What are safe pressure limits of handis & ultras.-45/70. I'm getting a new REAL stainless receiver 45-70 ultra. next anybody try the barnes blue tipped boat tail .458 bullets in 45-70? 300 gr. I've been searching for bullets with better bc's and actually the barnes original 300 gr. looks about the best. I want to stay in the 300 gr. or less category, but theres not too many choices. any thoughts welcome!