Only bottleneck cartridge I load for, and done very little of it (under 100 rds). Only other calibers I load are 9mm and 357.
Loading everything with Lee single stage breechlock challenger, Lee dies (2 die set with FCD bought separately)
55 gr RMR FMJ-BT with cannelure
26.4 gr TAC (within the 5.56 mil spec load data from Western)
Mixed range brass, decapped, wet tumbled with ss pins, rinsed, dried, then sized.
CCI 400 primers
seated to cannelure and crimped with Lee FCD
25 yards at a bench, support hand resting on a bag, buttstock shouldered -
M&P Sport, 16" 1:8 barrel
5 shot group - 1 7/8" with a 3-9 scope at 3x settting; 2" with a 3 MOA red dot on a 45 mount
compared to -
ZQI M855 NATO spec
5 shot group - 7/8" with the same scope. I put the first two in the same hole and got too excited...
I've loaded from 25.6 to 27 gr in 0.2 gr increments with similar poor results. This was before I got the FCD (just delivered yesterday) Neck tension always seemed ok, as I could press any round into my bench top without moving the bullet. No idea what I 'm doing wrong. Only thing I can think is to drop down into .223 pressure load data and see if things tighten up. But I just don't know why I can't at least come close to the mil-spec stuff I have on hand. It's a different bullet, 62 gr penetrator vs 55 gr FMJ, but that shouldn't mean grouping this poorly.
Loading everything with Lee single stage breechlock challenger, Lee dies (2 die set with FCD bought separately)
55 gr RMR FMJ-BT with cannelure
26.4 gr TAC (within the 5.56 mil spec load data from Western)
Mixed range brass, decapped, wet tumbled with ss pins, rinsed, dried, then sized.
CCI 400 primers
seated to cannelure and crimped with Lee FCD
25 yards at a bench, support hand resting on a bag, buttstock shouldered -
M&P Sport, 16" 1:8 barrel
5 shot group - 1 7/8" with a 3-9 scope at 3x settting; 2" with a 3 MOA red dot on a 45 mount
compared to -
ZQI M855 NATO spec
5 shot group - 7/8" with the same scope. I put the first two in the same hole and got too excited...
I've loaded from 25.6 to 27 gr in 0.2 gr increments with similar poor results. This was before I got the FCD (just delivered yesterday) Neck tension always seemed ok, as I could press any round into my bench top without moving the bullet. No idea what I 'm doing wrong. Only thing I can think is to drop down into .223 pressure load data and see if things tighten up. But I just don't know why I can't at least come close to the mil-spec stuff I have on hand. It's a different bullet, 62 gr penetrator vs 55 gr FMJ, but that shouldn't mean grouping this poorly.