Norma is now making RUM brass?!?!

[Camshaft]

That says it all.

There is one thing that everyone needs to know about the 7mm RUM. It is .004 thousandths
longer in the body and .018 longer at the neck shoulder junction.

So It requires sizing down (Bumping the shoulder) .004 thousandths before it will chamber in
the 300 RUM.

300 Rum Brass is scarce and 7mm RUM is also but it can/will be available some day.

The only other option is to buy the managed recoil ammo from Remington for $35 to $40.00
and shoot it for break in or fouling shots and end up with fire formed brass in your chamber for
very little more than the price of brass.

J E CUSTOM

If the 7rum is slightly longer in the body and neck then why wasn't it the case of choice for the 338edge? Or is the different insignificant?

 

[J E Custom]

If the 7rum is slightly longer in the body and neck then why wasn't it the case of choice for the 338edge? Or is the different insignificant?

Its only .004 thousandths longer to keep someone from sliding a 300 RUM cartridge in the
Big 7mm RUM and having a catastrophe. But that is insignificant in case capacity.

The 375 RUM on the other hand is the same size and after sizing you can turn the necks
down and have very uniform brass for the 300 or the 338 Edge.

In fact if I were going to build a 338 Edge the 375 RUM is the brass I would use to avoid
any neck thinning.

J E CUSTOM