[Guest Post] The Wilson Combat 7.62x40mm WT

[ This guest post was written by Brian Nelson. ]

Not quite a month ago, Wilson Combat released the new 7.62×40 WT (Wilson Tactical) round. When I first read about it, I wasn’t sure I had a use for it.

But after looking closer at it, I think it has a real future with 3-gun competitors wanting to make “major” power factor, and hunters that want a little more punch, without taking a big step up in size and weight. First this disclaimer: I haven’t actually shot this new round. However I have looked at it in person, and talked with the round’s designer, Kurt Buchert.

What is it?

Essentially, it’s a .223 case necked up to take a .30 caliber bullet. Wilson’s stated goal for the round was to “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.’’ The only caliber-specific component required is the barrel. Normal AR mags will accept the new round, but they won’t reach full capacity. Wilson also offers modified Lancer L5 mags (20 and 30 rounders) that will get full capacity.

“That sounds a lot like the .300 AAC Blackout!” Yes, they are both very similar rounds. They are made essentially the same way, however a suppressor company designed the .300 BLK for use with a suppressor (meaning it is designed as a subsonic round) and it’s shorter. The 7.62×40 can also easily be handloaded to subsonic velocities. And don’t go thinking that Wilson just stole AAC’s design and tweaked it a bit. Kurt Buchert, the round’s designer, had been playing around with it as a “Wildcat” (one-off custom round) as early as 2007.


.223 brass is trimmed down to an Overall length (OAL) of 1.560”, then run through a sizing die that stretches it out another five thousandths of an inch. It also widens the case neck to make room for more powder, and allows for the use of higher-pressure propellants such as Accurate 1680 or H110. The end result is a round that will work with the .223 bolt face and magazines, takes the common (and hard-hitting) .308 bullet, and (mostly) fits into .223 mags.

Spec sheet for the new case. Here is the same sheet in a PDF file.


Hopefully…on target :-). But seriously, the new round is very versatile. I really dig that it makes “Major” power factor in 3-Gun (more on that in a bit), and it’s also a substantial round for small- to mid-sized game such as deer and hogs. The round’s designer said that it was “Wildcat performance for hunters who don’t reload”. Wilson now makes ammo for the new round and it’s priced about the same as .223 match ammo.


For those of you not familiar with 3-Gun, it’s a high-adrenaline run-with-a-gun sport with -you guessed it- 3 Guns (rifle-pistol-shotgun). Different scenarios are set up with arrays of paper, steel, and clay targets that are engaged with different guns, all on the clock.

3-Gun. Rifle (Jerry Miculek, Team S&W)
Pistol (SGT Daniel Horner, U.S. Army)
Shotgun (SGT James Gill, USMC)

There are two methods of scoring, one of which is called the ‘’power factor’’. Different zones on the paper are given different scores if they are shot with “major” or “minor” power factor (or PF) rounds. Obviously those shot with “major” power factor rounds are scored higher than those shot with “minor” rounds. Power factor is calculated by multiplying the bullet weight by the velocity, then dividing by 1000. “Major” power factor is 320 or higher, “Minor” must be above 150. So if a .223 round is pushing a 55-grain bullet at 3100 fps, that’s 55×3100/1000, or 170.5 power factor (minor). Shooters must make at least “minor’’ to be allowed to compete.

For years 3-Gunners got along just fine with the ‘’minor” PF .223 ammo, until the elite shooters of the Army Marksmanship Unit showed up at the 2009 Multi-Gun Nationals with custom AR’s built by the AMU’s own custom shop (which is truly a sight to behold). Chambered for a “Wildcat” round, the .30 Gremlin, they made Major PF, but ran on modified AR mags in normal AR receivers, with custom one-off bolts and barrels. But I’ve yet to see anyone except those with Uncle Sam building and paying for their guns and ammo using the .30 Gremlin as it’s a “wildcat”, with very few components, no reloading dies or any parts available for it.

Now consider the 7.62x40WT round. Wilson makes their ammo so that it will make major out of a 20’’ barrel, and it can be handloaded to make major out of a 16’’ barrel safely (but it will be veeeery hot). It’s based off of readily available .223 brass, easily trimmed and resized, and takes .308 bullets. It uses a .223 bolt, so it can be used with a “low-mass” carrier, which reduces recoil coming into your shoulder. In fact, the only unique component is the barrel, which is threaded to take AR-10 compensators/flash hiders, for obvious reasons (you ever try pushing a .30 cal bullet through a .22 cal hole?). Wilson offers modified Lancer L5 polymer mags, which there are magazine couplers and extensions for. Lancer mags will also work with the Arredondo Magwell; a popular accessory for 3 gunners. Unfortunately there is no way to make the new round work in a Beta C-mag (100 round drum).

A Lancer L5 48-round competition mag. Note the Arredondo magwell on the AR.
A Low-Mass bolt carrier assembly, Wilson-modified L5 mag, some 7.62×40 rounds, and a Wilson case gauge for the 7.62×40.


Say what you will about the AR platform for hunting, if you’re not opposed to using an AR then the 7.62×40 round is a fine round for it. As you can see, it’ll stop a hog or deer just fine, but it’s probably a little light for Elk. The new round hasn’t got a lot more kick to it than a .223, which makes it great for younger hunters.


As I mentioned before, the only caliber-specific components required for the new round are the barrel and magazine. Normal .223 mags will take the 7.62×40, but they won’t work at full capacity. The ribs inside the magazine designed to keep the 5.56 round stacked uniformly will hit on the thick .30 caliber bullet and push them out of alignment.

Wilson offers modified Lancer L5 magazines, which are tough, transparent polymer. To modify the mags, they stick ‘em in a CNC machine and trim the ribs down. They then laser-engrave the floorplates. The magazines will still feed .223 flawlessly, though.

The engraved floorplate.

It’s also possible to modify polymer mags at home, using a hand file, but Wilson recommends using Lancer mags as they have functioned 100% with the new round. Unfortunately they found that Magpul Pmags aren’t as reliable as the Lancers are with the new round, so they won’t be offering any modified Pmags. It’s also impossible to modify metal USGI mags for the new round as the ribs are stamped into the metal. And, as I mentioned earlier, the new round won’t work in the Beta C-mag 100-round drum.


If you can reload rifle ammo, it’s easy to reload the 7.62×40. But if you’re not set up to reload, Wilson does offer ammo at a decent price.

Handloading components and tools for the 7.62×40 are readily available as it’s based off of the .223 case and takes .308 bullets. Wilson offers pre-trimmed brass or you can trim your own on a case trimmer. It seem to me like the fastest setup would be a Dillon RT-1200 trimmer with a custom die (Dillon recommended CH4D), set up on a progressive press with a case feeder. Then trimming brass becomes no harder than pulling a lever.

As for dies, Wilson offers Hornady custom dies for 7.62×40, as well as case gauges. Load data can be found on Wilson’s website.

Build Your Own Gun

If you want to build your own AR for the new round, Wilson offers barrels complete with headspaced bolts. If you already have a bolt for .223 that you’d like to use, Pacific Tool and Gauge can make you headspace gauge for the new round. Pacific Tool also makes chamber reamers for it if you’d like to chamber your own barrel blank for the new round. They make the tooling that Wilson uses to make their guns in 7.62×40. As I’ve mentioned, the barrel is the only special part, so you can use your favorite handguard/bolt/carrier/whatever-the-heck-else-you-put-in-an-AR. Note however, that you have to use an AR-10 (.308) flash hider or comp on the 7.62×40.

One of those barrels could be 7.62×40!

Wilson also offers complete uppers chambered in 7.62×40, if you just want to bolt it on any Mil-Spec lower and be done with it. But where’s the fun in that? (Hint: shooting it!).


I for one think that it’s a very good round, and I agree with the Wilson guys that it’s the “Practical .30 cal AR solution”. I’ve been looking for a project for an unused AR lower for a while now, and I’ve settled on a 7.62×40 for both 3-gun and for hunting medium game (deer, boar, etc.). Thanks to Kurt Buchert for answering all my questions about the new round, and for giving me some of the gear to play around with.

This article was written by a Guest Author. The views contained in this article reflect that of the author and not necessarily that of The Firearm Blog or TFBTV.


  • Sian

    One almost has to compare the .300 BLK 1nd 7.62×40 to the Russian 9×39, as they’re both working from the same concept: necked up standard round and optimized for suppressed and close range use.

    Interested to see how both of these perform in gelatin and hunting tests.

  • Scott_T

    It’s one better than the 7.62×39!…?

  • snmp

    7.62X39 was mimic by .300 WHISPER => HK Royal Ordonace 7,62×37 => .300 AAC Blackout =>Wilson 7.62X40WT

    in same way than russian may be 9.3X40WT to mimic the Russian 9X39 (in fact the bullet is a 9.3)

  • Woodswalker

    Seems like between the .30 ACC and the rest..there is a LOT of mileage out of the original .30-221 (Whisper) and .30-223 (Apache) loads…but THOSE are Old…this is NEW and IMPROVED…Eh wot?

    OK so I’m being Snarky…but being an old school wildcatter and reloader…I’m finding that there isn’t much really NEW under the sun…change a few dimensions to make it UNIQUE and hang a new name and patent/copyright on it and go for it. Meh.

  • Noir

    Wouldnt projectile of 6,5mm Grendel make more sence instead of 7,62?

  • Quintin

    If you want a 308, just buy a rifle that fires the 308 cartridge. I will never understand this need to jam some “new” cartridge into the little AR frame. A decent FAL will do anything that needs doing, without special ammo that you can’t find anywhere.

  • michael

    I think this round has ‘epic fail’ all over it. It serves no real purpose, is less powerful and has less velocity than other similar wildcat rounds, and it requires too much to convert your existing rifle for the round. Also….why???? why this round when it’s not better or at least enough of a difference to warrant not getting the 6.8 or 308?????

  • Martin (M)

    I think this is a good idea (it’s growing on me), but I’m still needin’ to see the hard numbers on velocity and energy. Using the same lower for .223 and .30 with only an upper change is really smart, but I won’t be sold until I see how it compares to actual .308 ARs.

  • Michael,

    Did you even read the post? I described all the “real” purposes for the round, and it requires very little to convert your existing rifle. The only caliber-specific part is the barrel!


    Yes, a decent FAL can do whatever you need to do. And be a lot heavier than an AR. And kick a lot more than a 7.62×40. And move you in to a different division in 3-Gun.


    Maybe, I’m not really a ”wildcatter”.

  • Mike


    A FAL/G3/M1A/etc or a large frame (.308) AR are all heavier and less handy than an AR-15, fires a round with more recoil (albeit also with better ballistics and more energy).


    Actually, it requires the least effort to convert, compared the 6.8SPC or 6.5 Grendel (and their derivatives), which both require new bolts and magazines as well as a barrel/barrel extension. As far as other “similar wildcat rounds” the ballistics seem very similar to 300 Whisper and the 300 BLK.

  • andrew

    I bought one of the first 7.62×40 barrel and die sets from Kurt when he had them made…I think that was in 2008?

    All that is required to convert a standard 5.56 AR is a barrel (and, well, a 5/8×24 flash hider). Depending on your current barrel, you might need a different gas block.

    I like it for several reasons – you can use standard 5.56×45 cases and .308 diameter projectiles, which makes handloading easy. The fast twist means that long subsonic projectiles are going to be stabilized. Magazines? I just modified a few old PMags – though having ones available from Wilson sure is nice.

  • Vitor

    I still fail to see what this round does that the .300BLK doesn’t.

  • JMD

    “and it requires too much to convert your existing rifle for the round.”

    What? It requires a new barrel, and maybe a different buffer. Nothing more.

    I don’t understand the people that reject things like this immediately.

    It’s called innovation, people. This is how we get new, better things, and the reason we’re not still using stone axes. Not every new idea is an revolutionary leap. Most of them are incremental changes.

    And so what that it’s similar to existing cartridges. This one may have an edge that eventually allows it surpass the others. If competing designs never got released, we’d all be using Betamax or Laserdiscs still, just because they came out first. Sheesh…

  • Lew

    Because I first read about in on April 1’st I thought it was a joke. Apparently not.

  • I just want to clear up the belief stated in the article that the 300 BLK is made for subsonic suppressed use.

    It’s primary goal was to produce 762×39 ballistics out of an AR15 platform, with the ONLY component change being the barrel itself. The supersonic performance with bullets like the 110 VMax is fantastic.

    That said, it’s design also allows for subsonic loadings that cycle the action and function in standard 5.56 mags. This is more specific to LE/MIL use and not typically for hunting, etc. If you have, or ever might get, a silencer, subsonic is an awesome option.

    Add to this that it has been accepted by SAAMI and is a completely free and open standard and it is the way to go if you want a 30 cal AR. that is if you shoot typically no further than 400 yds or so.

    Also, as a disclaimer, 300 BLK is fully open-standard and so we (AAC) get no money or royalties from it’s sale. Currently, the big companies making ammo for it are Remington, Cor-Bon, and Hornady, with a number of smaller companies also involved. Reloading is very easy as the brass can be formed from .223 and dies are available from Forster and other companies.

    Guns and parts are available from AAC, Noveske, Delta Company, Wilson Combat, CMMG, soon, LMT, etc.

  • Jason,

    Sorry for the mixup.

    Do you think that the .300 BLK could be loaded to the same pressures as a 7.62×40 (to make Major PF from a 16” bbl)?

  • Brian, I am not sure of the pressures, but I do believe 300 BLK can be loaded to reach Major.

    I though Robert loaded up just such a beast, I will see if i can find out what the bullet and load are.

  • In case anyone was wondering- here’s a Major PF load for 300 BLK:

    Sierra 175 matchKing, A1680 Powder, 2.260 OAL, Rem brass and 7.5 powder. 16″ barrel, 1900fps, PF 332.5

  • rsilvers

    300 BLK can make major PF from a 9 inch barrel. 16 inch is no problem at all.

    I also want to clear up – the case length of the 300 AAC BLACKOUT is optimal for two reasons:

    1. Works with all bullet weights – 150 grain – no problem. 175 grain – no problem.

    2. Allows normal magazines to work. If the case were any longer, then you would need special magazines, like you do with 7.62x40mm.

  • Bob

    The most intelligent, logical Wildcat for the AR. I have a
    .308 AR style from JP. It is a big gun. It has confirmed kills to over a mile.
    The little AR in a 30 cal that way out performs a 30/30 or 30 carbine is what I
    have been looking for, a great semi auto brush gun. The loads right now are
    VERY conservative as Bill Wilson stated. I will bet a good deal that that
    7.62×40 is running on the low end of the pressure. I think a tested and
    measured 55,000 psi load might get your attention. There is no room in the
    Whisper or Black out or any other wildcats that are like this. With a Wilson
    adjustable gas block (not really needed) you can tune to your heart’s desire.
    Hot loads, supersonic loads and even subsonic it does it all. When I have
    reloaded my .223 till the necks become questionable. I cut the neck off and one
    push through the sizing die and ta da a 7.62×40 comes out. This is not new. It
    has been occurring in High Power matches for practice since the AR started to
    dominate. The old timers just dropped on their 7.62×40 upper and practiced
    trigger time at 200 yards. You can turn everything around that has been said
    and say why have a Whisper or a BCC the 7.62×40 beats them all and, it can be
    sub or supersonic and, you can use the tons of .223 brass that you have shot
    for high power. And there is a LOT more room in the case and, it feeds
    awesomely. No head issues it is a .233. Same clips I use in my .223 work just
    as well with the 7.62×40. Same bolt face everything. Take a hard look before
    you damn this cartridge. Supersonic is a great deer load.

  • Torn

    Sounds a lot like my 7mm TCU, just run thru a size die to neck up to a 7mm. makes about 2200 with a 120 bullet out of a 10″ Thompson Center. Never thought about trying it in an AR.