I have been building some rounds for a 1-9" twist, 16" AR with a wilson barrel.
I worked up to (24 Gr. H335) which seems to be a pretty good lower powered load for me. But using the new to me Hornady 55 Gr. fmjbt has been difficult. I have read they edge out the Win 55 Gr. fmjbt in accuracy so I picked up about 500.
AT 100 yds, until today I was getting 3.342- 3.780 Inch groups. (very sucky)
I worked up from the recommended 2.200 COAL and ended up at the 2.600 … But something really funky happened. When I started in on the 2.258 rounds I must have hit a sweet spot. The group was a 3 round .498 with one flyer. I repeated this again with a .487 group!
I literally was going up from 2.200 - 2.205 - 2.210 - 2.150 - etc…
The reason I was using 2.258 was that these rounds ogive didn’t bring them up as far as the other 2.260’s so I set them aside as an odd loading.
Any ideas why 2.260’s sucked but 2.258’s didn’t? I’m stumped.
Brass: FC Military de-crimped by me. and all trimmed to 1.750
Fed small rifle primers #205
H335 powder @24 Gr.
Hornady .55 Gr fmjbt
C.O.A.L- various 2.200 - 2.260
Wilson 16" barrel
Bushnell sight 1X32