Elevation adjustments are positive and once the pistol is set up on this rest NOTHING moves.”
Lyman’s popular E-Zee Case Length Gauge II is now bigger and better. The latest version of Lyman’s Case Gauge is much larger than the original version. The Case Gauge II now measures more than 70 cartridge types — way more than before. This tool is a metal template with SAAMI-max-length slots for various cartridge types, including modern cartridges such as the Winchester Short Magnums. This tool allows you to quickly sort brass or check the dimensions. If you have a bucketful of mixed pistol brass this can save you hours of tedious work with calipers. You can also quickly check case lengths to see if it’s time to trim your fired brass.
If you load a wide variety of calibers, or do a lot of pistol shooting, we think you should pick up one of these Lyman Case Gauge templates. They are currently available for $24.99 at Brownells, $25.99 at MidwayUSA, and $30.53 on Amazon. The E-Zee Case Gauge has long been a popular item for hand-loaders.
NOTE: For years the E-Zee Case Gauge had a silver finish with black lettering, as shown above. Some of the most recent production of E-Zee gauges have a new “high contrast” look, with white lettering on a black frame. You may get either version when you order online — Brownells and MidwayUSA show silver, while Amazon shows black. We actually prefer the older silver version. Below is the black and white variant.
Lyman Case Gauge Should Last a Lifetime
Easily measure the case length of over 70 popular rifle and pistol cases with Lyman’s E-Zee Case Length Gauge. This really is a “must-have” piece of kit for any gun owner who hand-loads numerous pistol and rifle calibers.
This precisely-made metal gauge makes sorting or identifying cases fast and accurate. The template is machined with SAAMI max recommended case lengths. Made from metal, with no moving parts, the E-Zee Case Gauge should last a lifetime. The Lyman E-Zee Gauges offered by Brownells are silver with black lettering, while other Case Gauge models are black with white lettering.
Bryan Litz and The Science of Accuracy Academy have released a Podcast with vital information for all handloaders. This Podcast examines the effects of humidity variances on powder. Bryan notes: “If you want to know how much this can matter, we’re talking up to 200 fps difference for the same load of H4350 in 6.5 Creedmoor” at opposite extremes of humidity.
Bryan adds that “Most shooters don’t realize what a big deal this can be — it overshadows many of our efforts to make consistent velocity and hit targets. This can happen in loaded rounds not just for hand loading where you expose powder to ambient humidity. This is especially important for hunters considering the range of environments hunting ammo goes through.”
Subscriptions for Applied Ballistics The Science of Accuracy Academy Podcasts
If you like this podcast, and want to learn more from Brian Litz and his Applied Ballistics team, you can order a subscription to the Academy. Priced at $9.95/mo, this subscription will allow you to access all podcasts, exclusive videos, learning resources, and bullet data sheets.
by Sierra Bullets Ballistic Technician Gary Prisendorf
Occasionally someone will ask, “Why did I get a flyer that didn’t go in with the rest of my group?” If I had an answer that would stop flyers from happening, I would be rich.
There are many reasons why this can happen. Everything from gripping a forearm differently to variations in the brass casing, the list goes on and on. Most of the time the flyer is usually shooter induced and sometimes what you may think is a flyer, is just part of your group. There are a lot of shooters, that go out and test a load and they may shoot a 3/8” group at 100 yards and think that load is good. But I have seen far too many times that you can shoot another group, same load, same rifle and the next time you may get a 1 ¼” group.
The total opposite can also occur. You may shoot a 1 ¼” group and turn around and follow it with a 1/2″ group without changing anything. If you only shot the one group, you might decide that load wasn’t any good and move on to something else without really knowing what that load was capable of.
To really determine how a particular load is performing we need to shoot multiple groups and take an average of the group sizes to really see what that rifle/load combination is really capable of.
I suggest shooting a minimum of three 5-shot groups and averaging the group sizes before deciding if the load is acceptable or not. Obviously the more rounds you shoot for a group and the more groups that you shoot, you will get a much better representation of what that particular combination can do.
Now I’m not saying to go out and shoot 30 groups with 50 rounds in each group to determine how well your load is shooting. That would be a bit pointless, in some cases it would be time to re-barrel your rifle before your load development was finished.
In most cases, I feel that three to five, 5-shot groups will give you a pretty good representation of how a load will perform in that specific firearm.
Effects Of Cartridge Over All Length (COAL) And Cartridge Base To Ogive (CBTO) – Part 1
In two informative Midsouth Blog articles, the late Glen Zediker* offered helpful advice on priming. First he examined what happens to the primer itself as it is seated in the cup. Glen explained why some “crush” is important, and why you never want to leave a high primer. Glen also reviewed a variety of priming tools, including his favorite — the 
A fire in the home is always to be feared. And a fire in your reloading room can be disastrous. Near your reloading bench you probably have flammable solvents, and maybe gunpowder. What would happen if an electrical fire started in your reloading room? Would you be alerted? Do you have a proper fire extinguisher at hand?
I grabbed the nearby ABC cannister extinguisher and squirted out the fire and soaked the charred bench areas with water. Good thing I had the extinguisher! And I was glad I religiously store powder and primers properly — away from the bench (and everything else).
In his account, Joe refers to an “ABC” cannister fire extinguisher. The “ABC” refers to the fire classification rating: Class A (trash, wood, and paper), Class B (liquids and gases), and Class C (energized electrical equipment) fires. There are many brands of ABC-rated extinguishers.
.260 Remington – Developed by Remington to compete with the 6.5mmx55 Swedish Mauser that was (finally) gaining popularity in 1996. By necking down the 7mm-08 Remington to 6.5mm (.264 cal), the .260 Remington was created. It fit the same short-action [receivers] that fit .308 Win, .243 Win, 7mm-08 Rem, etc. You can expect velocities of 2600-2700 fps with 140gr bullets in the 260 .Remington.
Here’s something you’ve probably never seen before — a single-shot, bolt-action pistol chambered for the 6mmBR Norma cartridge (aka 6BR). Featured as one of our 
Lyman’s popular 
