Reply with quote #25
Pierced primer problems, and new load testing.
I've been having problems lately with pierced fed 205's behind 32.5 grs of Varget and the 105 Bergers. This load has always caused an occasional pierced primer. This hasn't been a problem up to now as my primer pockets have always been tight. I got 15 reloads out of the Lapua brass before the primer pockets started to loosen.
I think the problem is related to either a batch of slightly softer brass, or some throat erosin raising pressure slightly. Before playing with JB bore compound or Tubb's throat maintance system, I thought it would be prudent to go back to the harder cups of the CCI br-4's. I did a ladder test with H-4350 and the CCI match primers in my current rifle. The velocity data is listed below:
34 grs-3030 fps. 34.5 grs-3066 fps. 35.5 grs-3110 fps 36 grs-3145 fps. There were no pressure signs or pierced primers with these loads. I shot a 5 shot group with both 35.5 grs- .37in at 100 yds. and 36 gr. .45in at 100 yds. I'm going to test the 35.5 gr. load against my current long range load on Sat. I'll post the results when I done testing.
Reply with quote #26
Great thread John!I really like the performance of the 6brx. Keep us posted how it goes with 115. You think you can get it around 3000f/s?
Reply with quote #27
Yes, Please continue. Great thread and info...
Reply with quote #28
6BRS Load Testing update:
I shot some 10 shot groups at 100 yrs. yesterday, comparing 35.5 grs. of H-4350 vs 31.5 grs. Varget (my standard comp. load). The 4350 load was behind CCI -br-4 primers. Both loads were shot with Berger 105's jammed 15/1000's in.
The Varget loads consistently grouped in the .4's at 100 yds. The 4350 loads would shoot really well for 8-9 shots, but in that group there would always be 1-2 flyers, opening the group up to .6-.7 range. So I'm staying with Varget and Fed. 205's until the barrel burns out.
As far as shooting the 115's goes, I've temp. abandoned the project. The 105 Bergers, running 3050-3100 fps. gives up very little wind drift to the 115's running at 2900-2950fps. You might potentially get 3000fps with the 115's using H-4350 and throating the chamber to seat the bullets out. But since I'm very happy with the 105's and the way their performing at long range, I'm not going to change for now.
Reply with quote #29
Thank you again for the update! I see your point with 115s and agree. Running 105 at 3000+f/s is very competitive. Now, at that velocity, what is the life of the brass?
Reply with quote #30
6BRX case life questions answered.
Case life running the 105's at 3000fps+ is 14-15 reloads. Brass was discarded when the primer pockets became too loose. The 6BRX brass OAL after fireforming is 1.56 in. Max OAL for the 6BRX is 1.58 in. The brass never stretched enough to require trimming before dischard. Anouther plus for the 6BRX and Lapua brass.
By the way don't even bother with Rem. 6br brass. The primer pockets were so loose after my standard fireforming load I had to trash all the cases. Stick with the good stuff, Lapua.
Reply with quote #31
Brass life is as good as it gets. Great news!
Reply with quote #32
6mmBr project update
I now have 2570 rds through my 6mm brx. I was just at the range today doing an accuracy test. 2 10 shot groups, 1 with 105 Bergers, and the other with 107 Serria's were shot at 100 yds. Both were identical .44 in groups. Not bad for a rifle with 2500+ rds 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 anouther several hundred rds. I'm also in the process of working up loads for a second 6mm brx. I will post that data when it becomes available.