Weight isn't the impetus,projectile length is. Tough to beat the Hornie 75 BTHP as a default for everything,when suffering 9" RPM. Hint.
Slide the magbox shim,shorten bolt stop/ejector,add a smidge of exhaust port flare and nice thangs happen by default,with Lever' fueled Smooches crowding 3000fps. They are NASTY Little Fhuqking Hammers.
Hint...............
40/50's suck heavy ass,compared to the good stuff. Wind,impact velocity and transonic slips,if only as starters. Hint.
'Course I shoot it all and then some. Hint.
The Electric Chair(far left) is a Seven based 223AI 20" 10" RPM that'll fling 40's at 3950fps,which of course pale to 50's at 3700fps and they of course suck ass compared to a 75 at 3150fps,in the same chambering. Hint.
8" RPM as a minimum.
Deuces suck,especially in Retard Twist Rates. Hint.
Didn't last long and became a Hawk Hill 7" RPM 223 SALAMI for 88's. hint.
Just sayin'.
Thank me later.
Hint..............
LongTimeDumber,
Pardon your Emotions making less than zero fhuqks to me,or said rifles.
Hint.
LAUGHING!..............