codyadams
Well-Known Member
I finally got a chance to do some load development with the 143's in my 260 AI. 30" 1 in 8 twist 4 groove Krieger barrel. These are the first groups with these bullets through my gun, they are loaded .010" off. Using H4831sc I shot the 5 shot groups first in .3 grain increments from 47.6 to 48.8 grains, then narrowed my loads down to .2 grain increments from 48.2 to 49 grains shooting 3 shot groups. Used sorted Remington fireformed .243 brass because I had 300 of them laying around.
At 49 grains, I had no heavy bolt lift, no extractor mark, and excellent accuracy, as you can see. Didn't have my chronograph with me, but I'll chrono them on my next days off, I think I'm gonna do my next loads at 48.6, 48.8, 49, and possibly 49.2 grains with 5 shot groups and see if I can get this narrowed down more.
At 49 grains, I had no heavy bolt lift, no extractor mark, and excellent accuracy, as you can see. Didn't have my chronograph with me, but I'll chrono them on my next days off, I think I'm gonna do my next loads at 48.6, 48.8, 49, and possibly 49.2 grains with 5 shot groups and see if I can get this narrowed down more.