Originally Posted by
hardcastonly
3031 IS FASTER burning,
(NUMBER 80 on the chart)
it will require LESS 3031 powder to peak at similar pressures faster.
52 grains of imr 3031 is a much higher pressure load than a similar charge of 4064 (number 96 on the chart)
Yes you're correct. I was reading the chart backwards (slower to faster). That would explain the thumping I took! But I was still in the "safe" zone with my Marlin because I referred to two different manuals which I normally do just as a precaution.
I just loaded up 10 rounds each of 49 and 51 gr of IMR4064 to see how they shoot compared to the 50 gr charge earlier. From a cold clean barrel, open sights, 60 yards the 50 gr load shot about 1.5". That might be as good as I'm gonna get which isn't all that bad.
I was doing some more researching on this and I think I'm also going to load a couple up with 45 gr of IMR4198 and try that.