Well, I will declare the paper patching of the big 454 bullets for the 45/70 a success, not a raving success, but for winging it, a success. I will definitely be working with them more in the future. In the Casull loaded in Casull cases worked well, the 355gr solids not so much, not sure what the deal is. The 330gr bullets from the Bullshop work just as well as they always have for the last 15 years. My big 350gr bullets, in an attempt to hit 2200fps, failed miserably, it must be my alloy, but they are yawing even at 30 yards. They work well with 2400 loaded to 1800fps, but not when pushed harder, going to try a slightly reduced charge of slower powder to maybe not put so much pressure on the base of the bullet. The Freedom Arms just seems to love the 335gr HPs and 330gr Bullshop bullets in 45 Colt cases. I regret I didn't get to shoot the 44 Mag, but I know it is accurate, it never fails me no matter what I shove in the case.

Dumb question but how does twist rate affect stabilization of this bullet at the speed you desire...? or are these regularly fired in similar guns...?

I shoot a 412gr at 1000fps and have no issues, I think it is just a matter of finding the velocity sweet spot.