Thread: 7mm RM rechambering

Originally Posted by Spitfire

Some good advice above.

T3s are great donors for custom or semi-custom builds, but not ideal for magnum cartridges. The action is not really strong enough, the magazine is too short, the barrels too thin and the recoil too stout. The max OAL you will be able to extract an unfired round is 3.5” in a T3.

As others say, the ELD-M 180 in your 7 RM would be the go, but you will need to forget mag feeding. Powders like RE26 and 33 will fix you up. If you want to go .30 cal you will need to be in the 230+ grain projectile range to match the 180s and recoil will be stiffer.

Do you have a reason for wanting a non-belted magnum? I keep reading about blokes who want this but they rarely seem to know why other than reading that belts are superfluous. A belt is not an issue at all and the case only headspaces off it on the first firing anyway.

It’s your choice and you should have what you want, but the T3 isn’t the best choice for your project.

BTW - I have a T3 based .300 Win Mag and it’s good, but not ideal.

Now I could say that the belted magnums don’t like being FL sized and end up with case separation due to work hardening... but I’d be full of s****. Honestly, i don’t like the belt purely because of looks... shallow I know!

And I know the T3 isn’t ideal, but it’s what I have, and what I’ll use.