Home Forums Hunting & Shooting Ask The Gunwriters Something I've never heard before.........."seating depth first"

We used to see that while determining loads for specialized applications. Identical MVs, with the OAL adjusted so that the internal volume is identical.

Barnes 130 gr copper bullet

IMR powder 4895 had an exit velocity of 2750 fps and a barrel time of 1.139 ms. PMax - 40,669 psi
IMR powder 4064 had an exit velocity of 2750 fps and a barrel time of 1.080 ms. PMax - 43,527 psi

Hornady 130 gr cup and core SP

IMR powder 4895 had an exit velocity of 2750 fps and a barrel time of 1.145 ms. PMax - 40,132 psi
IMR powder 4064 had an exit velocity of 2750 fps and a barrel time of 1.109 ms. PMax - 43,086 psi

Check the Pmax for the two powders as they relate to the barrel time.