7.62x40 WT

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7.62x40 WT

Postby JoeH on Fri Apr 01, 2011 9:44 pm

Project Goal

Develop an inherently accurate and low recoil cartridge in the immensely popular .30 caliber that has more terminal effectiveness than the 5.56 while utilizing as many standard AR platform 5.56/.223 components as possible.

Cartridge Application

Designed for tactical/defense applications as well as hunting for medium sized game such as deer and feral hogs. The 7.62x40 WT (Wilson Tactical) has very useful tactical applications with soft point and hollow point bullets providing reliable terminal performance on soft tissue while the Barnes TTSX will easily penetrate tough barriers. For hunting the 7.62x40 WT vastly out performs the 5.56 and is on par with the 6.8SPC at ranges out to 175-200 yards. The VERY mild recoil of the 7.62x40 WT also makes it ideal for female and younger shooters as well as anyone that’s recoil sensitive.

Cartridge Specifics

The 7.62x40 WT is based on the inexpensive and readily available 5.56x45 Nato cartridge case. The 5.56 case is shortened to 1.560” and then re-sized (single operation) in a standard 7.62x40 WT sizing die which results in a formed 7.62x40 WT case with a finished overall case length of 1.565”. The cartridge is designed for 110-150gr .308” diameter bullets loaded to supersonic velocities, but if chambered in a 1-8 twist barrel is also suitable for heavy bullet subsonic use also.

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Re: 7.62x40 WT

Postby JoeH on Fri Apr 01, 2011 9:45 pm

This looks promising for the handloader. But why not just go with the 6.8SPC?
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Re: 7.62x40 WT

Postby 1911fan on Fri Apr 01, 2011 11:30 pm

Probably because it uses a 223 bolt face.
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Re: 7.62x40 WT

Postby BC98 on Fri Apr 01, 2011 11:53 pm

I'm definitely considering this cartridge for an SBR build. I am working on my own 6.8 based wildcat in a .223 cartridge and was also considering working on my own 7.62 version later on but this takes the guesswork out of it for me. I've got enough projects going right now and could use the simplicity.
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Re: 7.62x40 WT

Postby rugersol on Sat Apr 02, 2011 6:52 am

This sorta thing seems to be a popular topic ...

Personally, I have a hard time justifying a .308 AR ... it's doubtful I'd hunt with it ... particularly if it's much over 7 lbs. I could try to justify it for 3-Gun Heavy Metal (shooting a single-stack .45 and a 12ga pump is a lotta the appeal, here ... the rifle's simply a means to an end).

A .223-length .30 that can hit 320pf (presuming the powers that be, don't specify a COL min. 'er something), would cut down on the weight, and I'd be looking at merely a new upper ... vs. a whole new rifle.

Ideally, I'd like the option of buying factory ammo. I'm set-up to reload about 30 different calibers ... and only have time fer about 1/4 of them. And I don't believe I'd shoot a lotta 3-gun, anyhow ... jest fer fun.

At that, .300 Blackout looks interesting ... that one guy says ya can reload fer 320pf ... Remington's making factory ammo, but it's well below 320pf. No clue if they'll offer anything 'tween 123gr and 220gr.

But, I also got a few 6.8 mags ... so I'm also lookin' at the .30 HRT. Looks like 2,350fps fer 150gr from a 20in bbl.

Someone said Heavy Metal limits mag capacity to 20rd ... so droppin' to 25rd from 30rd is no big deal, with the 6.8 mags.

Only other thing'd be the longevity of 6.8 brass. Really kind of a shame Remington didn't do this, instead of .30 AR, and now putting money behind the .300 Blackout.
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Re: 7.62x40 WT

Postby Vlad on Sat Apr 02, 2011 8:18 am

I have a 330/221 WTF (300 fireball, 3oo whisper, 300 blackout...) in an AR platform with a 12.5 barrel. I have only played with 125 gr ballistic tips. I am getting 2175 ft/sec and the effects that I saw on the deer that I harvested this last fall gives me a high amount of confidence to use the round next year. The upside is that it uses standard 223 mags and bolt. Really the only change is the barrel. if you check out http://www.quarterbore.net, it has a whole forum dedicated to the round.
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Re: 7.62x40 WT

Postby BC98 on Sat Apr 02, 2011 3:45 pm

Wilson is offering factory loaded ammo, new brass, and once-fired brass.
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Re: 7.62x40 WT

Postby Norsesmithy on Sat Apr 02, 2011 7:27 pm

Remington is making a strong push with its .300 AAC Blackout round, I see that this round offers a bit more spunk, but part of me wonders if AAC Blackout couldn't be massaged to make up the difference.

Because I think that it's very likely that only one of these .30 caliber AR rounds is likely to survive commercially, and I don't know if the WT can survive the twin blow of needing modified mag followers to be loaded to full capacity and the head start that Blackout seems to have.

I mean, I've already read recipes for making the Heavy Metal class power factor with Blackout with 150 grain bullets, and that's right there with the 150 grain data for the 7.62x40mm
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Re: 7.62x40 WT

Postby BC98 on Sun Apr 03, 2011 12:02 am

The big difference between this round and the the Blackout is that the Blackout is SAAMI approved and other companies will follow on in selling ammunition in the caliber. For now, the 7.62x40 is not so only WC will be selling the ammo.

With respect about massaging the Blackout to equal performance, its case is 5mm shorter and thus will have a lower powder capacity. It would be extremely difficult to make up for that with the same bullet/powder combination. In addition, I believe that the chamber dimensions of the x40 fireform the case slightly larger and increases the powder capacity even further (approx 1gr). Wilson Combat lists an increase of 125 fps (with an additional 25 to 50 possible after the initial fireforming) over the Blackout with the same 125gr bullet. That's pretty significant.

The magazines need to be modified (portion of the front ribs removed) to allow the rounds to stack and feed properly. They can be purchased from WC or you can modify your own mags with a file, Dremel, etc. I don't believe that capacity is affected. I typically only load 28 rounds in a 30 round mag so I'm not sure that's a big deal for me.

The main reason I'm considering the x40 is the velocity advantage over the Blackout. MN doesn't allow suppressors so the subsonic performance of the Blackout is not advantageous to me. I already reload so the availability of ammo from many makers doesn't matter, either. I already load for .308 and it would be nice to be able to use the same bullets (110gr up to 150gr) for both. The powders that seem to do well in the WC cartridge will also work well in my own wildcat.

It is really intrigueing to see all of the interest in .223 based wildcat rounds now.
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Re: 7.62x40 WT

Postby rsilvers on Sun Apr 03, 2011 12:54 pm

Hello. First, I am project lead on the BLACKOUT, so consider I am biased.

The 125 grain velocity Wilson states for the 300 AAC BLACKOUT at 2275 is probably what we will load 125 grain ammo to. It is a nice conservative number that I feel comfortable we can always make and stay within SAAMI specs of 55,000 psi. Can hand-loaders get more if they want to push it to 60,000 psi against SAAMI specs? Sure.

Note that the BLACKOUT has a longer throat, like 6.8 SPC-II does compared to 6.8, or 5.56mm NATO compared to 223, so the difference is less than some might think. There may be a 125 fps difference, but it may also be about 60 fps - at equal pressure. I am just not sure, as to properly compare them one would have to take a 300 AAC BLACKOUT SAAMI pressure test barrel, load ammo to 55,000 psi, test it, and then re-ream the same barrel to 7.62x40, and then load that to 55,000 psi, and then test that.

I can say this - I am certain that 300 AAC BLACKOUT will do 2450 fps with a 110 grain bullet from a 16 inch barrel while at or below 55,000 psi. That we have tested. I have also pushed it to 2600 fps in a 20 inch barrel, but it was probably over SAAMI pressure limits and so I can't recommend that.

Remington has five more loads under development for release this year, and AAC will be distributing ammo from another company soon. I know of about 25 loads for 300 AAC BLACKOUT that will come out this year. Also some very large gun companies are working on products.

Choosing is like picking BluRay vs HD-DVD. I am going to bet on 300 BLK due to over 40 companies already supporting it, and it being more versatile by accepting a wide range of bullet weights. Also people in CA and certain other states cannot get new mags, and the military wants subsonic capability. The military will help make 300 BLK popular, and people will want the same thing they use. Also getting the last drop of power is not everyone's goal, else 10mm would be more popular than 40 S&W.
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