September 20th, 2014

Life Lesson: Every Barrel is Unique. Same Load Registers 4 Different Velocities in 4 Different Barrels

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, 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 speed testing

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).

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, 6BR, .243 Win, 6.5×47 Lapua, 6.5×55, .308 Win, 30-06, or 300 WM 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. When you complete a new 6BR rifle, it’s wise 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.

Permalink Gunsmithing 8 Comments »
September 20th, 2014

Slow-Motion Video Shows Bullets Pass Through Muzzle Brakes

Proof Research High speed photography muzzle brakeIf you want to see how a muzzle brake really works, definitely watch this remarkable slow-motion video compiled by Proof Research.

This amazing video features a variety of firearms: suppressed 9mm pistol, .338 Norma rifle, .300 WinMag rifle, 12ga comp’d shotgun, plus an AR15 and AR10.

This Must-Watch Video Has Some Amazing Ultra-Slow-Motion Segments

Watch the ultra-slow motion segment at the 2:55 mark and you can actually see a .30-cal bullet spin its way through the muzzle brake, leaving trail of flame that blows out the ports. Interestingly, at the 3:10 mark, you can also see a bright “afterburn” ball of fire that forms a few inches ahead of the muzzle milliseconds after the bullet has left the barrel. Perhaps this is late ignition of unburned powder?

Video Time Line (Test Firearm Segments)

  • 00:23 – 00:53: Walther 9mm PPQ Pistol, Osprey 45 Suppressor
  • 00:54 – 01:44: Proof Research .338 Norma Rifle, Carbon-wrapped Barrel, 3P Muzzle Brake
  • 01:45 – 02:22: Remington 870 12ga Shotgun, VangComp Ported
  • 02:23 – 03:40: Proof Research 300 WM Rifle, Carbon-wrapped Barrel, 51T Muzzle Brake
  • 03:41 – 04:14: AR15 (M16) Rifle, Vltor A5-A5H2 Buffer
  • 04:15 – 05:23: AR10 .338 RCM

Proof Research High speed photography muzzle brake

Proof Research (PR) sells high-grade hunting and tactical rifles built with PR-made actions and carbon-wrapped barrels. For more information, visit ProofResearch.com.

Credit Steve of TheFirearmBlog.com for this YouTube video. Footage by JNZ for Proof Research.

Permalink - Videos, Bullets, Brass, Ammo 3 Comments »
September 20th, 2014

New Hard Air Magazine Website for Air Rifle Shooters

Given the high cost of reloading components, and how difficult it is to find rimfire ammo these days, many shooters are looking seriously at air rifles, at least for short-range training and plinking. Air rifle shooting is quiet and fun. Plus there is a virtually inexhaustible supply of free air on the planet. Airguns are increasing in popularity for many reasons including cost factors, powder and ammo shortages, and tighter restrictions on centerfire guns. How popular have airguns become? Consider this — it is estimated that over TEN MILLION airguns will be purchased in the U.S. in 2015. That’s a huge number.

If you’re interested in air-gunning, there’s a new resource that covers air-gunning from A to Z. Hard Air Magazine is a new, one-stop destination for everything airgun related. The free online magazine is devoted entirely to airguns and associated products. Unlike other airgun media, Hard Air Magazine is not tied to one distributor or manufacturer. “We cover the entire spectrum of products through objective editorial, illustration and videos,” says Hard Air founder Stephen Archer.

Hard Air Magazine

Team of Expert Airgunners Provide Product Reviews
Many consumers research their airgun purchases on the Internet. Helping consumers make smart purchases is the mission of Hard Air Magazine. Archer explains: “Our goal with Hard Air Magazine is to offer balanced, instructive information to people purchasing airguns and accessories. Fact-based, detailed product reviews are at the heart of Hard Air Magazine. We’ve put together a phenomenal team of product testers with over 100 years of combined experience in airgun shooting. These are genuine enthusiasts who have spent their lifetimes shooting airguns and truly understand what makes one better than another.”

Hard Air Magazine

Permalink New Product, News No Comments »