I was wondering if anybody else uses IMR4320 in there 458 Lott. I loaded some solids with 85gr of this powder. Shot 3 of them to get the velocity. It seemed like a very powerful load.
I was thinking it might be to hot. What do you think?

When I was using 4320 I was running 81 grains with a 450 gr. bullet. If you are using a 500 gr. bullet I would think it would be on the hot side.

Ray Atkinson use to promote 4320 as the powder for the 458 Lott and as the only powder that would get the top ballistics with the 500 grainers. He also use to refer to the top gunsmith David Miller also recommending 4320. I think David Miller might have done the 458 Lott at the start.

But if you search on the African forum for 458 Lott/Atkinson you will probably turn up the load Ray recommended.

I got 2260fps with 81gr and a 500gr molly coated TSX,from my factory CZ..I did not try to go further but I think I could go to 82gr.I would check my cases over for signs of high pressure like loose primer pockets.

Thanks you guys.