7MM WSSM, has it ever been done?

[Kenny474]

I have always liked the look of the WSSM cartridge, but I have heard the .223 and .243 are barrel burners. I have been thinking that increasing the bore to 7mm would reduce throat erosion, and still provide good performance. Any thoughts or insight from anyone? If you have experience with the WSSM line and have any info to give, I would love to hear it.

Also, how do they compare to say a 6mmBR accuracy wise?(if chambered in comparable rifles) If this is something that will have me chasing accuracy or they are just not accurate cartridges, please let me know. I have looked all over the net, and have yet to find any info on this ever being done, which could mean it's a bad idea and a waste of time. Just like a little insight before I waste any more time thinking about it.
Thanks.

 

[kemlin]

I built one from a 243 wssm reamer and then used a chuck reamer for the neck area that made for a slightly trimmed case. I shoot light bullets in it (115 grain speer hp) for p-dogs and have had great luck with it. On paper at 200 I don't keep guns unless they are under .5" with 5 shots and this one made that with no trouble. 115 grain speer hp bullets and 43 grains of H-322 IIRC. It is a kitten to shoot also.

 

[buffybuster]

A 7mm WSSM would probably be like a 7mm-08 but without the action length issues in a SA.

 

[kemlin]

With testing mine I get more velocity than out of a 7mm-08 according to the reloading guides and quickload. I was really impressed with how it did at the range the thing is a tack driver. It is a ton of work getting the brass right especially since mine is a tight neck setup but the cases anneal nicely. I used the cheap federal 223 cases for a parent and step to 243 wssm and then use a 25 caliber expander and then to 7mm. I only lost a couple of cases necking up and that was when I was using a K&M tapered expander and doing it in one shot. If you would like I can dig out my load info and share what I can find.

 

[Bigd7378]

Would like to see some loaddata. Any updates?, i have been thinking about the same project

 

[RDavies]

I have a 6.5 version which is working very well. I think as a 6.5 it is a realy well balanced cartridge, basicly equal to the other mid size 6.5s (6.5x47, 260 Rem, 6.5 Creedmore). It ends up looking like a 6BR on steroids. Same length, same 30 degree shoulder angle, just 30 percent more surface area and bullet weight.

 

[bozo699]

Darn you guy's,....I saw Kenny474's thread and thought he had returned after almost a years absents ,......no such luck I miss him on here he was a lot of fun. I don't believe he ever built the 7wssm I wanted to build the 6.5 wssm did you build your own cr500?
Wayne.

 

[RDavies]

Bozo699, I specced and bought my own reamer and barrel. Then got a gunsmith to chamber it in my switch barrel Barnard. I lucked onto a good barrel and the cartridge shoots great. So far in F class, it has shot mostly possibles with a good X count, shooting 140gn pills, just like a BR on steroids. In Australia, it is getting known as the 6.5 Gertrude, which is the nickname I gave it.

 

[lurcher]

I went a different way and bumped the shoulder on a saum down 200 thou

Case capacity full to the brim with water unfired is 62.5 grains. Got the rifle back from the gunsmith used a 7mm saum reamer and honed the bottom end of the chamber to avoid click at top of bolt lift. Pills will feed out of rem model 7 mag and can be seated to reach the lands

Don't know if I will get time to shoot it before xmas but hope so.

Hoping to get 162 amax rolling at 2850 or thereabouts out of a 24 inch tube, we shall see...

 

[Bigd7378]

Sweet project. Keep us informed, kinda what i've been wanting to do!

 

[Nomad47]

Bigd7378, I'll post here as well as at the wssmzone. The Winchester 70 blind mag max COL is 2.499".

 

[bozo699]

cr500, thanks for the info looks like you have a shooter I may build myself one this spring.

lurcher, neat wildcat you built, I like it

Bigd7378, Welcome to the forum.

Nomad47, I joined the wssmzone as it looked like a pretty good site, say's I am logged on yet I cant do anything or it sends me back to the log on or register page
Wayne.

 

[Nomad47]

Wayne, I saw that you had made a post over there. BTW, I'm CamoWildcat there. Was it after you made your post that you're having the problem?

 

[spclark]

Friend of mine has more than one 6.5 WSSM's he's been shooting for at least a year now, great accuracy out to 1,200 yards. I just bought myself a rifle chambered the same from a shooter in Michigan, not yet had a chance to shoot it.

Comparison to 6BR is apt regarding plusses for the geometry; accurate barrel life reportedly can be 2x or more than 6.5x284 depending on load. Appears to use about as much propellant as 243 / 308 cartridges, somewhat less than the 284-cased cartridges.

I signed on to WSSMZONE too a week or so back, never received a reply giving me permission to post but just checked & there's a welcome from CamoWildcat for myself & Bozo699 as of 11/29. Seems like a well-focused website but not much info - yet - on anything sized up from .243/.25 bore.

Are there any options for cases other than Winchester's? I got a bunch with the rifle I bought (thanks Renz!) which will last me thru the useful life of the barrel I have. Heard the WIN stuff is 'good enuf' & I'm certainly willing to give it a try but always keeping an eye open for something maybe a little better

7mm SAUM I know is a popular cartridge now for long range target shooting, a little more case capacity than the WSSM offers up but then sometimes getting more for less ain't such a bad thing. I'm sure somebody somewhere's working with a 7mmWSSM....

 

[mikecr]

Win should have made the WSSM only in 25 & 26cal, where it's useful.
I don't see any 28cal bullets that would make a 7WSSM a good cartridge, and it's too much capacity for 24cal. No bullets in 27cal...

 

[Nomad47]

Wayne, everything on your profile looks normal. I can ask Jim (wssmzone), the creator and admin, to take a look if you continue to have problems. Let me know, please.
BTW, Jim is a quadriplegic confined to a wheelchair yet still manages to hunt. He lives in Spokane.

 

[Nomad47]

Stephen, there are a couple guys shooting the 6.5 wssm. One of them is shooting 1000 yard competition in NE PA, Williamsport, I believe. He has some old posts. I will see if I can find them for you. If and when I find them, I will bump them so will find them as recent posts over there.
I asked the forum admin, Jim Mace, to look into why you and Wayne are having some issues over there. I personally approved both of you and I don't know why you didn't get a confirmation.

 

[Nomad47]

Stephen, its a long way to neck up, but Graf & sons sells Federal brass in 223 wssm. The only other option besides Win brass would be to form 6.5 wssm from WSM cases (lots of work, but it has been done).

Mike, IIRC, the 243 wssm case has similar capacity to the 243AI & the 6mm Remington. And I believe it is the fastest FACTORY chambering. I'm shooting 105s at 3250 MV from a 30" barrel, low ES's using 43.6 grains of 4000-MR.

 

[mikecr]

only other option besides Win brass would be to form 6.5 wssm from WSM cases (lots of work, but it has been done).

Yes, it's already been done -by Winchester. Haven't you noticed WSSM brass is ~20-25thou thick at the necks?

Mike, IIRC, the 243 wssm case has similar capacity to the 243AI & the 6mm Remington. And I believe it is the fastest FACTORY chambering.

Well, if 'fastest' is your goal, then I guess you're eeking that direction. But for most, the goals should be all about accuracy, and this is a no-starter with barrels lasting <1k rounds.
The 6.5WSSM matches the 260AI, which is about as much fun as practical in 26cal, still beating the 6.5-284 in barrel life.

If Winchester had released only 25 & 26WSSMs, they would be extremely popular cartridges today, covering both deer hunting and competitive uses. Instead, they made fools of themselves and many others IMO, with 22 & 24WSSMs -and formed from WSM cases!

But other than thickness, there is nothing bad about WSSM -Reloading- cases. They measure as consistent as any brass made today.
I wouldn't want Federal, or even Norma, or lapua in WSSM.

 

[Nomad47]

Then necks usually measure .0205". And over at the wssmzone forum we noticed the thick necks about 6 years ago.

Agreed that velocity isn't everything - I was just making a point. And barrel life suffers in all the speedy smaller calibers.

I got 1300+ rounds out of my Kreiger 27" barrel shooting 55 Vmax's at 3935 MV in a 223 wssm before the barrel went south. Not good, but not too bad considering the velocity I was running. I shot woodchucks and p-dogs with it, with a confirmed 823 yard kill. That gun is now a 243 wssm 8 twist 30" Kreiger. It has 600 rounds down the tube - 105 Amax's at 3250 fps. It has hit 1 foot square steel at 1250 yards. I will know a lot more about barrel life come next summer after I get to Ohio, but so far no throat erosion.