Home Forums Hunting & Shooting Gunsmithing Re-chambering 7mm RM

Hey guys,

Dumb question but what are my options for re-chambering a 7mm RM in a 700 LA. Can i go to a 7mm Weatherby in particular? Any recommendations on who to do the work if at all possible?

7 mm Weatherby has larger base diameter than 7 mag. One of the reasons I chose 7mm Wby to rebarrel from .300 Wby was they have the same base diameter -- no need to change the bolt at all. Whatever you do, be sure to NOT get the two 7 mm ammo boxes mixed up. Have the barrel remarked. Don't know a thing about a 28 Nosler, but maybe (???)

Mashburn

7mm Wby has the same .532 nominal base as all belted mags. But, you would have to take the barrel back a bit to get the chamber to clean up. You could get near the same results by long throating your 7 Rem Mag.

For any meaningful gain you could go Mashburn , STW or RUM....but you would have to describe "meaningful" before reaching into the reamer box....:-)

YMMV

Are you trying to rechamber a factory tube or going new aftermarket barrel?

Well both are good 7mm options, but the difference in capacity between the two is 2-4 grains of powder...so there is not much there to be gained.

The Rem was well-designed from the outset. The Wby can be run a little hotter because of the freebore inherent to the design, but the Rem has enough capacity to drive today's better bullets fast enough to handle about anything that needs to be done, so if I happened into a rifle chambered for one I wouldn't bother to switch to the other.

Again, with maybe 4 grains difference between the two...if I thought I needed more bang, instead of spinning my wheels for such a small gain I'd consider the money better spent toward a new rifle in a bigger case like the 28 Nosler, and throw a faster twist into the mix.

The Nosler doesn't even have to be run at full max to overshadow them both, but there's nothing wrong with the 7RM.

Hey Guys,

I know there is nothing to be gained here...i simply have always wanted a 700 in 7mm wby...simple as that. Looking to re-chamber, not replace a factory Remington 700 7mm rm barrel to 7mm wby.



This is false...base diameters are the same.

You might be able to locate a Rem 700 Classic in 7mm Wby. I had one briefly years ago.

It was the Classic chambering in 1991.

There are two of them on gunbroker right now

Here is one of them
https://www.gunbroker.com/item/765570680

As far as case design is concerned, I like the 7mm Weatherby much more than the 7mm Remington. Although case capacity is the same, the longer neck of the Weatherby makes it easier to work with. The throat should have been made longer in the Remington Mag from the outset and it would have been a nicer cartridge. The Weatherby throat should be made shorter. In the end, the cartridge case is a powder container and a high pressure gasket. It's easy to wonder why people obsess over the designation stamped on the barrel. GD

0.5215" and 0.5200" are only practically the same measurement. I got mixed up. Let's just say you win. Enjoy!!

Another choice would be the 7-300 Wby. That would clean the existing chamber without setting the barrel back. It started life as a wildcat but I think it is factory loaded now.

The 6.5x300 is factory now but I am not aware of the 7x300 being legitimized. I am with the others all you would gain is expensive brass. I would go Mashburn, 7x300 WM or the 7x300 Weatherby or most likely shoot it as is.

Ream that thing out to 28nosler and rock on, 28 reamer will clean up a 7 mag chamber easy... ask me how I know.

7mm STW is an option.

I like 7mm RM's though.

I like 7 Rem mags also, I have 4. You can’t beat one for power with little recoil.

Don't know what you have in mind but I have a new in shipping tube Kreiger 7mm, 5R, light weight, chrome moly blank, Kreiger wouldn't do light contour in stainless, that I have $410.00 into that I'd let go for $250.00 plus shipping. Don't know if that would be an option or not.