6BRX Barrel Life and Long-Term Accuracy
For the past year, Forum member John Skowron (John708) has been campaigning a 6BRX, built by Nat Lambeth (RustyStud). You’ll find the full history of John’s 6BRX project in this Forum Thread. With this rifle, John was the overall 1000-yard winner at Butner in February 2007.
The 6mm BRX is based on the 6mm BR cartridge. The shoulder is moved forward, but the shoulder angle and case taper is the same as the parent cartridge. This way you can use standard dies for most purposes (although it is a good idea to have a custom full-length die so you can size the entire case body). Many of our readers have been interested in the 6mm Improved (BRX, Dasher etc.), but they’ve wondered about case durability and barrel life. John has answers for those questions:
6BRX Case Life
Case life running the Berger 105s at 3000+ fps is 14-15 reloads. Brass was discarded when the primer pockets became too loose. The 6BRX brass OAL after fireforming is 1.56″. Max OAL for the 6BRX is 1.58″. The brass never stretched enough to require trimming before discard. Anouther plus for the 6BRX and Lapua brass.
By the way don’t even bother with Remington-brand 6BR brass. The primer pockets were so loose after my standard fire-forming load I had to trash all the cases. Stick with the good stuff, Lapua.
6BRX Barrel Life
I now have 2570 rds through my 6mm BRX. I was just at the range today doing an accuracy test. I shot two 10-shot groups at 100 yards, one with 105gr Bergers, and the other with 107gr Sierras. Both were identical 0.44″ groups. Not bad for a rifle with 2500+ rounds through it.
Achieving this barrel life goal pretty much completes my 6mm BRX project. I’m now shooting a cartridge that has the same or better barrel life than the 260 Rem, it’s more accurate, with essentially equal wind drift. I’ll continue to post updates on barrel life. I think this barrel will last for another several hundred rounds.
Heavier Bullets
As far as shooting the DTAC 115s goes, I’ve temporarily abandoned that effort. The 105 Bergers, running 3050-3100 fps, give up very little wind drift to the 115s running at 2900-2950 fps. You might potentially get 3000 fps with the 115s using H4350 and throating the chamber to seat the bullets out. But since I very happy with the 105s and the way they’re performing at long range, I’m not going to change for now. [Editor’s Note: The Berger 105s in John’s latest reports were lot #559, from Berger’s new die.]
Is there something like a too short case oal??? Mine is currently 1.51.
Regards
Hello, I am interested in the 6mm BRX. I reload and like the idea. Is there a standard reamer that I can purchase, or find a gunsmith that has the correct reamer? Also, does the OAL increase as well? I live in Michigan and I have ordered custom guns and calibers, but not completely independant so to speak. If you have any information on reamers, gunsmiths, and matching dies I would greatly appreciate it. Mark Skynar
Mark:
Dave Kiff holds a copy of John Skowrons’ 6mmBRX reamer print. There are several other shooters 6mmBRX reamer prints available. I know Dave Manson, and DClymer also have prints of the 6mmBRX.
The primary varibles are Throat length, and neck diameter. John Skowron chambers have a .271 neck and he does not neck turn. He is using a .265 or .266 bushing.
A .272 neck also is considered a no neck turn chamber.
I have done a number of 6mmBRX with .268 necks. with .262 – .264 bushings
I know folks who have their reamer ground with only .020″ throat and custom cut their own throats with a throating reamer.
Other use .090, .104, .120 throrat
If you are going to have a reamer made send the reamer maker a resized case with the bullet seated to the depth you desire. Include your measurements with it. That way the reamer maker can check your measurement against his.
there are many dfolks on 6mmBR who have taken the plung and built their own 6mmBRX. All can provide you with good information.
Learning from my own mistakes. Don’t over size the brass just bump the shoulders.
Don’t try to shoot is at extreme velocities. The 3025-3080 fps node will gain you accuracy, ecconomy, and longevity.
Good Luck with your project.
Nat Lambeth
I have one question, were these barrels put through the Melonite process? If so by what company because there several that advertise and it’s a crap chute at best.