What 7mm magnum cartridge to build?

[Mike Matteson]

I thought about I've run the 300 and 338rum for a couple of years now. And I think I'm looking for something that doesn't eat up as much powder.

You might look at chambering for a 300WM case but to 7mm. The 7mmRM is a little shorter to the shoulder than a 300WM case. I am not for sure why the 7mm RemM case is a little shorter to the shoulder.

 

[chav0_12]

Personally I'd do a PRC or a Nosler but the Nosler gets my nod. I have one and the only downside is the magazine length. So when the barrel is done I'll put a PRC barrel on it, then build another Nosler with more mag length.

 

[Justice1327]

You might look at chambering for a 300WM case but to 7mm. The 7mmRM is a little shorter to the shoulder than a 300WM case. I am not for sure why the 7mm RemM case is a little shorter to the shoulder.

The 7mm RM is built off the 338 WM case.
Highly recommend the 7mm Practical w/ 300 WM Long Brass

 

[JAYgs8163]

The fact that you can't find great 7WSM BRASS is upsetting. I would love to have one built myself.

Supposedly Bertram is coming back out with it. The prior importer went OOB. I've heard RavensRock may be the new importer for their brass and 7WSM is one of them. I've got a 7WSM and love it. Also I have 250 pieces of Bertram brass along with 150 new Winchester brass. Not selling any of my brass. A 7WSM on a long action is money!!

 

[6.5x300 WBY]

The 7mm RM is built off the 338 WM case.
Highly recommend the 7mm Practical w/ 300 WM Long Brass

I feel the McWhorter 7LPRC is one of the better designs. 300 prc necked down to 7mm. 300 prc is a better case than a 300 Win mag. IMHO

 

[MagnumManiac]

Don't know if this was already mentioned, but if you have a RUM 700, your only options are another RUM sized cartridge, RUM obviously, Nosler or another wildcat based on either of those.
PRC, Belted mag are going to put you into a feeding pickle if you try using them.
I like the 28 Nosler in a REM 700 with 3.7" mag length.

Cheers.

 

[FEENIX]

Have loaded for a couple of them for friends. And think the cartridge is awesome just burns a little more powder than what I'm looking for.

If you want to build a .284 cal because powder usage is an issue/concern, build a 7MM-08 or 7MM SAUM, but not with a RUM action. Again, as per my comment in #21.

If that's the route you want, sell or trade the action to a more appropriate action designed for your build.