Ejection Routes Inconsistent

[ColtSeavers]

Sorry in advance, not reading the 7 other pages.

This happens with multiple different magazines? (Both manufacture and capacity wise)

Yesterday, with my sons' help, I got another video using my cell phone. If you look closely, the 1st shot loads the next round from the far side of the magazine. When the 2nd round is fired, the BCG comes back and picks up the next round from the near side (ejection port side). As it slides the round forward, something gets aligned wrong and the round bends and jams the action about 1/2" from closing. At that point, the round is not locked to the bolt face and I can draw it back using the charging handle without the round attached. To get the bent and jammed round out of the bore, I can either push it from the muzzle end with a cleaning rod or let the bolt fall hard and then force the round out using the charging handle.

The bent round is at https://i.imgur.com/3Hy8yHm.jpg

I took a close look at all 31 bent and damaged rounds, some are displayed at


Everyone has the bend and scratch marks located at exactly the same orientation on the unfired round. My son thinks something is wrong with the barrel. I'm thinking extreme over gassed, even on suppressed setting. When set on normal or adverse, the failure rate is higher. The only ammo that has low or no fails is Hornady 75gr TAP SBR 5.56 or Hornady 40gr V-Max .223. Both chrono at very consistent velocities and eject at 3:30-4:00. All of the fails seem to eject near 1:00 or all over the clock face and load from the ejection port side of the magazines.

[masterdrago]

Yes. The spreadsheet looking chart shows different magazines and ammunition used that fail. I have over 30 that show the same bend, scratch and abrasion on the bullet. Been going on since prior to Dec. 2016 but got worse after Sig polished the ramps and I added the suppressor in July 2017. I've been slow to keep on top of the fail due to life creating other "emergencies". Now I'm close to sending it back to Sig again but I want to learn as much as possible and assemble some facts b4 trusting the rifle to shipping. The suppressor will live on this rifle and it needs to be reliable with whatever ammo I can both practice with and use in HD situations. I polished them again today using Fritz after repeated brass found on the M4 ramps on a high sharp spot on the ejection port side (right).

[hk_shootr]

Rarely will a rifle function 100% with multiple brands/weights of ammo. Tune to one brand of ammo, then run that.
Seems as if you have too heavy of dc a buffer. It’s my belief that since you replaced the extractor and spring, you should go back to a factory weight buffer and spring.

Also, concentrate on function and reliability, don’t get caught up on ejection.

[Wake27]

Rarely will a rifle function 100% with multiple brands/weights of ammo. Tune to one brand of ammo, then run that.

What?


Sent from my iPhone using Tapatalk

[masterdrago]

Rarely will a rifle function 100% with multiple brands/weights of ammo. Tune to one brand of ammo, then run that.
Seems as if you have too heavy of dc a buffer. It’s my belief that since you replaced the extractor and spring, you should go back to a factory weight buffer and spring.

Also, concentrate on function and reliability, don’t get caught up on ejection.

The rifle came with a 3 position gas block (4 if you include the "no gas" setting). I'm fairly new to the AR platform but I thought I read that part of the reason for an adjustable gas block was to be able to shoot a variety of ammo. Several reviews of the Sig 516 mention that as a benefit. My Springfield Saint requires me to change a small screw. Four of various lengths came with that rifle. So far, I've been able to run several different brands/weights with it without changing those screws from the factory installed one. But the Sig can be changed on the fly (suppressed, normal, & adverse). All with different port sizes. So do you believe I'm asking too much for the rifle to digest both 75gr Hornady SBR as well as some form of 55 or 62gr FMJ? Or maybe low cost .223 for practice/plinking?

[georgeib]

Rarely will a rifle function 100% with multiple brands/weights of ammo.

That hasn't been my experience at all.^

So do you believe I'm asking too much for the rifle to digest both 75gr Hornady SBR as well as some form of 55 or 62gr FMJ? Or maybe low cost .223 for practice/plinking?

Not in the least.^

[masterdrago]

So here is a video I took on Aug. 1st. I ran several 10 round magazines at a high fire rate using my hot ammo (AE LC 55gr FMJ BT) without any jams. I know, not a big sample. Not sure if the gas valve of feed ramp polish did the repair. I'm going to experiment. I had installed a different gas block (for the 16" 516). The suppressed gas port is 0.001" smaller than the OEM. I also want to determine if the gun will run unsuppressed on the 0.059" setting. As I mentioned earlier, I had done some polishing on the ramps. I put a video of one of the magazine dumps at . Seems to be chambering out of the mag very well.

I'm planning to set up a spreadsheet of the next 300 rounds or so. I'm getting low on ammo, so it will be a mix of 5.56 and .223. Can anyone add any info that I should include in the spreadsheet? My list includes:

Ammo
# of rounds fired
Velocity
Fail yes/no
Suppressed or not
Buffer
Spring
Gas Port size
Date

[MistWolf]

I've taken some time to study your last two videos- one that shows the round getting jammed when feeding from the right side of the mag and the latter which shows ten rounds fired with no malfunctions.

What's interesting to note is the base of the round that jams stays low. Enough that the bolt almost over rides it. This puts the nose high entering the chamber and it looks like it catches on something. The timing of the BCG and the round as it's stripped from the mag looks off, like the carrier is too slow and losing momentum as it contacts the base of the case.

In the latter video, you can see that the bases of each and every round pops up higher sooner and the feed path into the chamber is much straighter. Timing looks more coordinated.

Whatever is causing the base of the case to stay low and the nose to go high is the source of your malfunction.

[masterdrago]

I finally broke down and sent the full history and rifle to Sig on the 18th. Got it back just now with paperwork showing what was done. Again, Sig polished the feed ramps but replaced no parts. I've never seen bolt lugs this wet except for the one time I followed Sig owners manual and did mine like that. Made a cruddy mess of tacky carbonized goo. So instead I've been keeping the lugs dry like mentioned at https://www.cherrybalmz.com/post/how...um-reliability. See images. I'll get to hit it hard in a few days to check out.

[georgeib]

Can't wait to see if it works for you. Hope so.