You are going to hear alot of folks say you got to use Varget or 4064 or a midrange powder. But the fact is, most factory 270 is not loaded with such powder and I bet most bars and 7400's are not shot with such fast powder. They are loaded for accuracy and velocity and be under the pressure ratings. So I consider the slower powders just as safe. I think most of these stories that you have to use faster type powder comes from the M1 garand days. But the difference is M1's did use faster powder.

You won't reach your potential with 4064 or varget. I suggest the same thing you would use with a bolt with exception of real slow powders like RL22 or H1000.

I load my semi with 55gr of 4350 and 130gr gameking. Great cycling. Around 2970ft/sec, and very accurate. I started using IMR4064, and the gun's velocity and accuracy was horrible. So I moved on up.

Sure you might have trouble with RL22 or H1000 cycling, but those are darn near compressed loads. Most factorys are not compressed unless you saying light magnums.