7mm WSSM as hunting alternative to 6.5 Grendel/6.8SPC

[Boom Stick]

I'm assembling an AR15 right now for hunting purposes only. I'll be using barnes bullets exclusively and reloading everything by hand. I had been debating the issue between a 6.8spc and the grendel, but I've recently found another alternative that has been projected into the forefront. Mike over at Dedicated Technologies makes custom built WSSM uppers in a variety of calibers. One of them just so happens to be the 7mm WSSM. Since I was looking at getting performance as close to the 7mm 08 as I could when I began my journey down the ar15 road, I think that the 7mm WSSM would be a pretty good alternative. I think the fact that it would be a heavier 7mm bullet would help aleviate the problem of wearing out the barrel that other WSSM cartridges face. And since I'm not yet convinced of the longevity of either the 6.5 Grendel or the 6.8SPC round I'm not sure there's much of a downside to going the wildcat route (from an ammunition availibility perspective.) Also I wouldn't need the high capacity magazines as this would be for hunting only (who goes hunting for deer with a full 26 round magazine anyway?) But ultimately, I just wanted to see what you all thought of this idea.

Also, I've got very little interest in going the AR10 route due to the increase weight/lack of accessories. Plus I already have an AR15 lower.

 

[claytonfaulkner]

I wouldn't need the high capacity magazines as this would be for hunting only

youll regret not having a high capacity magazines when the zombies take over

 

[Zipperhead]

You've posted this exact same question on the Grendel forum
[http://www.65grendel.com/forum/showthread.php?t=
and AR15.com
http://www.ar15.com/forums/topic.html?b=3&f=118&t=400197

Why here, too?

Zip

 

[rbernie]

Probably looking for people that live here and not there - no harm in that.

I would be concerned with the bolt face. I can find no commercial spec for a 7mm WSSM (only 7mm WSM and 223/243 WSSM) and the bolt face on those cartridges would seem to be too large (.535" ) for reliable use in an AR15. I know of folk who claim to use them in ARs, but I would really like to see how much bolt face is left. Chances are, the bolt (one of the weakest areas of the AR design, relatively speaking - last I looked, the Army had a 5K round life limit for them) will have a very accelerated lifespan due to the stresses of the larger bolt face.

 

[Boom Stick]

Well being the forum police/detective that you seem to be I figured you'd already know that. Not many people responded to the other threads so I decided to maximize my chances at responses. Also I respect opinions of people on multiple forums so I decided to inquire on each one. Good enough of an answer?

 

[rangerruck]

who cars where he has posted, I would do the same thing, to get as many freaks to answer as possible. So chill.
I like the idea, but I do not know enough about the wssm cases, i think they bring a few questions; I thought these were even hotter than wsm cases.
how hard would they be to feed from a semi? seems like that could be a real problem. Also, wouldn't this brass be very expensive? what kind of heat / pressure do they have, as compared to a wsm case? If you are going to handload, what about a 300wsm case, necked down to 7mm? I have heard some stunning power/long range accuracy with this setup?
I would say this, that if the wssm case feeds and ejects reliably, and has less heat, than a 300wsm, or regular 7mm case, then I would go for it, that is, if cost for brass isn't a killer.

 

[rangerruck]

You know what? I just completely changed my mind, after reading the informed post of bolt size again. I would go with the grendel round, which for a wildcat, and using a larger diameter bullet, comes as close to using all ar parts from the 223 as possible. simply make yourself 2 or 3 diff loads for it, such as , a 140 or 160 grainer softpoint, if hunting. This has been the load for the hunting 6.5 swede round for about 120 years now, and they have killed more moose over in europe with this round, than we can ever hope to. Plus it is mild mannered, because of it's great b.c., it does not have to be hot loaded.
Yep, do a grendel...

 

[Boom Stick]

Well to my knowledge the 7mm WSSM that Dtech makes is just a necked up 25 WSSM and uses the 25 bolt specifically desinged to withstand the additional pressures. Mike at Dtech said it wasn't the same as the traditional AR15 Bolt which is why it required a different bolt carrier group and a different upper receiver... However, my experience with any specific ar15 WSSM upper is nil.

And btw Zipperhead... I hope you aren't a member of 6.8forums/thefiringline/m4carbines.net or even www.pandasquarterlyforum.org... because if you are you might be really tired of seeing this thread by the end of the day.

 

[Dr. Tad Hussein Winslow]

Well, the 6.5 grendel will certainly outlast the 7mm WSSM, IMO, which is a marginal round.
Ditto for 6.8 SPC. But I say go for it; it's not a bad idea at all. Personally I'd go for the .25 WSSM or 6.5 grendel myself, because it's more suitable to the hunting I would do. But if you want an Alaska-capable gun in an AR15, then wait for the .30 RAR to come out, or this 7mm WSSM project would fit the bill, too.

 

[Bigfoot]

The bolt, carrier and extension are designed and built by Olympia. D-TECH does real good work using them. His barrels are a bit heavy so it's not going to be any lighter than a BAR Shortrack but if you prefer the AR platform then go for it.

The limited magazine capacity does leave a niche open for a double-stack cartridge for hogs and SD. I'm thinking possibly the 6.5 Grendel necked up to 358?

 

[R.W.Dale]

I really Like the idea of these wssm based cartridges. These rounds bring the AR15 up into the company of full power bolt guns in terms of game taking ability at range.

That 7mm would likely be the the best all round balanced of all the wssm wildcat cartridges, although I must say that I find the .358 intriguing

 

[Boom Stick]

Premium Sauces,

Define "outlast" for me if you would. Do you mean wouldn't wear out as fast or do you mean the round itself. The round is a wildcat so I assume you are talking about barrel life.

Also, what kind of hunting do you do? The ballistics and energy of the 7mm WSSM should exceed that of the grendel or the 25 WSSM in a more versatile package so I'm confused why you say those would be a better fit for you.

 

[rbernie]

Does anyone have pics of the boltface and/or barrel extension for this conversion? I wanna see how they fit a case that's a quarter inch larger in diameter into the same size hole....

 

[R.W.Dale]

there's pics of the bolt on http://www.dtechsuperstore.com/WSSM page.htm

 

[Marcus L.]

The 7mm would definately be more powerful, but I wonder how durable the bolt will be. In ARs 6.8 SPC, 6.5 Grendel, and 7.62x39 bolts are not as durable as 5.56 bolts due to the expanded dimensions of the case. The AR was not designed for cases of that size and as you increase in case diameter and cartridge power the durability of the bolt and bolt assembly gets worse. The 6.8 SPC and 6.5 Grendel are already pushing the engineering limits of the AR platform as it is.......this cartridge pushes it much more.

If you intend to ever shoot this rifle to any great extent, I wouldn't go beyond the 6.8 SPC or 6.5 Grendel.

 

[Boom Stick]

Well I honestly don't see myself ever putting too much more than 1,000 rounds downrange with this badboy... Since it would handloaded exclusively ,and I already have a 223 upper to go onto my lower as well as a 22 conversion kit, then I think I'll get plenty of trigger time with the same lower.

 

[Bigfoot]

That WSSM case is the same length as the 6.8 so I'd guess that most of the higher BC 7mm bullets will have ogives that are to long to work in an AR mag. Might be a good idea to ask DTECH about this.

 

[Boom Stick]

That was actually one of my thoughts initially. But depending on how far back the bullet is seated, I should be able to utilize 120 to 140 grain triple shocks and also 120 grain tipped triple shocks. Of course, this is all just theoretical and I do plan on talking with Mike extensively about it.

 

[Zipperhead]

And btw Zipperhead... I hope you aren't a member of 6.8forums/thefiringline/m4carbines.net or even www.pandasquarterlyforum.org... because if you are you might be really tired of seeing this thread by the end of the day.

Nope. [My we are testy tonight, aren't we! ] Only a member here. Long-time lurker & short-time member. JFYI, Never seen a 7mm wssm discussed here before so went searching for info on it as it must be a W/C & thought the dim's, loading and other info would be interesting, then found your other inquiries. If I were going to go W/C in a wssm case, I might consider a .264 bore. But that's me. (Kind of curious what a .30 wssm might do though, considering the case capacity is close to .308 win.)

FWIW, I have 2 - .243 wssm's (both bolties) and have had some feeding problems with one. Those short, stubby cartridges can be fussy feeders. Not too sure what their expected feeding performance would be for a semi. Also, IIRC, the original purpose of the wssm was to shorten the action to maximize quick handling qualities while reducing weight. Not sure what would be gained in the AR platform.

In my experience, factory .243 wssm is loaded very, very hot. Rumor has it that the wssm's are throat eaters. Might not be quite so bad with a bigger hole in the barrel, tho. When reloaded hot, a total 3 to 4 firings is about all you get before the primer pockets go. New brass is getting less common than it was a couple years ago, but is still available. In a pinch, I guess a guy could form them from .300 WSM, which looks like it will be around for a while.

I hope this helps.

Zip

 

[rangerruck]

it sounds like if this is to be kept as a hunting rifle, then I am liking it more. I think a 140 grain , ogive withstanding, would be possible without seating too deep at all.

 

[Boom Stick]

Yeah ranger, DEFINITELY purely for hunting. I have no illusions of storming a beach or anything (unless there are 170 class bucks on said beach)

 

[Dr. Tad Hussein Winslow]

Hi boomstick:

Define "outlast" for me if you would. Do you mean wouldn't wear out as fast or do you mean the round itself. The round is a wildcat so I assume you are talking about barrel life.

No I'm talking about populartiy/longetivity of the round. The grendel is popular enough that Wolf is making bulk ammo for it - that's saying something. The WSSMs in general are hurting, it seems to me, and in particular the 7mm one - you just don't hear much about it (quite unlike the 7 WSM). So I'd guess that in 20 years, the chances of the grendel being popular and available are much higher than the 7 WSSM.

Also, what kind of hunting do you do? The ballistics and energy of the 7mm WSSM should exceed that of the grendel or the 25 WSSM in a more versatile package so I'm confused why you say those would be a better fit for you.

Right, exactly, the .25 WSSM or .243 WSSM will kill the whitetail deer I hunt most very very well, so why sacrifice trajectory and add recoil? The smaller rounds will shoot flatter. If you want something versatile enough to also kill moose or such, then the 7 or .30 would make more sense.

 

[Bigfoot]

That 7mm would likely be the the best all round balanced of all the wssm wildcat cartridges, although I must say that I find the .358 intriguing

LOL, Krochus I posted that blurb about the 35 Grendel because I was joking with Boom Stick. The problem is it went right over his head because I misstook Boom Stick for a fella named Boomstick who is one of those working on that 35 Gremlin (Grendel). The smith devolping the Gremlin has surpassed 35 Rem velocities with the earliest loads, and it can use pointed bullets. If you want to follow the progress here's a link. http://www.65grendel.com/forum/showthread.php?t=4216&page=1

Boom Stick, I've considered the same WSSM AR route a few times but all that trouble working with that thick WSSM brass, the costs, the weight, performance, etc just never seemed worth it to me. The completed AR with a lightweight 22" barrel will weigh right around 7 3/4 lb. Before you plunk down that cash you might look at the BAR in 7mmWSM (not WSSM) that weighs 7 1/3 lb with it's better performance and factory ammo. Or the .308 version at 6 lb 10 oz. http://www.browning.com/products/catalog/firearms/detail.asp?value=002B&cat_id=031&type_id=219

Good luck with it, come back and show us some pics.

 

[R.W.Dale]

LOL, Krochus I posted that blurb about the 35 Grendel because I was joking with Boom Stick. The problem is it went right over his head because I misstook Boom Stick for a fella named Boomstick who is one of those working on that 35 Gremlin (Grendel). The smith devolping the Gremlin has surpassed 35 Rem velocities with the earliest loads, and it can use pointed bullets. If you want to follow the progress here's a link. http://www.65grendel.com/forum/showt...?t=4216&page=1

what in the world are you talkin about?

I'm talking about the 358WSSM wildcat from the same manufacturer as the 7mm. Not some oddball rehash of 9x39 russian

 

[rangerruck]

I think I am really seeing it now, a 25 wssm case, necked up, to take a slightly bigger diameter bullet. wow! I am really starting to like this scenario, should be a bit faster than a grendel, but should still be mild pressured, because of the larger diameter bullet. this could really be a great combo.