I recently bought an upper assembly in 6.5 Grendel from JP Enterprises. I am really happy with the accuracy I am seeing so far (11 3 shot groups, 9 of which under an inch, in the aggregate the 11 groups of different charge weights with 2 different powders would all fit within 2") but I am a little disappointed with the velocities I am seeing so far. I have done two OCW strings with 123gr AMaxes: one with BL(C)-2 (I have quite a bit of that, in excess of 8 lbs) and another with CFE 223 (I have less than a pound now and no idea when I can get more).
With my BL(C)-2 string my highest velocity 2393 fps with 30.5 (that was the highest reading, my lowest was 2326 fps with the same charge weight). I got more consistent velocities with 30.2 grains clustered around 2370 fps. My Hornady says I should be seeing velocities of between 2400 and 2450 fps out of an 18" barrel. I expected something more out of a 22" barrel. My overall cartridge length was 2.25". The Hornady manuel had COAL 2.245".
One more thing. At 30.5.gr of BL(C)-2 I had one case that showed signed of pressure: there was like a black marker on the case head and what looks like a small gas cut on the primer. I saw the same thing with 31.5 gr of CFE 223.
I see that there is an Alexander Arms pdf circulating that has powder charges starting at a full grain higher and COAL's at about 2.265" and velocities up in the 2570 fps range. So does lengthening the COAL give you more leeway as far as powder charges go?
I plan on going to the range later on today. I have 10 rounds with 30.2 BL(C)2 at 2.25" and 10 more at 2.27" the plan being to clock them and do a 10 shot group each.
With my BL(C)-2 string my highest velocity 2393 fps with 30.5 (that was the highest reading, my lowest was 2326 fps with the same charge weight). I got more consistent velocities with 30.2 grains clustered around 2370 fps. My Hornady says I should be seeing velocities of between 2400 and 2450 fps out of an 18" barrel. I expected something more out of a 22" barrel. My overall cartridge length was 2.25". The Hornady manuel had COAL 2.245".
One more thing. At 30.5.gr of BL(C)-2 I had one case that showed signed of pressure: there was like a black marker on the case head and what looks like a small gas cut on the primer. I saw the same thing with 31.5 gr of CFE 223.
I see that there is an Alexander Arms pdf circulating that has powder charges starting at a full grain higher and COAL's at about 2.265" and velocities up in the 2570 fps range. So does lengthening the COAL give you more leeway as far as powder charges go?
I plan on going to the range later on today. I have 10 rounds with 30.2 BL(C)2 at 2.25" and 10 more at 2.27" the plan being to clock them and do a 10 shot group each.
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