450 Bushmaster with Buffalo Rifle

Good morning
Bought a couple 8 pounders of Buff Rifle back awhile as it was cheap and is like the old 5744 was.
So started running it in the new to us 450 Bush. with a 250 grainer.
Ran a ladder test and got to 41 grains before our rifle finally stove piped. No pressure signs yet......
But a thinking with the 16 inch gas system maybe some slower powder as we do not need a 250 grainer cooking along at more than 2000 fps for yotes and other small critters here in east ILL-Noise.
Question is how much slower powder to get a smidge more bolt pressure.

I don’t think you’ll get more pressure out of a slower powder - it is after all, a straight wall case. Going to a 300 grain bullet will give you less velocity, if that’s what you want. You have 16 lbs of that powder, why switch? I confess I’m having a little trouble following the logic here.

Good point on the straight wall case.... Thanks 26Charlie
When we get back home area I will move on up the scale.