SigTalk is a forum community dedicated to SIG Sauer enthusiasts. Come join the discussion about Sig Sauer pistols and rifles, optics, hunting, gunsmithing, styles, reviews, accessories, classifieds, and more!
First let me say this is my first AR15 style rifle and that I cleaned all the factory gunk out and relubed it the same day that I bought it. I have about 500 rounds through my new 516G2 rifle (03.28.13 build date) and I'm having a couple of annoying issues. Let me say for the most part the gun performs very well. It is accurate, goes bang every time you pull the trigger (at least when a round is chambered), and has a strong ejection.
Issue #1:
I can almost never get the rifle to lock back on the last round. I'm using Federal white/brown box 5.56 55gr, PMC xtac 55gr, and CCI Speer Lawman 55gr. I'm using brand new Pmags (gen2 and gen3) and have tried about 6 of them (including the one that came with it). I don't have any USGI mags currently, but I would have figured the new Pmags would have worked well. After my range session yesterday I can only remember it locking back maybe twice. I have also tried using a new Sprinco enhanced spring and ST-T2 heavy buffer with the same results. I also have tried the normal and adverse gas settings with the same results. I am just having a tough time getting it to lock back after last round.
Issue #2:
I have an issue getting the rounds to cycle sometimes. It's not all the time, and it seems to happen most with the CCI Speer Lawman 55gr. Changing the gas setting to the adverse setting seems to fix this issue 100%, but then Sig recommends not to run this all the time. I'm not using **** ammo (at least I don't think I am). I would think the ammo I'm using would work fine on the normal setting. And some people say this issue might be a break-in issue and eventually the gun will loosen up. Well I'm probably at about 500 rounds now and still having issues. Ammo is not cheap anymore or readily available either.
I called Sig CS about 30 minutes ago and told them about the issues I was having. The first thing she asked me was what kinda ammo I was shooting and I told her Federal white/brown box, PMC xtac, and CCI Speer Lawman, and then she said what about ammo weight...and then I told her oh, they are all 55gr. Then she said that was probably the problem because this gun is really made for 62-65gr ammo. I was kinda puzzled by this because I have always thought that the 5.56 55gr brass ammo was pretty standard stuff and should be easily handled. I told her this info about not using the 55gr ammo was not in the manual and she said she was aware of this and that she wishes it was in the manual. She said that the 1:7 twist barrels are always going to do better with 62gr+ rounds. Has anyone heard this/agree with this or is this complete craziness? I told her that I would try some heavier rounds to see if that made a difference before I decide to send the rifle off. I mean she seemed nice and said that I could always send the rifle in if I thought something was wrong with it, but I figured I would post on here and see what others thought.
(I'm also starting to see reports on the internet of people having similar issues as me with their 516's and some are having a lot worse issues.)
This is my first Sig and I'm hoping I can get these issues resolved. Thanks!
So I finally got to the range again this past Saturday and tried some heavier ammo...PMC xtac 62gr and some Federal 62gr M855. Still having the same 2 issues....magazine not locking back after last round fired and I need to randomly put the rifle on the "adverse" gas setting for it to cycle properly on it's own. About 600 rounds through the rifle now and still having these issues so I would say something is definitely wrong.
I called Sig again today and spoke with Bill. He was very nice and told me I shouldn't ever need to run the gun in "adverse" using this kinda ammo, and should not be experiencing these issues (or any issues) after a 600 round break-in period. He emailed me a prepaid FedEx label and I got it shipped off tonight. So I'm hoping to get it back "fixed". I will continue to keep this thread updated with my progress.
wow....I wish I could look at it myself. Specifically the buffer system, the upper, the gas piston spring & the gas vent size & alignment. Something is definitely not right somewhere......I can't wait to see who dunnit'
Received my rifle on Tuesday (after a crazy mess with FedEx delivering it to the wrong address and actually letting someone else sign for it). I would say that's definitely good turn around time. The note from the Sig gunsmith said this:
Inspected rifle
Polished chamber
Adjusted gas rings on rod
Fired some XM855 ammo and functioned fine
Now I just gotta wait for some decent weather before testing it out at the range.
That's the part that changed something.....if it was fixed. It was a pressure issue; too bad you didn't take a micrometer to the gas system prior to sending it off.
So I was able to get to the range this morning and fired a few types of 55gr/62gr ammo (100 rounds). All functioned perfectly on the "normal" gas setting except for only one failure to cycle, so I'm happy with this. But I'm still having issues with the bolt failing to lock back on the last round. A guy at the range assisted me with this a bit and it's definitely an issue where the bolt isn't going back far enough. He said the tension was too high on the buffer spring and he recommended that I cut a coil or two off and that should fix it 100%. When I extended the stock out to the last position it did help some, but locking back is still random (maybe 50/50). I also tried putting in a new spring/buffer that I got and it had the same issues, but the new one is a Sprinco “BLUE Spring” ENHANCED Power Buffer Spring and the new buffer was a Spike's ST-T2. The Sprinco spring is enhanced power so I'm sure if it's a spring tension issue that would only makes things worse.
So should I try modifying the spring or do I just need to let Sig know again that the rifle still isn't running correctly?!?
hello im a new member here and joined due to problems I have had with my 516.the gun is on its way back to me.It was shipped back to sig for repair by the store I purchased it from.
The problems were
a-bolt only locked open after firing the last shot once in about 250 rounds
b-started having failure to feed problems with brass or steel case ammo(federal & pmc ) I believe.To go into detail a bit here is the gun would fire spit out the shell then with a live round hangining out of the ejection port the bolt would just slam on the side of the live round
I spoke to sig yesterday and they said they polished the chamber and feed ramp to correct this problem.They also informed me that they fired 60 rounds with no problems.
I didn't have that issue with the bolt slamming on live rounds. I only had some cycling issues where the next round didn't automatically advance (had to pull back charging handle everytime) and of course the issue with the bolt not locking back after the last round being fired.
The cycling issues seem to be corrected for the most part, but I'm still having trouble with the bolt locking back.
I got the rifle back today and it says polished feed ramp and polish chamber on the repair order.I will take it shooting Thursday and see how it goes.I looked at my ammo and I just realized that I have about 150 rounds of metal case 5.56 ammo.The sig customer rep.said not to use metal case ammo
update-Got the gun back Monday and took it to the range today.first 60 rounds no problems fed and fired-bolt never really lock open on mine after mag is empty.ammo used is IMI 62 grain
on the next set of ammo-various brass case 55 grain-the gun was erratic and wold fire then would have to pull the bolt back to clear and or chamber the next round-kinda like a bolt rifle.
Just to let you guys know any ammo that the gun would not fire -worked perfect on my friends Daniel defense m4.
Store I bought it from is sending the gun back to sig a second time.
I got my rifle back today from Sig and this time the gunsmith note said:
Inspected the rifle.
Cleaned up the trigger.
Polished the feedramp and the chamber.
Function checked.
Test fired at 10-7-5-3 round intervals out of the magazine and had no malfunctions.
I hope it's finally fixed this time, but I will say that it's a really nice trigger now. Before was definitely milspec gritty, but it's got a smooth/clean break now. Will report back again when I have time to go to range.
Ok so another range report after getting the rifle back from Sig the 2nd time.....
Tried a box of Federal XM855 62gr 5.56 with 4 diff mags (tested 2 rounds per mag each time)....flawless cycling, locked back every time (on normal gas setting). Things are definitely going good.
Then tried some Speer Lawman 55gr 5.56 again with 4 diff mags (about 10 rounds or 1/2 box)......flawless cycling, but bolt doesn't lock back on last around (on normal gas setting).
Then tried the Speer again, this time with adverse gas setting....flawless cycling and bolt locks back every time.
Then tried some PMC Xtac 62gr 5.56 on normal gas setting....flawless cycling and pretty sure bolt locked back every time but once.
So the gun is definitely doing better, might just be picky with some ammo.....not sure if I really want to send it back to Sig a 3rd time. I might just run it in adverse gas mode for the next 200-300 rounds to break it in even more than it already is (I have about 750 rounds through it now). The trigger is much better now, Sig did a great job on the trigger. Nice clean break now with no grittiness.
Do you guys think I should be ok running it for a couple hundred rounds in adverse gas mode? I know that Sig recommends that you shouldn't run it for very long that way because of premature wear etc. etc. but if that's the only way to get the gun to run 100% with some of my ammo I don't see another way around it (unless I need to complain yet again and send it back yet again).
It's pretty well lubricated already.....how much is "lots"? And what kind do you recommend, because I've been using only Fireclean to lubricate it? Should I just go with a standard oil like Mobil One or actually use a thick grease?
Your 516 is GTG now. Do NOT use too much lubricant, only contact points. Too much can attract dirt and build up over time. Plan ahead to avoid failures. I always use this as a guide as per what applies from the 516.
Please remember that cheap ammo will never guarantee last round bolt hold open (this applies for all weapons due to gas regulation sepecifications for that weapon). If you absolutely need LRBHO and if you have good ammo on-hand, always load the 1st round of every mag with good ammo that works on LRBHO, then load cheap ammo following it.
You say its pretty well lubricated already so like DresNightfire said, as long as you have the contact points lubed, you're good. Very good reference link he included also. Even though I never had any issues with my 716 I did give it a little extra lube until it was broken in just because I could tell it was tight. After a few hundred rounds through it I went back to my normal, which is pretty much exactly whats in the link above. And running it for a couple hundred rounds in the adverse setting won't hurt anything. Lots of guys are doing that until they're running fine.
Another range report....fired another 200 rounds or so on Saturday (a combination of PMC/Speer 55gr/62gr 5.56 and finally one box of PMC 55gr 223). I had the rifle set in the "adverse" setting the entire time for more break-in, and I didn't have any issues. Used 5 different magazines as well. The bolt locked back every time, cycling was perfect, and accuracy was very good as well. I did notice the hotter ammo extracted a lot further out than when on the "normal" setting, but I assume this is normal due to more gas being released into the rifle giving it more power when extracting. I might run another 200 rounds in "adverse" and then switch back to normal to see how it runs.
Zeeter- I hope all goes well! I hate to see a fellow sigtalk member buying a sig lemon! Good luck with yer 516! I really enjoy my M400 OD & 516 very much! Getting the 516 made me appreciate the M400 much more, because my M400 is a total stud! I even replaced the factory one(on my M400) to a "no name" brand M16 BCG from Palmetto State Armory, without any hiccups! The M16 BCG is so heavy that I could probably use it as a weapon to club someone.
Same issue here with fte/ftf. I bought the m400 classic and a 516. The m400 is awesome right out of the box, the 516, another story. It acts like a single action bolt rifle, I have to track it almost every time. I did love and clean, it was filthy with carbon. I did not touch the buffer shooting though. It is my first pain ar. I went home and cleaned it again and did the buffer. Have yet to test it again. While cleaning the upper, I noticed the feed Ramps weRe not aligned properly. Anyone notice this on theirs?
I want to make it as short as possible. Had all same problems with my 516. It went to Sig twice, they polished feed ramps, chamber etc. it did not help. Finally I went to local gun store and range and asked for help and advice (all advice from Sig were good for nothing). A young gunsmith looked at it and could not see anything wrong then he pulled out a action spring from extension tube. It was all covered with heavy, sticky grease. He took rifle to range and tried 10 shots and had same problems like I had, lock of feeding but mainly rounds stocked in chamber under angle all bent etc. He got back, pulled action spring out and said that it was a problem. Cleaned spring and receiver extension tube. Then just one drop of oil. Then we went to range. And....... All perfect, 5.56 or 223 no problems. I just could not believe it.
My fault, I did not clean it but Sig had my rifle twice.........
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
SIG Talk
2.6M posts
100.1K members
Since 2010
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!