Barnes Bullets has started a new Barnes Bullet Points podcast running on YouTube. Hosted by Barnes Bullets’ Marketing Mgr. Dale Evans, this podcast offers a behind-the-scenes look into the design and production of Barnes Bullets products along with use of Barnes Bullets in hunting and shooting sports.
The Barnes Bullet Points podcast will cover a variety of topics, blending technical and educational segments with real-world adventures and conversations with hunters and competitors. You can subscribe to the Barnes Bullets YouTube channel, follow on Spotify or Apple Podcasts. New podcasts will be released weekly. The first two podcasts are live now.
Episode 1: The History of Barnes
Barnes Podcast Number 1, The History of Barnes, was released last week. On the podcast, Evans is joined by Andrew Sparks and Gregg Sloan. The three men discuss Barnes Bullets’ origins, where it is today and what lies ahead. Together, they introduce both Barnes Bullets as a company and explain the Podcast goals.
Episode 2: Deep Dive into the Bullets
Podcast Episode 2 features Barnes bullet families. Listeners will learn more about the design features and performance of popular Barnes bullets. In this 75-minute podcast, Dale Evans is joined by Gregg Sloan and Mitchell Kukson. The three men discuss the features of Barnes TSX, TTSX, and LRX bullets. The podcast discusses how to select the optimal bullet type (for various scenarios), and the experts explain the performance you can expect to see from each. Watch this full 55-minute Podcast below:
“The Barnes Bullet Points podcast is a great resource for our loyal fans and end users to learn more about the brand, the products we offer and the people that help develop them”, said Evans.
Today, June 20, 2024 is Summer Solstice, the longest day of the year. And right now the Northeast USA is undergoing a major heatwave. That means “peak heat” summer conditions have arrived already. It’s vitally important to keep your ammo at “normal” temps during the hot summer months. Even if you use “temp-insensitive” powders, studies suggest that pressures can still rise dramatically when the entire cartridge gets hot, possibly because of primer heating.
It’s smart to keep your loaded ammo in an insulated storage unit, possibly with a Blue Ice Cool Pak if you expect it to get quite hot. Don’t leave your ammo in the car or truck — temps can exceed 140° in a vehicle parked in the sun.
The way ambient temperatures, barrel heating, and powder warming can affect cartridge pressures (and hence velocities) was covered in a study Pressure Factors: How Temperature, Powder, and Primer Affect Pressure by Denton Bramwell. In that article, the author used a pressure trace instrument to analyze how temperature affects ammo performance. Bramwell’s tests yielded some fascinating results.
For example, barrel temperature was a key factor: “Both barrel temperature and powder temperature are important variables, and they are not the same variable. If you fail to take barrel temperature into account while doing pressure testing, your test results will be very significantly affected. The effect of barrel temperature is around 204 PSI per F° for the Varget load. If you’re not controlling barrel temperature, you about as well might not bother controlling powder temperature, either. In the cases investigated, barrel temperature is a much stronger variable than powder temperature.”
This Editor had the personal experience of 6mmBR hand-loaded ammo that was allowed to sit in the hot sun for 45 minutes while steel targets were reset. The brass became quite warm to the touch, meaning the casings were well over 120° on the outside. When I then shot this ammo, the bullets impacted well high at 600 yards (compared to earlier in the day). Using a Magnetospeed, I then chron-tested the sun-heated ammo. The hot ammo’s velocity FPS had increased very significantly — all because I had left the ammo out in the hot sun uncovered for 3/4 of an hour.
LESSON: Keep your ammo cool! Keep loaded ammo in the shade, preferably under cover or in an insulated container. You can use a SEALED cool pack inside the container, but we do NOT recommend H20 ice packs. And don’t have the container do double duty for food and beverages.
Powder Heat Sensitivity Comparison Test
Our friend Cal Zant of the Precision Rifle Blog has published a fascinating comparison test of four powders: Hodgdon H4350, Hodgdon Varget, IMR 4451, and IMR 4166. The first two are Hodgdon Extreme powders, while the latter two are part of IMR’s Enduron line of propellants.
The testers measured the velocity of the powders over a wide temperature range, from 25° F to 140° F. Hodgdon H4350 proved to be the most temp stable of the four powders tested. [NOTE: New Alliant Reloder TS 15.5 has also proved very temp stable in AccurateShooter’s range tests.]
Over the past 12 months, this article was one of the TOP 20 most-read Daily Bulletin features. We’re reprising it today for those who may have missed it the first time. The above diagram comes from a TiborasurasRex YouTube Video comparing G1 and G7 BC models. CLICK HERE to watch the video.
The better, up-to-date ballistics programs let you select either G1 or G7 Ballistic Coefficient (BC) values when calculating a trajectory. The ballistic coefficient (BC) of a body is a measure of its ability to overcome air resistance in flight. You’ve probably seen that G7 values are numerically lower than G1 values for the same bullet (typically). But that doesn’t mean you should select a G1 value simply because it is higher.
Some readers are not quite sure about the difference between G1 and G7 models. One forum member wrote us: “I went on the JBM Ballistics website to use the web-based Trajectory Calculator and when I got to the part that gives you a choice to choose between G1 and G7 BC, I was stumped. What determines how, or which one to use?”
The simple answer is the G1 value normally works better for shorter flat-based bullets, while the G7 value should work better for longer, boat-tailed bullets.
G1 vs. G7 Ballistic Coefficients — Which Is Right for You?
G1 and G7 refer both refer to aerodynamic drag models based on particular “standard projectile” shapes. The G1 shape looks like a flat-based bullet. The G7 shape is quite different, and better approximates the geometry of a modern long-range bullet. So, when choosing your drag model, G1 is preferable for flat-based bullets, while G7 is ordinarily a “better fit” for longer, boat-tailed bullets.
Drag Models — G7 is better than G1 for Long-Range Bullets
Many ballistics programs still offer only the default G1 drag model. Bryan Litz, author of Applied Ballistics for Long Range Shooting, believes the G7 standard is preferrable for long-range, low-drag bullets: “Part of the reason there is so much ‘slop’ in advertised BCs is because they’re referenced to the G1 standard which is very speed sensitive. The G7 standard is more appropriate for long range bullets. Here’s the results of my testing on two low-drag, long-range boat-tail bullets, so you can see how the G1 and G7 Ballistic coefficients compare:
G1 BCs, averaged between 1500 fps and 3000 fps:
Berger 180 VLD: 0.659 lb/in²
JLK 180: 0.645 lb/in²
The reason the BC for the JLK is less is mostly because the meplat was significantly larger on the particular lot that I tested (0.075″ vs 0.059″; see attached drawings).
For bullets like these, it’s much better to use the G7 standard. The following BCs are referenced to the G7 standard, and are constant for all speeds.
Many modern ballistics programs, including the free online JBM Ballistics Program, are able to use BCs referenced to G7 standards. When available, these BCs are more appropriate for long range bullets, according to Bryan.
[Editor’s NOTE: BCs are normally reported simply as an 0.XXX number. The lb/in² tag applies to all BCs, but is commonly left off for simplicity.]
This article is copyright 2023 AccurateShooter.com. No 3rd Party republication of this article is allowed without advance approval and payment of licensing fees.
The Pew Pew Tactical website has interesting article on rifle and pistol cartridges and bullet types. This contains a large selection of interesting photographs and illustrations. If you load and/or shoot for a wide variety of cartridge types, you’ll find that article well worth reading. It has nearly 50 photographs and more than a dozen short videos. READ FULL Article.
The article also shows all types of pistol bullets, along with a variety of rifle projectiles. It even illustrates multiple types of shotshell cartridges.
The article also explains the basic components of modern cartridges — bullet, case, powder, and primer:
Photo courtesy Ammunitiontogo.com which sells ammo from many leading brands.
Popular Cartridge Types Profiled
The article provides quick summaries of popular ammunition types including 9mm Luger (9x19mm), .357 Magnum, .40 SW, .45 ACP, .223 Rem, and .308 Winchester. The author’s favorite pistol round is the 9mm Luger: “9mm is my personal favorite and if there was a “Goldilocks” round, this would be it. The very first gun I bought was a 9mm. They’re fun at the range. They’re good for defense. It is the standard round for NATO countries and the majority of police forces around the world. It is mild shooting, can vary in weight from 115 to 147 grains, and has varying stopping power based on the type of bullet.”
This Pew-Pew Tactical guide to cartridge types also provides a quick explanation of cartridge ignition — both centerfire and rimfire: “The rimfire’s primer is built into the rim while the centerfire cartridge has the primer in the center. Pro tip — if you can see a circle in the middle…it’s a centerfire cartridge.”
There are two common types of centerfire primers — Boxer and Berdan. This helpful Wikipedia illustration shows how Boxer, Berdan, and rimfire primers ignite the powder in the cartridge:
This centerfire and rimfire ignition animation is by BBODO – Own work, CC BY-SA 3.0 licensed under the Creative Commons Attribution-Share Alike 3.0 license.
Hodgdon Powder Company (Hodgdon) offers a series of informative, “how-to” instructional videos through its online Reloading Data Center. These 3.5-minute videos present rifle, pistol, and shotshell reloading basics in an easy-to-understand, step-by-step format. These mobile-friendly, informative videos can also be viewed on a smart phone or tablet.
To watch the reloading videos go to the Reloading Data Center at hodgdon.com. Click to the right/left of the displayed video to switch between pistol, rifle, and shotgun videos. Or, for your convenience, we have embedded the Rifle and Pistol videos here. Just click to watch!
Click to Watch Hodgdon Rifle Reloading Video:
Click to Watch Hodgdon Pistol Reloading Video:
In addition to these videos, Hodgdon’s Reloading Data Center (RDC) provides a wealth of information on Hodgdon, IMR, Accurate, Winchester, and Ramshot propellants. Along with reliable load data, you’ll find explanations of reloading basics, safety procedures, plus answers to frequently asked questions (FAQ).
Ace tactical shooter and gunsmith Jim See of Elite Accuracy LLC has tested a Frankford Arsenal rotary brass tumbler. Like the older Thumbler’s Tumblers, this can tumble your cases in a liquid solution. The wet-tumbling process worked very well Jim reports. Posting on Facebook, Jim noted: “I was super impressed with the Frankford Arsenal rotary tumbler and cleaning packs they sent me. I ran 350 pieces of brass for one hour. They now look great.” Jim appreciated not having to deal with dry tumbling media, such as crushed walnut shells. Dry media produces dust and can leave residues or clog flash-holes.
Interestingly, Jim recommends you try wet-tumbling WITHOUT using stainless media. At least give it a try. Tumbling without media simplifies the process and you don’t have to worry about pins stuck in flash-holes or case-necks*. Jim reports: “Stainless steel pins come with the Frankford kit, but mine hit the trash right out of the box. There is no need to clean the inside of your cases 100% and that’s all the pins add to the equation. The brass bumping brass with hot water and Frankford’s liquid cleaner works great all by itself.” One wag stated: “That’s great to hear. Stainless steel pins are a PITA.”
Other Facebook posters concurred with Jim’s evaluation of the Frankford Arsenal Rotary Tumbler:
“I’ve had one for a couple years, and it works well. I usually run about 250-300 Dasher cases at once in it. But I use the pins because I’m OCD about clean brass.” — David W.
“I’ve had one for a year and a half and it definitely works with or without pins.” — Luke C.
“I got one about six months ago and have yet to use any stainless steel media [pins]. I just use some dawn, distilled water, and Lemi Shine®. Turns nasty 5.56 range brass bright and shiny.” — Brian D.
“I don’t use the pins either and use a combination of Dawn soap and Lemi Shine.” — Jon N.G.
This video shows how to assemble and operate the Frankford rotary tumbler. But note, Jim See does NOT feel that it is necessary to use stainless media.
How to Dry Your Brass — Hair Dryer Vs. Machine
The downside of wet tumbling is that you end up with a pile of wet brass at the end of the cleaning cycle. There are many ways to dry brass, from drying in the sun to using a kitchen oven (be careful not to “overcook” your brass). One Facebook poster asked Jim: “What is your drying method for wet brass, and how long does it take?”
Jim See replied: “To start I just drain off the dirty water, and rinse the brass with clean hot water. Then I roll the brass on a towel for 30 seconds and put the brass in a one-gallon bucket. Next I insert a hair dryer in the bucket (with the brass) and let it run for about 5 minutes. With this procedure, the drying process for me is done in less than 10 minutes.”
Jack Lanhart has another method: “I use a food dehydrator. It takes 30 to 45 minutes.”
For those who don’t want to mess with towels and hair dryers, Frankford Arsenal offers a matching Platinum Series Case Dryer that simplifies the process of drying brass. Lyman also makes an excellent Cyclone Case Dryer. These drying machines each cost about $65.00 and both have multiple levels so you can separate different types of cartridge brass. Lyman states that “The forced heated air circulation of the Cyclone will dry your brass inside and out within an hour or two, with no unsightly water spots.” The Lyman dryer can also be used for ultrasonically-cleaned gun parts.
*The Frankford Rotary tumbler does include media separators if you choose to use the provided pins or other media. CLICK HERE for diagram showing how to use media separators.
OK guys, you probably want to keep this page confidential. Your spouse probably doesn’t want to be reminded about all the times you ignored the “Honey Do” list and headed off to the range instead. And she certainly doesn’t want to know how much you spend every year on your gun hobby.
Answer these two polls to see how dedicated (or should we say “obsessed”) a gun guy you really are. Once you vote you can see how your shooting (and spending) habits compare to other readers. Full results display after you select an answer and click the “Vote” button.
Click to vote in our current Readers’ polls.
Click “View Results” to see what other readers have selected.
The rifle cartridge money clip was a real product from ReleaseMeCreations.com (now sold out). You can, of course, make your own cartridge money clip with a Dremel tool for free.
This custom war wagon hauls varmint hunters around the Longmeadow Game Resort in Colorado.
Will you be heading to the varmint fields this summer? Proper planning is key to a safe, satisfying, and productive varmint holiday. Of course you’ll be busy reloading, but you should make a check-list of all the gear and supplies you need. Bring a variety of rifles if possible — you’ll need to switch off as one barrel gets hot, and the chambering that works best for your close shots may not be ideal for those longer shots out past 400 yards. Here are some tips from our Forum members that can help you shoot more effectively, and avoid problems on your varmint hunt. Here’s one key tip: at your shooting station, put a strip of surveyor’s tape on a tall stake to show the wind direction. Then shoot in the direction the wind blows. This will minimize the effect of cross-winds.
Varmint Safari Planning, Equipment, and Shooting Advice
From PatchHound: “The gear you bring will make or break a trip out to Prairie Dog land. A lot has to do with where you going and how far you are from [civilization]. For starters, bring lots of water. It will be hot in Wyoming in a few more weeks but it don’t hurt to bring warm clothes in case it snows. It’s best to wear leather boots unless you’re real good at dodging cactus while walking around. Good sunscreen [and a wide-brimmed hat] will save the day too. [What you need to bring] really depends on whether you’re shooting on some friendly ranch or 100 miles in the middle of [a wilderness area]. Good survival gear is a good thing to have for the latter!”
This photo is from a Dan Eigen TV Show video featuring a P-Dog hunt.
From Stoner25mkiv: “I’d suggest an adjustable bipod if you are going to do any walking. A laser rangefinder is a huge asset. Have a fanny pack or backpack for extra ammo, water, bore-snake, etc. when you go on your walkabouts. We also take a couple pivoting benches, heavy movers’ pad/blanket, sandbags (Uncle Bud’s Bulls Bag) for shooting from near the vehicle. Boonie hat for blocking the sun, sun glasses, sunscreen. High leather boots.
Anyway, on to the rifles…consider bringing a 17 HMR, .223 Ackley bolt gun, .223 Ackley AR, and a 243 WSSM. Some years the 17 HMR isn’t removed from its case. We had a couple windless days and the 17 was lots of fun. I’d walk into the dogtown and then lay down and wait. After five minutes or so I’d have dogs within easy rimfire range, and out to as far as I’d care to stretch the rimfire. 275 yards was about it.”
From CTShooter: “The .204 [Ruger] is a laser beam and good to 400 yards easy. Forget the rimfire! Do you have a portable bench that pivots? Bring bipod, binocs. Bring a LOT of water. I have a milspec sniper shooter’s mat/drag bag with shoulder straps. It is good to carry everything when you want to wander off and shoot prone with bipod. Here’s a view through my 6BR in ND.”
From RJinTexas: “In most of the locations that we’ll be shooting we’ll usually set up a minimum of 200 yards from the edge of a major dog town. We’ll start by working over the close-in dogs and shooting our way out, some of these towns may run in excess of 500/600 yards deep. I believe that a rimfire will put you at a distinct disadvantage. The only rimfire that will somewhat work is the 17 HMR and you can reload for your 204s for close to the cost of HMR ammo and you’ll be less apt to be under-gunned. Your 204 will work well out to 300/400 yards unless the wind is blowing hard. We classify a 10-mph crosswind as a very calm day and what makes it a little more challenging is that it is usually also gusting.”
From Wes (P1ZombieKiller): “[For my first PD trip] there are so many things I was not ready for. The one thing that I did bring (that no one told me about) was a canopy. I’m glad I did. Even though the weather was [near perfect], I know that sun can humble you real fast. With my pop-up canopy, I could shoot all day without getting killed by the sun. You had to tie the canopy down real well or the wind would blow it across the pasture.
We sat on shooting benches that pivot 360°, and are fast and easy to set up. Most all shots were 175-250 yards. I just felt comfortable at that range. It was more fun for me to be able to film the hits, and the camcorder I was using just did not get good video past 350 yards. The digital zoom distorted the image too much. I knew I would only get this one chance to film my first P-dog outing, and I wanted to get it on film for [posterity].”
Bring Multiple Rifles on Your Varmint Adventures
On our P-Dog adventures, we like to have multiple rifles — a .17 HMR for close work, then maybe a .20 Practical AR for 150-250 yards, then a larger caliber such as 6BRA, 6 Dasher or 6XC for those long shots. The classic 22-250 is also a wickedly effective varmint cartridge.
.20 Practical (20-223 Rem) AR-Platform Varminter
Here is a .20 Practical built by Robert Whitley. Whitley’s Ultimate Prairie Dog Rifle (PDR) features a 24″ Bartlein 11-twist cut-rifled barrel, DPMS side-charging upper, and a Jewell trigger. It is chambered in 20 Practical, a cartridge popularized by Warren “Fireball” Brookman.
This .20 Practical cartridge is simply the .223 Remington necked down to .204. You can use your existing .223 Rem brass — no special case-forming required! The 20 Practical is accurate, flat-shooting, and has almost no recoil. The advantage over the standard .223 Remington is that, grain for grain, the bullets have a higher BC and travel at a higher velocity for more dramatic effect on a small varmint. The ultra-low recoil allows you to easily see your hits, even without a muzzle brake. The 20 Practical, launching 40-grainers at about 3750 fps, shoots flatter than a .223 Rem with 55gr hollowpoints.
.17 HMR Savage A17 Varmint Rifle
We also like to have a Rimfire for the closer shots, inside 150 yards. The .17 HMR or .17 WSM are good choices. With a rimfire you save on ammo costs and you don’t waste precious centerfire barrel life.
This video shows a successful Prairie Dog hunt with a .17 HMR. Watch and you’ll see hits out to 160 yards (00:50), proving the effective range of the .17 HMR cartridge. The host is shooting a Savage A17 semi-auto .17 HMR rifle in a Boyds laminated stock.
Probably the most popular centerfire rifle round in the Western Hemisphere is the .223 Remington and its metric match, the 5.56x45mm. Though many folks use “.223 Rem” and “5.56×45″ interchangeably, there are some meaningful differences in specifications for the original .223 Rem and the 5.56x45mm cartridge, as adopted by the U.S. military and NATO armies. The default chamber throats are slightly different and the .223 Rem is rated at 55,000 PSI vs. 62,366 PSI for the 5.56x45mm.*
.223 Rem vs 5.56x45mm — Key Differences
There is a truly outstanding, very thorough article on the subject, published by LuckyGunner.com.** This involved extensive testing, with pressure monitors, of 5.56x45mm ammo in .223 Rem chambers. Those tests revealed the peak pressures. Here is one of the ammo test charts:
NOTE: “The observed chamber pressure for Federal XM855 5.56mm ammunition in a .223 Rem chamber exceeded .223 maximum pressures, but not by a massive amount. The ninth shot (the red line) was an underpowered cartridge which exhibited significantly lower velocity and pressure than the other rounds, so it was excluded from the average velocity and pressure numbers for this chamber.”
And if you’re curious, LuckyGunner also fired .223 Rem ammo in a 5.56x45mm NATO-chambered AR15 rifle. As you would expect, the peak pressures were significantly lower, but the .223 Rem ammo still cycled the semi-auto AR-platform rifle perfectly well:
UltimateReloader.com Explains .223 Rem vs. 5.56x45mm
To explain the key differences between the .223 Rem and 5.56x45mm cartridges our friend Gavin Gear of UltimateReloader.com has created a very thorough 12-minute video. This covers the cartridge specifications and explains key considerations for hand-loaders. Gavin also addresses the oft-asked question “Can I shoot 5.56x45mm ammo in my .223 Rem chamber?” Gavin’s video is definitely worth watching. In fact, this is one of the most popular videos Gavin has ever created — it has been watched nearly 4.5 million times on YouTube.
What Exactly Is the 5.56x45mm NATO Cartridge?
The 5.56×45mm NATO is a rimless bottle-necked intermediate cartridge family standardized by NATO with development work by FN Herstal. It consists of the SS109, SS110, and SS111 cartridges. Under STANAG 4172, it is a standard cartridge for NATO forces as well as many non-NATO countries.
Bullet diameter: 5.70 mm (0.224 in)
Maximum pressure (EPVAT): 430.00 MPa (62,366 psi)
Maximum pressure (SCATP 5.56): 380.00 MPa (55,114 psi)
Case length: 44.70 mm (1.760 in)
Rifling twist: 178 mm or 229 mm (1 in 7 in)
Parent case: .223 Remington (M193)
Ammo-Maker Federal Premium Compares .223 Rem and 5.56x45mm
Here is a video from ammo-maker Federal Premium explaining the difference between .223 Remington and 5.56x45mm NATO. Federal states that you may experience excessive pressures when firing a 5.56x45mm in a standard .223 Remington chamber:
One leading gunwriter has addressed the question of shooting 5.56x45mm ammo in .223 Rem chambers. He advocates caution (for more info, SEE pressure tests by LuckyGunner.com):
“I have received a slew of questions — many from first time AR-type rifle buyers — about the .223 Rem and the 5.56×45 mm NATO cartridges. Can I shoot 5.56×45 mm NATO in my .223 and vice-versa? Are these the same cartridge?
Externally, the two cartridge cases are identical. The main differences are that 5.56×45 mm NATO operates at a higher chamber pressure (about 60,000 PSI versus 55,000 PSI on the .223 Rem.) and the 5.56’s chamber is slightly larger than that of the .223 Rem. Also, the throat or leade is longer in the 5.56×45 mm chamber. What does this mean? You should not shoot 5.56×45 mm NATO out of a rifle that is chambered in .223 Rem [with a standard short throat]. And be aware that some .223 Rem ammunition will not reliably cycle through some AR-style .223 Rem rifles, but it usually does. As a matter of fact, I have not encountered any difficulty with current .223 Rem. loads cycling through a 5.56 mm AR-style rifle.” — Mark Keefe, Editor, American Rifleman
* According to the official NATO proofing guidelines, the 5.56×45mm NATO case can handle up to 430.0 MPa (62,366 psi) piezo service pressure. The U.S. SAAMI lists Maximum Average Pressure (MAP) for the .223 Remington cartridge as 55,000 psi (379.2 MPa) piezo pressure with deviation of up to 58,000 psi (399.9 MPa). The chamber for military 5.56×45mm NATO has a longer throat prior to the bullet contacting the rifling which results in lower pressures when firing 5.56×45mm NATO ammunition. If 5.56×45mm NATO is used in rifles chambered for .223 Remington the bullet will be engraving the rifling when chambered. which can increase pressures past SAAMI Max levels. NOTE: The C.I.P. standards for the C.I.P. civilian .223 Remington chamber are much closer to the military 5.56×45mm NATO chamber.
** The full-length LuckyGunner article is well worth reading. It even provides specifications for a number of .223 Rem reamer types, and compares the original .223 Rem, the 5.56x45mm NATO, and the modern .223 Wylde chamberings.
Put the same load in a variety of barrels (with the same length and chamberings) and you’ll see a wide variance in muzzle velocity. In fact, it’s not unusual to see up to 100 fps difference from one barrel to the next. We demonstrated this with a comparison test of Lapua factory ammo.
Chron Testing Lapua Factory Ammo
At our Southern California test range some years ago, we chronographed Lapua 105gr 6mmBR factory ammo in three different 8-twist barrels of similar length. The results were fascinating. Lapua specs this ammo at 2790 fps, based on Lapua’s testing with its own 26″ test barrel. We observed a speed variance of 67 fps based on tests with three aftermarket barrels.
Barrel Velocity Variance
Brand ‘S’ and Brand ‘PN’ were pre-fit barrels shot on Savage actions. Brand ‘K’ was fitted to a custom action. All test barrels were throated for the 100-108 grain bullets, though there may have been some slight variances in barrel freebore. With a COAL of 2.330″, the rounds were “jumping” to the rifling in all barrels.
Among the four barrels, Brand ‘PN’ was the fastest at 2824 fps average — 67 fps faster than the slowest barrel. Roughly 10 fps can be attributed to the slightly longer length (27″ vs. 26″), but otherwise this particular barrel was simply faster than the rest. (Click Here for results of 6mmBR Barrel Length Velocity Test).
IMPORTANT: Results Are Barrel-Specific, Not Brand-Specific
These tests demonstrate that the exact same load can perform very differently in different barrels. We aren’t publishing the barrel-makers’ names, because it would be wrong to assume that ‘Brand X’ is always going to be faster than ‘Brand Y’ based on test results from a single barrel. In fact, velocities can vary up to 100 fps with two identical-spec barrels from the SAME manufacturer. That’s right, you can have two 8-twist, 26″ barrels, with the same land-groove configuration and contour, from the same manufacturer, and one can be much faster than another.
Don’t Demand More Than Your Barrel Can Deliver
We often hear guys lament, “I don’t get it… how can you guys get 2900 fps with your 6BRs and I can only get 2840?” The answer may simply be that the barrel is slower than average. If you have a slow barrel, you can try using more powder, but there is a good chance it may never run as fast as an inherently fast barrel. You shouldn’t knock yourself out (and over-stress your brass) trying to duplicate the velocities someone else may be getting. You need to work within the limits of your barrel.
Factory Ammo Provides a Benchmark
If you have a .223 Rem, 6mmBR, .243 Win, 6.5×47 Lapua, 6.5 Creedmoor, 6.5×55, .308 Win, .30-06 Springfield, or .338 LM Rifle, we recommend you buy a box of Lapua factory-loaded ammo. This stuff will shoot great (typically around half-MOA), and it can give you a baseline to determine how your barrel stacks up speedwise. [Editor’s NOTE: The original test was conducted in 2008. The velocity of current-production Lapua factory ammo might be higher or lower, so your results may vary.]
When you complete a new 6mmBR rifle, it’s definitely smart to get a box of the factory ammo and chronograph it. That will immediately give you a good idea whether you have a slow, average, or fast barrel. Then you can set your velocity goals accordingly. For example, if the factory 6BR ammo runs about 2780-2790 fps in your gun, it has an average barrel. If it runs 2820+ in a 26″ barrel (or 2835 fps in a 28″), you’ve got a fast tube.
The way ambient temperatures, barrel heating, and powder warming can affect cartridge pressures (and hence velocities) was covered in a study Pressure Factors: How Temperature, Powder, and Primer Affect Pressure by Denton Bramwell. In that article, the author used a pressure trace instrument to analyze how temperature affects ammo performance. Bramwell’s tests yielded some fascinating results.
The better, up-to-date ballistics programs let you select either G1 or G7 Ballistic Coefficient (BC) values when calculating a trajectory. The ballistic coefficient (BC) of a body is a measure of its ability to overcome air resistance in flight. You’ve probably seen that G7 values are numerically lower than G1 values for the same bullet (typically). But that doesn’t mean you should select a G1 value simply because it is higher.
Drag Models — G7 is better than G1 for Long-Range Bullets
Popular Cartridge Types Profiled
From Wes (P1ZombieKiller): “[For my first PD trip] there are so many things I was not ready for. The one thing that I did bring (that no one told me about) was a canopy. I’m glad I did. Even though the weather was [near perfect], I know that sun can humble you real fast. With my pop-up canopy, I could shoot all day without getting killed by the sun. You had to tie the canopy down real well or the wind would blow it across the pasture.
Barrel Velocity Variance
