Best powder for heavy bullets in 300 RUM?

[1895Marlin]

I'd try 88.5g and 89.0 as well in your test .

Just going to narrow it down a bit. I'll work it up until I'm getting 1 hole at 100.

 

[FLSTFO2]

I had a can of RL25 on the shelf so I thought I'd give it another try . I made up 3 each of 89.0g, 90.5g and 92.0g to try kingbee's load. the 89 and 92 loads both grouped at +3" at 200yds. But the supprise was the 90.5ger that out shot my Retumbo load. I used cheap Hornady 208g hpbt's so as not to waste the AB's. going to try the AB's at 90.2, 90.5 and 90.8 and maybe get rid of the vertical.
And to think I had given up on the RL25.

 

[ivo]

RL 25 and H1000 are the go to powders for that calibre.

 

[1895Marlin]

I loaded 220gr nosler round nose with 3 each 84,88,92 and 94 gr of the retumbo. Hopefully report back on the weekend.

Well the 84 was an inch and a half, 88 little tighter, 92, 2 touching and 94 a clover. Probably about 5/8 MOA. At about 120 yds. I was going to refine it down a bit to go tighter but I think I'll just go with 94.


I was shooting against a cement block as a backdrop, in an old gravel pit no one knows about, and my groups of 3 were probably penatrating 8 inches into solid concrete. 220 gn bunker busters!

And my rifle will last way longer, these are slowed right down to 2950 FPS by the book.