Finally got my hands on a bit of AR Comp (Thanks ONT001!). Did a pressure work up with the Pressure Trace system with both AR Comp and Varget since I have quite a few more rounds on the barrel since the last Varget temperature test. Barrel is a 26" Barlein 5R 1-11.25 twist with a little over 7500 rounds on it.
Work up both powders and a 190 SMK in 1 gr. increments, plotted the data and put a trend line to it. The powders give the following velocities at 62,000 psi:
Varget: 2768 fps.
AR Comp: 2706 fps.
AR Comp seems to be faster buring.
I loaded them to the same velocity for the test. I just used the Varget load I was using in my 22" barrel and matched the velocity with AR Comp. It takes about 2 gr. more with AR comp to get the same velocity.
AR Comp is indeed temperature stable, twice as good as Varget (0.09 fps/F vs. 0.22 fps/F). Varget results matched my previous test results, which was with a different lot. AR Comp has nice small kernels that meter and dispense very well. I had an SD of 6 (all shots across temperature) with loads dispensed from my tuned Chargemaster.
I didn't shoot any groups with this, it was all into the berm. So, I can't comment on groups, but I am going to play with this powders some more. The only thing I did notice was that a bit of a concern was that the 210M primers seemed to have trouble igniting it. There was always a noticeable delay before pressure rise in all of the traces.
Work up both powders and a 190 SMK in 1 gr. increments, plotted the data and put a trend line to it. The powders give the following velocities at 62,000 psi:
Varget: 2768 fps.
AR Comp: 2706 fps.
AR Comp seems to be faster buring.
I loaded them to the same velocity for the test. I just used the Varget load I was using in my 22" barrel and matched the velocity with AR Comp. It takes about 2 gr. more with AR comp to get the same velocity.
AR Comp is indeed temperature stable, twice as good as Varget (0.09 fps/F vs. 0.22 fps/F). Varget results matched my previous test results, which was with a different lot. AR Comp has nice small kernels that meter and dispense very well. I had an SD of 6 (all shots across temperature) with loads dispensed from my tuned Chargemaster.
I didn't shoot any groups with this, it was all into the berm. So, I can't comment on groups, but I am going to play with this powders some more. The only thing I did notice was that a bit of a concern was that the 210M primers seemed to have trouble igniting it. There was always a noticeable delay before pressure rise in all of the traces.
