7.62x40 AR platform?

darkminstrel · Mar 28, 2012

Just got done reading about this round, and it may be the one that changes my mind about picking up an AR.

7.62×40 WT Project - Soldier Systems

Anyone on the board have/shoot one of these?

coop44 · Mar 28, 2012

another "experiment" with expensive ammo. Yep, I'm gonna jump right on that band wagon!!!!

jquirit · Mar 28, 2012

Looks like another interesting design, but I do have a slight "concern" about it due to one detail: WT says they reform existing 5.56 brass up to the 7.62x40 casing. What I think that means is flaring out the neck from 0.224 to 0.308 (since the shoulders in that link seem to match up), which isn't a trivial jump. My concern would be with reliability of reformed brass after performing such a function (such as thin wall thickness around the neck.. risk of cracking/splitting).

Now, cases made specifically for the 7.62x40 chambering I wouldn't have an issue with...

mjbskwim · Mar 28, 2012

A couple guys up here had the 300blackout.They decided that for economic reasons the 7.62X39 make the most sense.As accurate as the .300 and I'll guess it will be the same for the X40

You get an AR with a way better barrel than an SKS or AK and you will have an accurate 7.62X39 rifle.
The X39 ammo is just too cheap to really buy into the new blackout and this new X40
For the savings,you can buy a few BCGs if you break one.

So unless you just have to have the newest caliber,I don't think I'll be jumping on the wagon either.

del_and_bones · Mar 29, 2012

I have a 300BLK SBR so you know who I'm rooting for.

I don't see any added benefit to 7.62x40WT over 300BLK. I can't see it getting more than a 10% added velocity bump over 300BLK and the ammo is guaranteed to be more expensive unless more companies back it like the 300BLK. Plus you can just convert a saiga in x39 and shoot circles around either one.

ETA: I agree with the statements by mjbskwim and Norm0931 (next post).

Norm0931 · Mar 29, 2012

mjbskwim said:
A couple guys up here had the 300blackout.They decided that for economic reasons the 7.62X39 make the most sense.As accurate as the .300 and I'll guess it will be the same for the X40

You get an AR with a way better barrel than an SKS or AK and you will have an accurate 7.62X39 rifle.
The X39 ammo is just too cheap to really buy into the new blackout and this new X40
For the savings,you can buy a few BCGs if you break one.

So unless you just have to have the newest caliber,I don't think I'll be jumping on the wagon either.

This is honestly the truth. The fact that X39 ammo is so available for such a low cost and modern gunsmithing can accurize the round there is really no reason to develop a replacement for it. If the military decides to switch rounds then we will see a bigger jump but, until the military leaves the 5.56 I don't see any of these cartridges really toppling the current thrones of 5.56, 7.62x39 and x51. Not to say these rounds aren't cool, they just lack economic support.

mjbskwim · Mar 29, 2012

Maybe the 7.62X39 on the AR 10 platform would work better.The complaint I have read is the BCG is kinda thin in the 5.56 AR.Not strong enough.
So if it was made on the AR10 platform only the chamber would need changed,no?
Well the mags.OK that was the other problem,the X39 mags don't feed good in the AR?

Is this thread jacking?
Sorry

DieselScout · Mar 31, 2012

del_and_bones said:
I don't see any added benefit to 7.62x40WT over 300BLK. I can't see it getting more than a 10% added velocity bump over 300BLK ....

Does anyone know the difference in case capacity? From an article I read recently, an increase of 10% case capacity gives you and increase of 2.5% in velocity, so to see a 10% difference in velocity, you'd need a difference of 40% in case capacity. I can't find any solid number on the 7.62x40WT case capacity.

Personally I think it's a useless round, another answer to a question no one asked. It's just another way for Wilson Tactical to get their name out there. I am not faulting them by any means, business is business, there just seem to be other more established calibers that do everything this one does.

mjbskwim · Mar 31, 2012

I can't find any solid number on the 7.62x40WT case capacity.

I looks like they are using the 223 cases and necking them back up to .308.So the capacity would be a couple grains different.The increased bullet volume would negate and increase in the capacity from increasing the neck,no?

DieselScout · Mar 31, 2012

mjbskwim said:
I looks like they are using the 223 cases and necking them back up to .308.So the capacity would be a couple grains different.The increased bullet volume would negate and increase in the capacity from increasing the neck,no?

I have no idea lol. WT's website says that once formed brass is fired capacity will increase by a grain, but never states the case capacity.

mjbskwim · Mar 31, 2012

darkminstrel said:
Just got done reading about this round, and it may be the one that changes my mind about picking up an AR.

7.62×40 WT Project - Soldier Systems

Anyone on the board have/shoot one of these?

As you can see, the round is based on a resized 5.56 case. This allows it to be used in a properly barreled AR-variant and the ammunition will work in a standard AR magazine but with fewer rounds per mag. In fact, the only unique requirement is a new barrel.

This says it's the 5.56 case,so the volume would be within milly units the same volume

del_and_bones · Apr 1, 2012

I took <broken link removed> , found the volume below the neck (~.133 in^3), and shoved it into wolframalpha which came up with 33.6 grains. I read that 300BLK is about 25.1 grains, so it does have about 34% more capacity.