Tried some 110gr V-Max loads this am and the results were cornfusing.
RIFLE- Aero M5 build 16" MLG Ballistic Advantage SS barrel, SLR Adj. Gas Block. Leupold 1.5x6 MK IV. Rifle groups various ammo very well. Up until today, has always functioned just fine. Shoots factory Hornady 110gr TAP well.
I loaded 110gr Z-Max bullets using both TAC (48.0/49.0/50.5) and AA2520 (51.5/52.5/53.5). I expected both to do ok but surprisingly the TAC was a flop function wise.
The three loads I tried in TAC were problematic as far as functioning and I tried adjusting the GB back and forth with no success. Groups were good but rifle won't function 100%. The lightest loads at 48.0 functioned half-ass. None of the loads resulted in last round bolt lock back
The loads with AA2520 were outstanding. They cycled with authority at 3:00 at five to six feet. Bolt locked back every time. The best group was 52.5 with 51.5 a close second. I'm sure I can dial down the gas but it was working so I left it alone for today's trip.
I looked at the powder burn rate chart and saw TAC is faster, I assumed a faster powder would result in better gas function as the charge would be burned completely, or more completely, thus better gas volume. I assumed, perhaps wrong, that a faster powder burn would be better for lighter faster bullets due to decreased dwell time.
Do I have it backwards? Never played with lighter bullets in the .308 gas gun up until now. The rifle loves the 110gr Z-Max/V-Max and they are great on hogs and coyote, that's why I'm loading for them.
Comments? Opinions?
52.5grs AA2520 110gr Hornady Z-Max