7.62 AR-10 mild Kaboom

[sinister]

Sorry, yes, the 7.62 MWSs.

I see they also do 6.5s with 7.62-length gas tubes. They don't use 2+ inch longer gas tubes, which may not make a difference if no one tries to put a suppressor on it.

[SFree]

Surely, the manufacturers wouldn’t know that with a short-barreled, gas operated rifle in the 7.62 cartridge class that people would want them suppressed? Isn’t that the logical or a logical reason for a short-barreled system in the first place, for sound suppression? Just the concussive blast from a short-barreled large frame AR would mandate suppression…. Am I way off? I’m just learning

[Jsp10477]

Surely, the manufacturers wouldn’t know that with a short-barreled, gas operated rifle in the 7.62 cartridge class that people would want them suppressed? Isn’t that the logical or a logical reason for a short-barreled system in the first place, for sound suppression? Just the concussive blast from a short-barreled large frame AR would mandate suppression…. Am I way off? I’m just learning

Meh, it’s not an issue, with ear protection, to shoot a 16” 308.

[Exiledviking]

Oh, yeah -- SIG suppressors are REALLY good.



The good news is Pappabear went first-class with both the rifle and suppressor.

The "Iffy": the mid-length gas system didn't do you guys any favors.

For those interested, 16" Mid:



18" Rifle:

I have a 16" 7.62 with the factory bolt carrier and buffer. I do not shoot suppressed and 99% of my ammo is German surplus and some 150 gr Fusion ammo. My understanding is the primary issue above is due to the suppressor, is that correct?

Would my LMT MWS benefit from adding a BRT gas tube?

[sinister]

Necessary or required, no. The rifle will certainly function, and the brass will do its job.

If you reload, it can't hurt your brass.

[markm]

Would my LMT MWS benefit from adding a BRT gas tube?

Hard to say. You can almost get an idea on our ejection. If it's really snappy and aggressive, you might enjoy the rifle more with a little gas reduction.

[Todd.K]

Never seen one like that.

The reason the extractor is not damaged is because this was not an overpressure. Brass goes liquid at high enough pressure, it flows out under the extractor until the case fails.

This was normal pressure and the case failed because it was unsupported.

I’m not sure how. Broken firing pin perhaps.

[sinister]

The reason the extractor is not damaged is because this was not an overpressure. Brass goes liquid at high enough pressure, it flows out under the extractor until the case fails.

This was normal pressure and the case failed because it was unsupported.

I believe this shows yes, the case was unsupported because it had been partially extracted while the chamber and in-barrel pressure still obturated the case against the chamber. Mark said the neck appeared to have been blown-out and fire-formed to match the chamber shoulder.

It looks (to me) like the case gave way at or just above the extractor groove. The case walls held until the head un-corked, and backed-up gases that didn't go out the muzzle bled back into the upper and out the ejection port.

The soot stained the base of the case that wasn't in the chamber.

[georgeib]

I believe this shows yes, the case was unsupported because it had been partially extracted while the chamber and in-barrel pressure still obturated the case against the chamber. Mark said the neck appeared to have been blown-out and fire-formed to match the chamber shoulder.

It look (to me) like the case gave way just above or at the extractor groove and the case walls held fairly well until let-go and pressure was suddenly un-corked.

Agreed that at some point it was unsupported, but how can we explain that Mark fired the weapon when this occurred? I mean, the round was fully chambered. Weird.

[Todd.K]

The soot stained the base of the case that wasn't in the chamber.

Yes, the soot and the shape of the case there shows how far out of the chamber the case was.

I’m not convinced there is enough pressure after the bolt is unlocked for this much of a rupture / fire formed case.

I think the rim would be pulled off by the extractor. Because residual pressure will make the case harder to extract, and that damage would be quite a bit of pressure.