When shooting the 716i suppressed the action fails to full cycle. The spent casing will eject, but the bolt will not fully close when chambering a round. I have to drop the mag, slide a round into the chamber, and then drop the bolt. Doing this process the bolt slams home just fine.



The gun has less than 500 rounds through it and the can is new. With the can attached it would fail ~30% of the time.

Is this a magazine issue? Do I need a beefier spring? Bad suppressor?

Not many resources online have spoken to this issue...

https://www.ar15.com/forums/AR-15/Troubleshooting/66/

In before the Sig 716i fans / defense brigade come to defend their favorite rifle.

I had FOUR 716i that all had or developed issues including what you are describing.  

I will not be back to this thread as an Egyptian God will likely be by soon to tell you how awesome the design is (I.e. you’re a liar and don’t even own one … after you prove him wrong he’ll resort to attacking your other gun choices).

Good luck.

Buy a LMT.

Am I understanding this correctly:

Rifle cycles and ejects the spent casing
Bolt does not pickup a fresh round from the magazine and closes on empty chamber
You cannot charge the rifle with the charging handle and have to drop a fresh round in the chamber
This only occurs with the a suppressor; no issues with feeding from the magazine without the can

If that is correct I'd start with the magazine. If you're not using an M3 PMAG start there. It's a little odd that it would not feed from the magazine when charging the rifle after this failure occurs. I believe you could safely assume the can is not the issue itself.

For what it's worth I have a 716i that I run with a Sandman S. I did install an H3 buffer, however I'm not sure it's needed as the rifle length gas system in the 716i is not terribly gassy and the Sandman is not a high back pressure can at all. Otherwise my rifle is stock and has been flawless. I hunt with it.

@goloud

Any thoughts on how to solve the problem @saltiefork is having?

Did you shoot your 716I with a Nomad?

@GaryT1776

If you wake up and run into one bad 716i, you met a rifle with a problem. If you wake up and run into multiple bad 716is, you might be the problem.

I kid, I kid.

Yes, I’m pretty sure I have. If it’s not a magazine issue, I assume it’s a gas issue.

Can you try a different can?

The Nomad isn’t a high back pressure suppressor. So i doubt the bolt is moving too fast.

What ammo and grain?

I gave shot mine with a Sandman S and no issues. I have alot less rounds thru mine tho...

I can try a different can in 13 months :)

Magazine is a M3 Pmag. All parts are stock.

Sig .308 ammo - the decent quality stuff. Should I try hotter ammo?

The description you posted above is correct. The mag is the stock M3 that came in the box. Regarding the can, is there an attachment I can get to increase the back pressure?

Since it only happens with the can, most likely the bolt is outrunning the mag. Since the mag is new you can rule out a weak mag spring. I’d try a heavier buffer and/or stiffer spring.

@GLD1980

We have to have fun with it !

Try weaker ammo. Suppressors (even lower back pressure) increase dwell. If weaker ammo functions you know that can has over-gassed the functioning.

I suspect this. Sometimes bolt velocity is fast enough that this can look like short stroking.

@GaryT1776

I agree!

You jest, but you speak truth.

My gun luck is remarkable in how remarkably awful it is.  You wouldn't believe if I told you.

I'm not even going to discuss the preban Colt green label 6600 I ordered over the weekend. I went to pick it up yesterday and the dealer shipped a Colt blue label CR6724 (that 24" stainless barrel monstrosity).  When I called the dealer actually said "whats the difference ... it IS a C O L T (his emphasis)".  Cool.  Rifle sent back. Credit card dispute initiated.  My gun luck is ... Legen...oh never mind.