I've been reloading for over 35 years, bolt guns and revolvers/pistols. Now, due to prices, I have started to load for my 1:9, 24 in barrel varmint AR in 223.
In the past, I was shooting blue box Black Hills 60 grain V-max and getting 1/3 MOA at 3000 fps. I've tried to duplicate that load using Hodgdon and Nosler data with both V-max and Nosler BT's with Benchmark, Varget, TAC, mag and non-mag primers. Groups were terrible and speed was no better than 2850-2900 fps. I switched to Nosler 55 grain BT's with Benchmark and non-mag primers. I finally got a good group (1/2 MOA) but speed was no better than 2980 at listed max loads.
With those speeds, I might as well go to the 69 grain match bullets for small critters. Hopefully, they will reach book speeds. BTW, I had the barrel scoped and all seems fine.
What the 'ell am I doing wrong? Is the gas system and twist taking that much speed off? Suggestions?
TIA.