Ejection Routes Inconsistent

[Dr. Bullseye]

Do you have an H buffer now? My ejection pattern was fixed with just an H and blue spring from Sprinco. The H2 buffer was a little too much and sometimes the rifle failed to lock back on the last round.

[masterdrago]

Yes. The P516 Sig came with a mil-spec spring (right at 10" & 36 coils) and an H buffer. Today, I received the "Blue" Sprinco (11" & 33 coils) and an H2 buffer from Primary Arms. I'll have it in tomorrow but may not have time to run some ammo through it until Saturday. Since starting the thread here, and getting suggestions, I've found numerous verification at americanrifleman.org, and articles by Patrick Sweeny to use the H2 buffer and possibly a stronger spring as a possible fix to all the issues I'm seeing. Is your ejection pattern with a 10" suppressed and adjustable gas block? Mine is on the smallest setting (suppressed 1of4).

Got the H2 buffer and "Blue" Sprinco spring in and just as a quick check, ran 5 rounds of American Eagle XM193 55gr. It had a very different feel & sound - less abrupt jump. The twaanng sound was also gone, although that never really bothered me. It ejected at 3:00 and the bolt locked back after the last round. So without getting too excited, seems good. I'll get out in a week or so to put a few hundred practice rounds downrange. Will check back in after. Thanks all. Seems to me that Sig would know that folks may suppress this shorty and built the adjustable block with a series of smaller ports, put in a heavier buffer, and maybe a stronger spring. I read that 10", which mine measured last night, is about the minimum for a carbine length buffer spring.

[Dr. Bullseye]

Mine now ejects at 3:00 and I couldn't be happier. It sounds to me if your problem may be solved.

[Guntoter]

If you look at the barrel extension, right at the edge of the grooves for the locking lugs to pass, you will see peening where the bolt lug edges are slamming into the extension. You can also see where the feed ramps on the extension are slightly out of line with the receiver ramp cuts. The extension is slightly "clocked" in the receiver and either the alignment pin needs shimmed or the barrel/extension replaced. The bolt hitting the extension may be slowing down the closing, causing the issue of the bolt not closing all the way. Conversely, on opening the lugs are no doubt dragging against the extension which may be changing the opening speed giving you inconsistent ejection patterns. The heavier spring and H2 buffer will put more force behind the bolt which overcomes the friction of a misaligned extension, thereby aiding closing completely, but the issue is still there. I'm surprised Sig did not catch this but with the issues people have had with Sig pistols going back for repair it's not surprising.

[MistWolf]

...an occasional round getting chambered b4 a spent round completely clears the box so you have a spent casing facing in between the bolt and chamber.

This is a common malfunction and is caused by a weak or marginal extractor spring. Replace your extractor spring with a Colt or Sprinco M4 extractor spring. No O ring.

If, after replacing the extractor spring with correct extractor spring- let me emphasize correct extractor spring- the bolt does not close and lock, replace the action spring with a new standard spring or a Sprinco blue spring (assuming your AR is equipped with a carbine RE).

[tehpwnag3]

OP's issue has been going on for over 2.5 years, since it was new. OP needs to get it back to Sig so they can make it right. Bouncing around from forum to forum isn't the answer.

[MistWolf]

If Sig misdiagnosed a common problem the first time it went back, what makes you think they'll get it right the second time?

[tehpwnag3]

https://sigtalk.com/sig-sauer-rifles...lure-feed.html

The start of the thread is various experiences and troubleshooting tips. You can fast forward to post 25 on page 2, if you want.

Again, if OP wants to throw money at it, up to him. Even if it took a few iterations, I'd make Sig get it right even if meant that they swap out the entire upper and/or action parts of the lower. Supposedly, they have good CS and will pay for shipping both ways. I have also read that they don't care if non-stock parts have been installed. So, it sounds like the better play to me.

[MistWolf]

I'm only concerned with the problem described in this thread which I quoted in post #37. The problem I quoted in post #37 of this thread is an extraction problem caused by a weak or marginal extractor spring.

[.223Pound]

Extractor deflection is just the amount that the extractor moves when the case rim slides under the hook. It is controlled by the travel limiting pad of the extractor. It can be increased by filing down the travel limiting pad.

I measure the extractor position by using sheet metal strips filed to various widths like a feeler gauge. If the rim diameter is .473 and I measure the static extractor gap at .462 I then have a deflection of .011.

Excessive deflection combined with very high tension can cause feeding problems.