I own two rifles chambered for 270 WIN, they both get their best performance (velocity/accuracy) from handloads using H4831sc. A M-70 with the 130 grain Interlock and a M-77 with the 140 grain Interlock.
My .270 is a M70, also. I got the rifle in a trade with the intention of selling it, since it is right hand. My buddy said," Don't shoot it, if you intend to sell it". I shot it and now still have it. 60 grains of H4831 under the 130 Interlock is amazingly accurate and deadly on deer. IMR 4831 is there, also, however a bit slower speed.
I have enough ammo loaded with the IMRs, to last me probably the rest of my days-if I don't sell it.
