Overgassing?

[Grimm]

Alright guys, had a chance Sunday to go shoot it again. Shot the F&S ammo and some of the white box Federal. I actually wasn't seeing the same damage to the FS ammo as before. Had more prominent extraction marks than the Federal, but it wasn't bent or torn. Ejection seemed to be going from 2 o' clock to about 3:30 which tells me it's a bit overgassed.

I contacted Faxon and like all of you already said, heavier buffer or adjustable gas block. Mark at Faxon recommended an H3 buffer as a more economical option, but would I be better off just going gas block? Seems like the buffer is masking the problem and block would be fixing the problem.

Am I right or are there instances where the buffer is a better solution?

Brand recommendations for either one?

 

[Tomahawk67]

Buffer is the easy fix , but it will still be overgassed. If you can put an adjustable gas block on that will negate the need for the buffer change.

 

[HB of CJ]

Are you shooting factory .308 ammo ... OR ... factory military 7.62x51 ammo? Or are you shooting hot reloads sized through a .308 set of dies? Have you determined the correct gas port diameter for your Frankenstein mid length 7.62x51 barrel? Have you slugged or cast your chamber and miked it? Have you checked the head space? All easy to determine. All easy to find out.

I suspect but can not prove that you have a combination of non compatible parts exasperated by running the wrong ammo.

Respectfully.

hundreds of AR15 builds but not one AR19.

 

[Grimm]

Buffer is the easy fix , but it will still be overgassed. If you can put an adjustable gas block on that will negate the need for the buffer change.

That's what I was thinking. It'd be nice if I knew what tube/buffer it had in it.. I don't know whether it was a complete that Aero assembled with their parts or some other company. It having and SAA buffer makes me scratch my head. The joys of buying competes I guess.. I also noticed the area where the tube screws into the receiver is getting damaged on the threads either from the upper closing on it, or the bcg coming back and hitting it. It's good times

 

[Tomahawk67]

The rifle should work with any commercial ammo that is the same caliber, from subs to supers. Don't shoot ammo of unknown origin. What good does knowing what size your gas port is if it is too big as most ar10 barrels are. Headspace doesn't cause overgassing

That's what I was thinking. It'd be nice if I knew what tube/buffer it had in it.. I don't know whether it was a complete that Aero assembled with their parts or some other company. It having and SAA buffer makes me scratch my head. The joys of buying competes I guess.. I also noticed the area where the tube screws into the receiver is getting damaged on the threads either from the upper closing on it, or the bcg coming back and hitting it. It's good times

If your carrier is hitting the back of the reciever or buffer tube you have the wrong length buffer most likely ar15 length. You need the appropriate length buffer and spring before you can diagnose the gas situation.

 

[Grimm]

The rifle should work with any commercial ammo that is the same caliber, from subs to supers. Don't shoot ammo of unknown origin. What good does knowing what size your gas port is if it is too big as most ar10 barrels are. Headspace doesn't cause overgassing

If your carrier is hitting the back of the reciever or buffer tube you have the wrong length buffer most likely ar15 length. You need the appropriate length buffer and spring before you can diagnose the gas situation.

I'll look into this further then. I just noticed it last night when I broke it apart to wipe it down and saw some shiny. I figured by buying a complete lower, it would eliminate this along with pairing it with a barrel manufacturer known to work on this upper/lower combo. I guess that's the nature of the beast!Thanks for your help, Tomahawk

 

[DirectDrive]

I can't figure out if you bought a complete AR308 lower from Aero or if you bought an AR15 buttstock system from SAA ?
If it was the former, you should have the right stuff.
The latter, not so much.

 

[Grimm]

I can't figure out if you bought a complete AR308 lower from Aero or if you bought an AR15 buttstock system from SAA ?
If it was the former, you should have the right stuff.
The latter, not so much.

I bought the lower from Oregon Rifleworks in Tigard. I went there to buy a PPQ and left with that instead I emailed Aero asking what the deal is with it and if that doesn't get me anywhere, Ill call ORW. Aero sells a complete, but with a different stock and I doubt they'd use an SAA buffer. SAA sells completes with my stock, but says they're assembled by Aero..

 

[Tomahawk67]

I'll look into this further then. I just noticed it last night when I broke it apart to wipe it down and saw some shiny. I figured by buying a complete lower, it would eliminate this along with pairing it with a barrel manufacturer known to work on this upper/lower combo. I guess that's the nature of the beast!Thanks for your help, Tomahawk

The buffer tube is specific to ar10 and is about 3/4 " longer than ar15 also. To find out your buffer weight just weigh it.

 

[Grimm]

Ill measure it tonight.. Ill go buy a scale.

Just realized I dont even own a human scale let alone a small one.

 

[DirectDrive]

I bought the lower from Oregon Rifleworks in Tigard. I went there to buy a PPQ and left with that instead I emailed Aero asking what the deal is with it and if that doesn't get me anywhere, Ill call ORW. Aero sells a complete, but with a different stock and I doubt they'd use an SAA buffer. SAA sells completes with my stock, but says they're assembled by Aero..

Yep, you have to verify what you have.

"Ssa buffer carbine kit"
That's the scary part....hopefully they didn't sell you an AR15 standard buffer and spring.
Aero (if they care) should be asking you the following :
1) Length of tube
2) Length of spring
3) Weight and length of buffer (it could be marked)

 

[Grimm]

Says 308 on the buffer at least. You can see that damage I was talking about on the tube.. IllI take it apart and measure stuff. Still no scale.

 

[Tomahawk67]

Your buffer is most likely

Says 308 on the buffer at least. You can see that damage I was talking about on the tube.. IllI take it apart and measure stuff. Still no scale.

View attachment 428165

Your buffer is for dpms style 308 which is ar15 length tube and short buffer, while your tube is AR10 length which is 3/4" longer. You just need the appropriate buffer for your length buffer tube.

 

[Tomahawk67]

 

[DirectDrive]

Says 308 on the buffer at least. You can see that damage I was talking about on the tube.. IllI take it apart and measure stuff. Still no scale.

View attachment 428165

Should be a legit AR308 buffer if they went to the trouble of marking it.
Those marks look like they are from the "fat" section of your carrier....there are probably marks on it as well.
If it's rubbing like that, then you can probably feel the grinding when you work the charging handle ?

 

[DirectDrive]

Your buffer is most likely

Your buffer is for dpms style 308 which is ar15 length tube and short buffer, while your tube is AR10 length which is 3/4" longer. You just need the appropriate buffer for your length buffer tube.

Bingo
I think Tomahawk has it dialed in

 

[Tomahawk67]

 

[Grimm]

Upon further inspection, I think my spring may be the issue.. Its 10.5 inches with 25 coils which is shorter than any dpms style 308 spring I can find and has fewer coils. That'd cause the carrier to crash into the front of the extension. I measured the buffer and tube as well, those look fine. 7" on the tube and 2.5" on the buffer. That spring has me scratching my head though. I might order an orange spring from sprinco and see what that does?

 

[campwilde]

You should try the flatwire springs, much better IMO.

 

[Grimm]

You should try the flatwire springs, much better IMO.

Which do you recommend? I was seeing that you can do an armalite tube/spring with the h3 ar15 buffer on these and it's supposed to work really well. I'm wondering if that'd be a better route to go. Anyone here done that on one of these?