Ejection Routes Inconsistent

[masterdrago]

I'm seeing very inconsistent ejection routes when firing a full mag of ammo. This happens mostly using either 55gr AE XM193, 62gr AE XM855, or other low cost ammo. I sometimes get failure to seat a round (bolt not closing all the way) and will get FTF then. If I push the forward assist, it will close and then successfully fire. I've had off and on issues with this same problem since getting the Sig P516 10" which I've replaced the brace with a adjustable stock (Form 1). Sent it back to Sig early on and they ground the feed ramps which vastly improved the cycling. B4 that, new rounds out of the mag might jam going up the ramps. They would literally be bent and dented. Ammo that gives no issues is the Hornady 75gr TAP SBR which ejects at 4:00. I've tried different lubes but mostly have been using the TW25B and once even lubed the bolt lugs with a generous helping of grease (got 80% failure to lock). It's suppressed if that matters and am using on the suppressed setting but the ejection pattern is just all over the place. Has anyone tried using the Black Rifle Balm from Cherrybalmz? Can anyone give me some suggestions on this issue?

[26 Inf]

You talking about lube causes me to ask if you are lubing the gas piston or the valve itself. Generally this is a no-no for piston systems as some lubes will cause the systems to carbon up quickly.

[masterdrago]

No lube or any work on the piston or the adjustable gas block. In my most recent cleaning and re-lubing, I was careful to only lube using the instructions at https://www.cherrybalmz.com/post/how...um-reliability. Prior to that I was using a diagram at https://www.ar15.com/forums/ar-15/-/7-548967/ which had me greasing the bolt lugs and gas rings & firing pin which cherrybalms says not to do. So for a novice AR guy, it just gets confusing. And with no experience with an AR except the 500 or so rounds through this Sig 516 10" + suppressor, I'm mystified as to the variation in spread location of ejected ammo. Also 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. My son said it was something he had never seen and he shoots often.

[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?

[masterdrago]

Since I'm still very new to the AR platform, I'm trying to get all the help I can.I'm not real confident in Sig's ability to diagnose and solve the issue although that may be how it gets done. But doing that, leaves me still ignorant. I'm at a point where I want to learn something. Hence multiple forums, etc.

I did make it to the range today with just more and still disturbing finds. It is still having issues getting the bolt closed before an empty casing is cleared. Seems to be ejecting at 2:00 but may be bouncing off the deflector. Not sure. Will attempt some high speed video on next shooting. It also does not always completely chamber the live round as if the bolt just stops with the round about 3/4 in the chamber. Does not matter what ammo, magazine or when. Random but about 2 or 3 per magazine. The round can be very hard to get out and is bent and scratched badly. Several pix.....







I do plan to see what my dealer might do for me. Maybe they will take the rifle and handle the return. I was not real comfortable mailing it when it went back to Sig back in Dec. 2016, 9 months after purchase.

[georgeib]

Are you having these same issues unsuppressed too?

[masterdrago]

Are you having these same issues unsuppressed too?

It's been a long time since I've run it un-supressed but yes, intermittent jams and a few failure to close the bolt all the way. I was planning on taking it to the range on Friday but may have to delay that. I'll work through the 3 possible ways (non supressed, supressed, and gas block setting change) with the same ammo in a bit. Will try to document better.

[georgeib]

I would try a new and/or heavier action spring, and an H2 buffer. Also, I like to lightly grease my action springs and the inside of the receiver extension, as far as I can reach in. Really smooths out the action.

I also lightly grease the bolt carrier rails, and the outside of the charging handle. Manually cycle it until you feel it smoothing out.