I bought an eight pound jug of MP-665 and a jug of MP-667 , looking at the load data for 300WM the charge weight looks really close to 4831. Am I safe to assume I could apply the same logic to charge weights for 7mmRM?
I rarely if ever post on any form because I can usually find an answer using the search function but I came up empty handed on this one.
Thanks in advance for any advice.
You will be in uncharted territory for the 7MM Mag. You can test it, but start really low @ 4831 data and go up from there. Use a chronograph to see where you are at in velocity and keep good notes. If you're careful, you won't hurt yourself or your Rifle.
Some years ago, I bought a bunch of WC852 surplus ball powder that was used for the M1 Garand and used it for some M-2 ball equivalent ammo. It has a burn speed around H-380. I tested it in the 270 Win. using H-380 data and got good results by starting low and working up. It was useable in the 270.
About 5 years ago, I had some of the IMR 4451 Enderon powder that has been discontinued. I wanted to use it in the 270 Win. with the Barnes 110 TTSX. There was no loading data available at all for that bullet weight. I started low and finally arrived at a load of 58.0 Grains @ 3250 FPS with no pressure signs. It shoots 1 MOA out to 300 yards and it is my go to Deer / Antelope load. A very good load from uncharted territory.
