7WSM conversion

[Varmint Hunter]

I've got a full custom rifle in 7WSM. It has a 25" Bartlein 3b with an 8.5" twist. The Borden action is (I believe) a magnum face short action. Never having the option of quality brass (without converting from other WSM cartridges) has grown tiresome. What can I rechamber the barrel to that would have high quality brass available?

 

[ARlife4me]

Well all I can think of is replace the barrel in most any caliber for action length. I don't know of or have ever rebarreled any before.

 

[adam32+P]

7mm SAUM and use ADG brass.

 

[chutinlead]

7SAUM or 7SS (Sherman Short)

 

[Pdvdh]

Hard to find a 7mm cartridge with a larger case diameter and a magnum bolt face / case head diameter than your 7mm WSM, for purposes of rechambering your existing barrel. I can't think of any factory SAAMI cartridge larger in diameter than your 7mmWSM chamber.

You may have to start with a new barrel if dead set on a different cartridge for your Borden short length action with the magnum bolt face.

I located a 100ct box of Norma 270WSM casings. So I'm rechambering a 25-300RUM to a 25WSM, because the WSM case is slightly larger in diameter than even the RUM series of cartridges. But my rechamber of my existing barrel will require that the threaded tenon on my barrel be cut off, and a new threaded tenon cut, because the WSM case is so short.

 

[Varmint Hunter]

7SAUM or 7SS (Sherman Short)

I'm assuming the SAUM is too narrow but will the 7SS clean up a 7WSM chamber?

 

[chutinlead]

I'm not sure but from what I've heard, the guy at Sherman is pretty helpful and would probably know the answer to that. I'm betting you'll have to shorten your barrel no matter what, just a matter of having to set it back .100 to cleanup, or a full barrel tenon worth.

 

[ARlife4me]

I'm assuming the SAUM is too narrow but will the 7SS clean up a 7WSM chamber?

Going from a 7wsm to a 7suam is like dropping a 380 in a 9mil chamber. I'm not familiar with Sherman cases. I could be the odd duck in this pond!

 

[Rhovee]

I would cut a few threads off and do a 7/300 wsm. The wsm case is the widest of any 404 Jefferey.

 

[Varmint Hunter]

I would cut a few threads off and do a 7/300 wsm. The wsm case is the widest of any 404 Jefferey.

I should have done that when I rebarreled a few years ago. I've got the dies and tools for the 7WSM and thought that someone would be producing quality brass long before now. Maybe I'll just shoot the gun until the Bartlein is toast and rebarrel. My McMillan stock will accommodate a much heavier profile bbl and I'm becoming partial to the new(er) carbon barrels. MY Proof (6.5PRC) really shoots well.

 

[Idaho Lefty]

I would cut a few threads off and do a 7/300 wsm. The wsm case is the widest of any 404 Jefferey.

This is WHAT, I'd DO, too ^^^ in, a New York, Minute !
Just cut a couple of Threads off and re-chamber to 7mm-.270 WSM as it's easier to get .270 WSM Brass and you WILL get, BETTER, Neck / Bullet TIR, "runout" readings, by "Expanding" Necks than, by squeezing them, down,.. and possibly causing,.. "Doughnuts" !
This design is, a Superior 7mm round and is used by, the Canadians and English @ 1,000 Yard Matches !
Only the .300 WSM beats it at, 1,000 yds as, the BIGGER Higher BC, Bullet has, a bit less, Wind Drift !
The 168 gr. HVLD Berger's, would BE,.. "Smokin' !
And it's NOT, an "Expensive",.. FIX, either !
Your Rifle sounds like, a NICE one and well Worth, a couple Hundred Bucks more, to make IT,.. RIGHT !

 

[can1010]

if you have enough unthreaded shank left so that you can cut all the threads off and then rethread it will open up more options. that would allow you to do 7 SAUM.

 

[grouse]

I love the 7wsm. I understand the brass issue. So I'm also going with a 270 or 300/7mm and lm building soon. Have the reamer and gauges.
Winchester brass is not that bad and it's pretty easy to find. On a recent podcast with Ryan Avery and Ryan furman discuss the wsm case at great length. He has has great luck simply sorting Winchester brass.

 

[JAYgs8163]

I know Hornady is not ADG or Lapua but they're making some pretty darn good 7WSM brass now. Requires some prepping and annealing but seems to be pretty darn good stuff.