fdbyrne78 Wrote:I went back to the range tonight and shot 25.6 up to 26.0. 25.6gr still showed ejector marks and chrono'd at 2410 fps. Still single digit ES's all the way up to 26.0 with reasonably small groups even though I was shooting fast to get my shots in before it got dark. I'll load some more up and go lower still until I don't see any more marks.
I know that I could get more velocity with CFE or Lever but I've not had good results with either. I love the accuracy of AR Comp but I have a feeling that by the time I find a load that doesn't damage the brass that I really won't be very happy with the velocity. I'm averaging almost exactly 20 fps difference for each .2gr change in charge weight. If that holds on the way down then going to 24.6 would put me at 2310 fps which to me is disappointing in a 20" barrel. Maybe I was expecting too much.
I had intended to shoot a few with the gas turned off as suggested but I didn't bring enough ammo and at this point I'm pretty sure it isn't a gas issue. I might still try it the next time I get to the range.
Accuracy, by and large, is a function of harmonics/barrel timing.
Find an ignition system, (powder/primer combo), that gives you the best speed with lowest ES/SD and lack of pressure signs. Then adjust your seating depth to find an acceptable accuracy node.
Working within the confines of a max COAL mag length and jamming the bullet down into the cartridge reducing powder capacity complicates things but, accept the challenge!
