7mm Mag Rechamber
- Thread starter jsmitt6
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adam32+P
Well-Known Member
7mm mag is better than anything else, no reason to change it unless you just wanna be tacticool.
huntinfool18
Well-Known Member
28 nosler, 7/300 win, 7 stw, 7 wby, 7 rum, 7prc.
Depending on how much you can cut off you could do 7 saum, 7 wsm
Depending on how much you can cut off you could do 7 saum, 7 wsm
Huntaddict
Well-Known Member
Agree
Need to know more about the bbl. The amount you cut off matters for sure. You need to measure your shank length. Then consult with your smith on what your options are
If you are dealing with a stock Rem shank length of around 2 inches and a standard sporter barrel, going to be tough to get to the Medium and small calibers - probably have to stay in the LA magnums and even then, you may be close
MagnumManiac
Well-Known Member
7STW is the bees knees…
Cheers.
Cheers.
A 7/300WM would be cool.
adk hunter
Well-Known Member
First thing I'd do is check the throat or measure where the good rifling begins. Now, what is the target animal 90% of the time and the bullet of choice? Then I would shop for my favorite brass brand and buy a bunch.
You possibly won't need to cut any part of the tenon if you chamber something in a slightly larger in diameter and length case. Headspace on a shoulder fit might be needed (not my area of knowledge), but the action would needed for measurement to headspace properly. If there's enough length to have for re-tenon then going saum, wsm or prc is possible. If not, going 28n, rum or stw is the way to go. Would you be using a different stock or be limited to 3.340ish length?
Sounds like you will be doing your own work? If so it is not terribly difficult and very cost effective especially if you rent a reamer.
If you are having a gunsmith do the work, then the least expensive process is to ream the chamber to a larger size.
For any setback work (cutting off some of the shank) if the existing barrel shank is shortened then the shoulder must be moved forward and the thread continued to properly fit the same action. Picking up the existing thread and continuing is a PITA but can be done. Would be easier to remove the entire shank and start over but that would move the barrel rearwards in the stock most likely making a larger gap in barrel channel.
Easiest way is to pick a larger chamber reamer that will clean up the existing 7 Rem mag chamber. Other posters have mentioned some. Having a lathe and a bunch of reamers I have done this with a 243 going to 6mm-284, 7-08 to 284 Win, 25-06 to 257 Weatherby and 300 Win mag to 300 Rum to name a few. It is the simplest approach.
I took a Rem takeoff in 7 Rem mag cut off some of the shank, turned down shank and rethreaded for a Ruger and make it a 284 Win. Same sort of thing with a Rem takeoff to fit a push feed model 70. Both of these actions use a 1" diameter x 16 TPI so a Rem shank with its larger 1 1/16 dia x 16 TPI can be turned down and threaded.
Tikka T3 barrel is also a 1" x 16 tpi but its shank is longer than a Ruger or Model 70 push feed so some has to be removed and then rechamber.
If you are having a gunsmith do the work, then the least expensive process is to ream the chamber to a larger size.
For any setback work (cutting off some of the shank) if the existing barrel shank is shortened then the shoulder must be moved forward and the thread continued to properly fit the same action. Picking up the existing thread and continuing is a PITA but can be done. Would be easier to remove the entire shank and start over but that would move the barrel rearwards in the stock most likely making a larger gap in barrel channel.
Easiest way is to pick a larger chamber reamer that will clean up the existing 7 Rem mag chamber. Other posters have mentioned some. Having a lathe and a bunch of reamers I have done this with a 243 going to 6mm-284, 7-08 to 284 Win, 25-06 to 257 Weatherby and 300 Win mag to 300 Rum to name a few. It is the simplest approach.
I took a Rem takeoff in 7 Rem mag cut off some of the shank, turned down shank and rethreaded for a Ruger and make it a 284 Win. Same sort of thing with a Rem takeoff to fit a push feed model 70. Both of these actions use a 1" diameter x 16 TPI so a Rem shank with its larger 1 1/16 dia x 16 TPI can be turned down and threaded.
Tikka T3 barrel is also a 1" x 16 tpi but its shank is longer than a Ruger or Model 70 push feed so some has to be removed and then rechamber.
Bang4theBuck
Well-Known Member
I'm surprised that someone didn't mention checking the barrel twist of the 7RM. I believe the standard twist 1:9.25 or so. This will be a determinant in what bullet you will be able to shoot. It seems to me that the sweet spot would be to find a bullet that stabilizes in that twist at around 3000 fps, and then figure out which cartridge pushed that bullet to those speeds, and it's the same case diameter as the 7RM or larger and go with that. Then look at how much you would have to.set the barrel back to get.into fresh rifling, if the case length of the cartridge you choose (28 Nosler as an example) is longer by enough to get you into fresh rifling, then there is no need to set it back.
That's how I would make that decision, if you are convinced you want to use the new barrel.
I would weigh that against the cost of a new Remage barrel from Northland Shooter Supply (~$400) before I settled for anything I wasn't going to love with the old barrel.
Good luck
That's how I would make that decision, if you are convinced you want to use the new barrel.
I would weigh that against the cost of a new Remage barrel from Northland Shooter Supply (~$400) before I settled for anything I wasn't going to love with the old barrel.
Good luck
Fishman1978
New Member
When you dial in the barrel to go from say a 243 to a 6mm-284, are you dialing in on the chamber wall or are you using a long reach indicator to reach the lands?
Or a range/indicator rod?
I have a new fluted 308 Win barrel that I want to rechamber to 300wsm and was wondering what to use to dial it in.
Thanks
Ark. Trapper
Well-Known Member
The easiest thing to do would be to shave .004-.010" off the shoulder, the back of the shank, and out of the bolt nose recess then run a 7-300 win mag, 28 Nosler or 7STW reamer in it. No muss, no fuss. Guncranks all over the world did it by the thousands with 7mm Rem Mag barrels when the 7STW hit the scene. Still do. I have a 7-300 win mag that I did that exact thing to. Yes most 7 rem mag barrels have 1-9.25" twists but since the 160-170 grain bullets outperform the heavier stuff out to 1000 yards anyway its not a handicap IMO. If your current action is a belted mag you will also need to open the feed rails if you do the 28 Nosler..
Love the STW. If you opt for the STW, be aware that some minor modifications may be needed to your stock and mag box to accommodate the added length.
