I'm shooting Federal, PMC and American Eagle, both 223 and 556.
Getting failure to feeds on almost every magazine. Usually the last 2 or 3 rounds.
List of Problems:
1. Failure to feed.
2. Failure to lock open on last round.
3. Safety will not go in to safe mode.
4. Inserting magazine causes locked open charging handle to ride forward.
5. Round cannot be stripped from magazine when cycles or manually using charging handle.
Tried 4 different mags, 3 different brands, including the SigMag it came with.
Did it go into safety when you received the rifle from the factory? Double check your trigger assembly to ensure safety works by disassembling and reassembling (does safety engage/disengage while the top receiver is off?).
I noticed in your pic in the other thread it was set to suppressed mode. Please ensure your valve setting is on normal mode (warning states NOT to shoot on adverse mode for an extended period of time).
Which buffer did your 516 ship with? (H buffer?)
Please post a pic of your bolt carrier from the front view on level ground.
I don't have one, but my son bought a 516 a year ago, we have never had a problem with that one. I'm not sure if they changed something or what. I was quite impressed with it, when he brought it out to the range. It was shooting the same ammo my DD M4 was just as well.
I just purchased the 516 and went to the range. The first 60 rounds pretty much fired without any issues. These were 5.56 ammo. Once I started firing the .223 ammo I noticed failure to feeds almost every round. Bullets were nose diving even when I cycle the gun by hand if you take a look at a round that chambers and comes out there are deep scrapes on the bullet. There appears to be a problem feeding ammo on these guns that sig has not owned up too. It appears a lot of us have this problem. Maybe just a bad lot or something. I trust sig will make it right if I have to ship it to them.
I shot numeorus .223 Hornady Steel Match 52gr and numerous 5.56 TAP 75 gr and they all worked as advertised. I kept the gas position in the 6/12 o clock position on my gen II for every range session. There are alot of mix ups both in sigs manual and sigs customer service rep who doesnt know as much about the 516 as people would expect. One of the lead designers had responded to a Gen II gas position mix up; he stated the 6/12 o clock position(medium sized dot) is the normal position. The larger the dot, the more gas is allowed through to the piston. The hole markers on the position switch show the respective hole opening size for gas bleed-through. If these guns are in the normal position, I have no idea what the problem is. My rifle and numerous other 516 rifles function fine with either .223 or 5.56 chambered ammo. Cheap .223 is another story as the powders and respective pressures produced by inferior powder cause issues. Yes, a gun that is supposed to be essentially an AK derived AR15 should be able to shoot anything as any AK47 would, but the 7.62x39 has much less pressure difference between cheap and "expensive" ammo if there is a such thing as expensive 7.62 x 39. The .223 and 5.56 have a much wider pressure difference. Thousands of PSI difference and that effects bolt cycling reliability. The only advice I could lend, is purchase 5.56 NATO ammo for this NATO chambered firearm. Might be hard to come by now, but when it is shell out the extra money and be rewarded with reliability.
On my gun the problem was with the feed ramp. It had a rough spot. If I used 223 ammo it would have a failure to feed. However, with 5.56 it would cycle fine I guess the extra power permited it to power on through the rough spot. It didnt matter what seletion the piston was set to with 223 ammo it would fail. The first Sig rep I spoke with had an attitude. However, I called back after trying what he suggested and spoke to another rep. They issued me an RMA polished the feed and so far it fired all 223 ammo without any issues and yes from the NORMAL piston position it DIDNT require adverse conditions. Sig turned the gun around in a fair amount of time less than three weeks and that included shipping so I'm very pleased and happy. I love this gun again . I'm even considering the 716 Thank you Sig!
Unfortunately this comes down to individual rifles having issues.... this isn't a ammunition issue at all.
I've shot .223 Federal American Eagle Tactical AE223 55gr through my 516 without any issue at all, and in fact it was the most accurate of the loads I tried.
I also shot Lake City M193 and Lake City M855, which also functioned flawlessly as well. Gas valve was set to normal for all shooting.
Next time I am at the range I plan on throwing some 5.56 NATO 55gr PMC X-tac XP193 through the rifle, along with some 75gr Hornady Match .223 Remington and 75gr Hornady Match Superformance 5.56 NATO. Will also try some 45gr Winchester Varmint to see how a lighter bullet does with the 1:7 twist.
My rifle is stock except for a BCM Gunfighter charging handle (large latch) and Timney Trigger with KNS Gen II anti-rotate trigger pins.
Build date is 02-21-2013 and picked up on 02-26-2013, has H marked buffer. I did notice that the BCG slid in the upper like it had been hand polished to no other, it was the SMOOTHEST I have ever felt any AR bolt carrier group move through an upper in my life.... and this was before it was even shot. Even when the bolt locked up it was very smooth, not even a close comparison to the Colt Hbar Elite or Troy Carbine I recently picked up. They both were pretty tight and was very hard to lock the bolt up before they were broken in, and even after broken in they both arent even close to the 516 (even before the 516 was shot). The chamber on my rifle is also obviously polished like crazy, its SUPER shiny and smooth. I guess that SIG is now polishing up all their 516 rifles to make sure they function without issue.
As far as the bolt lockup goes, I'm not sure if it has to do with the edges being radiused or not but it sure is a smooth lockup. Overall I love my 516, and am glad that I picked the one out of the 10 that I did. Serial is 501x.
A forum community dedicated to SIG Sauer Pistols and SIG Sauer Rifles owners and enthusiasts. Come join the discussion about optics, hunting, gunsmithing, styles, reviews, accessories, classifieds, and more!