I have a Texan .510 LSSCF, and the stock rifle with pressure at 3,600psi would sling the 255gr Mr. HP slugs at 1,005fps. Same rifle today, set at 4,400psi is slinging Mr. HP 305gr slugs at 1,049fps. The heavier 385gr Mr. HP slugs are going 954fps. lol... the 255's are at the ragged edge of...