First time casting for my AR15 (Windham Weaponry AR15 5.56 1 in 9 twist) using a Lee C225-55-RF mold and bullets gas checked and sized to .225".
I do cast for several handgun calibers.
I did some load testing shooting five shots each with Win 748 powder at 22.0 grn. to 25.0 grns. at .5 grain intervals, and using a chronograph, rifle scope and bench rest.
I checked zero at 75 yards with my standard FMJ reloads (25.8 grn. Win748 @ 2.250" COAL) and then started my lead cast load testing.
The groupings were all over the place with some not hitting the paper target (8-1/2" x 11").
I might get two, maybe three on paper but that was it and the grouping was around 10 inches or so.
After shooting the 23.5 grain loads and still having bad groupings I checked the scope mounting and it was tight so I checked zero again with my standard loads and it was right on.
I went all the way to 25.0 grains with the same terrible groupings and not all hitting the paper. Re-checked zero again - OK.
Velocity at 22.0 grains = 2224 fps avg. and at 25.0 grains = 2655 fps avg.
No leading at all.
I'm puzzled!
The cast bullets are tumble lubed with Lee Liq. Alox.
Should I wipe any lube off of the seated bullets in case that is causing problems?
The bullet has a flat point compared to pointed on my FMJ reloads.
Anyone have success with the C225-55-RF cast bullet?
Tips, advice, suggestions???
Thanks