alucard0822
For great Justice
I have been shooting the 300 BO for some years now in a 16 inch carbine gas set up. I have no problem using standard SR primers with h110 or Lil Gun. In .44 Magnum pistol, I use magnum primers to get better burn efficiency but I have never had a problem in the 300BO. Perhaps pistol gas setups and pistol length barrels may need magnum primers but I don't see the need in a carbine.
Was getting some vertical stringing, and about 100fps variance with CCI400 and CFEBLK out of 110, 150, and 208gr(sub), worst was with 150gr supers, CCI450 magnum primers cured it, and shrunk the group size noticeably. I am shooting/testing out of a 9" with pistol gas, so that may be some of the difference. Already switched to magnum primers when working up H110(110-150gr) and A1680(150, 208, 220plated), and both powders did fine, but being I never loaded them with std CCIs, I don't have standard primer data to compare them to. In the past with H110 in nuclear 357mag loads for my 16" lever Carbine(similar loads to 300BO), I had no problem in the summer when working up the load, but groups opened up, mostly vertically when shooting in the fall/winter, switching to magnum primers cured that too.