Introducing the 7.62X40-the new .30 caliber AR solution

[rsilvers]

The 6.8 has a larger head than 5.56mm, but at least one test did not show a difference in bolt life.

7.62x39mm is even larger, and I am just not comfortable with it - especially since I made a 7.62x39mm upper and I never had a bolt last more than a few hundred rounds. True - it was a 10 inch barrel, FA, with a suppressor - but in 5.56mm that would still last at least 6000 rounds.

The way to make it larger on an AR is to do what Remington did with the 30 RAR and have a special bolt and special barrel extension.

The curve you see in AK mags is optimal for the 7.62x39mm. Any less of a curve causes buckling and binding.

[Altair]

What are the case dimensions of the 7.62x40 and capacity compared to the 300 Blackout?

It is approximately .200" longer. I trim my BLK brass to 1.355" and my 7.62x40 brass to 1.555". The 7.62x40 also has a bit of the case taper taken out when fireformed (more on this later)

What pressures are both rounds loaded to?

Both can handle the same pressures as the .223 parent brass, which IIRC is 55,000 PSI.

How deeply does the 150 gr bullet intrude into the powder space? Which 150 gr bullet is used, is it a flat base or boat tail?

You could use just about any 150gr bullet, but in the 7.62x40 and the 300 BLK you are beyond the point of diminishing returns IMO. If you do it to make major power factor for competition, that's fine, but most 150gr .308" bullets won't do much at the velocities you can get in these smaller cases. That may change as bullets designed for the 300 BLK start coming out but for now, the bread and butter for supersonics in both will be 110-125gr.

With a twist of 1:11 or 1:12, does that mean this new round intended to run bullets of 150 gr & less?

Yes. From what I've read from the original designer, Kurt, it was intended as an improvement on the 300 Whisper for supersonic use.

Has the 7.62x40 been submitted to SAAMI? The blurb states that the factory ammo will be fire-formed upon firing to give an additional grain of capacity. Where does the factory case headspace? When fire-formed, what changes? Does the fire-formed case have less body taper and/or steeper shoulder angle?

I'm not at home or I'd post a picture of an unfireformed case next to a fireformed case but in short the case taper is straighter in the 7.62x40 and the shoulder angle is different. There isn't much of a shoulder, but I like the sharper shoulder for more positive headspacing so I usually fireform my cases before loading to full potential. It may not be necessary, but I feel better about it.

What has been posted is a lot of advertising hype with very little technical data

Info will come out with time and the right questions. I've been following alot of the threads on the 7.62x40 since I've had one of the early barrels for a while now. Bill and his employees have gone above and beyond providing info and being completely up front about what the cartridge is capable of. I think they are being a bit conservative about velocities, which I'm glad to see. Nothing more frustrating than being told something will perform to a certain spec and then being disappointed when it won't do it.

I'm glad to see it going mainstream since I've been very happy with mine. I'm anxious to get my hands on an 11.3" barrel. My current barrel is in the 16" flavor.

[Altair]

hmmmmmmm... mags are not ridiculously priced, barrels are cheap, ammo price isn't bad at all considering it's proprietary. i probably won't be the guinea pig, but i'm definitely interested.

looks very promising, WC.

You wouldn't be the guinea pig. This has been around since 2008 IIRC. First discussed on Quarterbore and then on AR15.com. I've had mine for a while now and had alot of fun with it. It has some pretty impressive performance in such a small case. It, like the 300 BLK, is very efficient in short barrels due to the small shoulder and near straight wall design. I prefer my AR's with short barrels so I like this cartridge alot. As stated in my last post, I'm very excited to see 11.3" SBR barrels available. I'm just out of spare cash at the moment.

[rezin23]

Are other manufactures going to start producing this round?

[Altair]

Are other manufactures going to start producing this round?

According to Wilson it is open for others to produce. That is one of the reasons they are talking about posting the reamer print on this web site. I imagine others picking it up will depend on whether it gains enough popularity to make producing it lucrative for another company.

I certainly hope so.

[kh86]

When will the cheap target ammo be availble?

[FrostyEOD]

When will the cheap target ammo be availble?

You mean the military surplus or commie stuff?

Never.

[tommyh]

Is ammo availability going to be better than the 300aac? Prices on waht you show online seem to be inline with what you can get Rem corelokt 223 from box stores, 6.8 110gr or 115gr, so its reasonable, but if you can't get it, then its not worth purchasing the hardware. whats the word on that?

[wilsoncombatrep]

Guys,
We have loaded ammo for the 762x40WT on the shelf, and plans to continue to load it as needed. I have no word on any other company(s) that will load it in the future. You can get all you want at...

http://shopwilsoncombat.com/Wilson-C...partments/107/

If you want cheap(er) blasting/training ammo for an AR, then 5.56 is the way to go...if you want more punch out of that same AR by simply changing uppers and switching mags, now you have another option

[dan rockway]

This might be just ok for small deer. I sure wouldnt go for anything bigger than a blacktail though. Doesnt even have the power of a 30-30