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New 516 wont cycle

20K views 60 replies 29 participants last post by  Esox 
#1 ·
Just purchased a 516 rifle and took it to the range yesterday. The gun never jammed or double fed, but it would not cycle the next round on almost every round that was shot, and it would not lock the bolt back on the last round. I tried different mags and multiple brand/weight rounds,, but nothing did the trick. I changed the gas piston to the adverse condition setting and the rifle began to work as is should. Why is this?

I called Sig today and they suggested nothing. They said to send the gun in for troubleshooting and maintenance even though it is brand new. One thing I noticed is that my gas adjuster and the one shown in the manual look different. I'm assuming its the same concept though. Am I right?...12 o clock position normal and 10-4 position adverse?. Here are some photos ....Any help would be greatly appreciated. I would hate to send in a new rifle and not have it for the next 3-4 weeks.


1st pic- shows gun in normal mode- gun would not cycle or lock back on last round
2nd pic - gun in adverse (if Im correct). Gun cycled and shot perfectly, but per the manual the rifle should not be used in adverse setting for prolonged period of time.
3rd pic - The gas adjuster looks different than mine. Do I have a different version with different adjustment settings?
 

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#2 ·
You have second generation 516. If you call Sig they will send you an updated manual via email. However I saw on a different post the new manual has the piston drawing backwards. The 12 position is the normal and your second picture is the adverse. (In the manual they have the pictures backwards which causes a lot of confusion)

I just shot my second generation Sig 516 today for the first time where the piston was set to your first picture and I had no problems.

I did clean my rifle before shooting it the first time. I have read a few post that factory oil they use on the bolt is causing your issues. Try cleaning the bolt and reoil.
 
#6 ·
Ok I found the post. I hope this helps.

Question For SIG516 Owners: My SIG516 FDE Gas Block Is Different - AR15.COM




SIG Customer Service just called my cell phone and told me I was CORRECT! Apparently, just like I suspected, the pictures WERE INDEED SWITCHED by accident. Humans make mistakes, no big deal. The CS guy got the call from the local SIG516 expert on hand and told him they were switched. It's going to be changed before going to print.

Mystery solved. Vertical 12 and 6 o'clock position is Normal setting. 10 and 4 o'clock position is Adverse. End of story.
 
#55 ·
I'm still confused on this.
Before the first firing of my new 516 I looked at both the printed handbook and I downloaded the pdf from sig's website.
The pictures show the 12 O'clock position as normal. When I cleaned it After the first use I noticed 4 settings; the three drill dot's (small #1, medium #2, & large #3, and the "x" for gas off)
I put ninety rounds through the rifle with it in the vertical (12 O'clock position). The manuals plainly state this is #2 position for "Adverse". I thought I had done a bad thing and maybe damaged my rifle.
Now I read this and I don't know whats right. Do I understand you correctly that the manual is wrong. The #2 position is normal and the #1 (10 O'clock) is adverse?
I expect much better from Sig :(
 
#7 ·
Thanks

Ok thanks guys...I will clean the rifle and use a bit thicker lube. I will return the gas block back to normal (12o clock) position and try again at the range this week.


I hope this works as it feels like it can be a great rifle. However, it is a bit disappointing after seeing the marketing video of the 516 showing it being shoveled on dirt and mud and then firing without problems, but yet I need lube just for it to cycle .
 
#9 ·
I wouldn't go heavy on grease. I know guys who run their 5.56s right next door to dry or use one of the dry lubes from Sentry, like Tuf Cloth or Tuf Glide. They report no problems.

Myself, I'm a light-coat G-96 man. Or Ballistol if I don't have any G-96. The 551-A1 is humming along, printing well and looking good.

Let us know how it goes!
 
#10 ·
update

OK, so i cleaned the rifle as SIG customer service and the posters on this site have said and I am still disappointed. Here is the range report after cleaning and with the rifle set on normal position

American Eagle AR223 50 grain - Cycles every round but does not lock back on last round...4 rounds in mag

Remington 223 - 55 grain - cycles every round but does not lock back on last round...4 rounds in mag

Fusion 223 - 62 grain - Cycles every round but does lock back on last round..4 rounds in mag

Federal green tip penetrator .556 -62 grain - Cycles every round but it did locks back on last round..4 rounds in mag

Note: If I load the mag with only 4 rounds of any of the ammo brands that I listed it cycles just fine, but if I fill the mag with the full 10 rounds (California), it jams within the 4th or 6th round. I tried this with Magpul pmags and (2) different steel mags.

Here was my test:

Cleaned the rifle ...Magpul mag

American Eagle - 4 rounds
Remington - 4 rounds
Fusion - 4 rounds
Federal - 4 rounds

All rounds cycle but only Federal locks back

Swap mags

American Eagle - 4 rounds
Remington - 4 rounds
Fusion - 4 rounds
Federal - 4 rounds

All rounds cycle but only Federal locks back

Cleaned the rifle ...Magpul mag

American Eagle - 10 rounds
Remington - 10 rounds
Fusion - 10 rounds
Federal - 10 rounds

Either jams, double feeds, or does not cycle with the 4th or 5th round. None of the brands lock back on the last round.

Swap mags

American Eagle - 10 rounds
Remington - 10 rounds
Fusion - 10 rounds
Federal - 10 rounds

Either jams, double feeds, or does not cycle with the 4th or 5th round. None of the brands lock back on the last round.


What gives?....Nothing like the marketing video
 
#12 ·
I highly recommend that everyone clean their firearms, particularly ARs, thoroughly before shooting them the first time. The stuff they put on them at the factory is more of a long-term preservative to prevent rust while it's in storage than a lubricant.

Also, I stick with 5.56 ammo for my 516. That's the rifle's caliber, that's what it's designed for, so that's what I use. I've sent hundreds of rounds downrange on mine without a single hicccup.
 
#15 ·
I understand cleaning the rifle when I first take it out of the box. Not only did I clean it before the second range outing, but also cleaned it between each ammo test. There are multiple videos from sig showing the rifle dunked in mud, dirt, and water, so why is everyone putting so much emphasis on cleaning. God forbid I actually needed a rifle for defense I would not reach for my 516.

I'm still seeking advice on what I should do next because I really would hate to sell this thing and turn my back on sig.
 
#17 · (Edited)
There are multiple videos from sig showing the rifle dunked in mud, dirt, and water, so why is everyone putting so much emphasis on cleaning.
I don't think they can do the same with a brand new rifle...

I strongly believe in breaking a rifle in, I don't mean breaking the barrel in but the springs need to be softend.



Where is the brass landing after ejection? Picture your rifle as a clock with hands pointing at 12 (muzzle) and 6 o'clock (buttstock). If your rifle is properly set up, brass should land around 3 to 5 o'clock. If it is landing at 1 or 2 o'clock, your BCG is likely moving too fast to properly eject the brass (ie: over gassed). If your rifle is grossly over gassed, and the bolt is moving too fast then the bolt catch does not have time to lock it back after the last round.

http://archery.ar15.com/archive/topic.html?b=3&f=66&t=438640
 
#20 ·
I just got my 516 yesterday and cant wait to shoot it at the range this weekend. I'm going to test it myself. Im going to start out with american eagle .223bt then I'm going to move on to Federal M855 and see how this rifle performs. I will be using Pmags and I will clean the rifle first because there is some heavy grease in the chamber. I'm new to AR's and not too familiar with terminology. But there is grease on the barrel extension that is kind of thick. More than likely for preservation of the firearm before sale.
 
#21 ·
I am new to Sig 516 Precision Marksman. I have shot around 200 rounds through the rifle using 5.56 and 223 rounds. The 5.56 rounds recycle 99 % of the time without a problem. (That is, except for as accuracy) The 223 rounds, if using 62 gr or better, are far more accurate although still not to my expectations. Problem is, 223 rounds will not complete the reloading cycle and must be cycled manually. They continue to jamb and must be cleared many many times.
I had hope the Sig 516 was the answer to my hopes of having a great weapon Guess not.
Any help,
Thanks
 
#22 ·
New sig 516 will not cycle or stay back on last shot

just purchase the Sig 516 Gen 2..cleaned and oiled it then went to the range.
was totally disappointed...it failed to cycle at least 5 times out of 20 rounds, plus would not stay open on last shot.....went home to give it a deep cleaning and came back....was slighly better, but still failed to cycle 10 times out of 80 rounds, plus would not stay open on final round fired. Pretty disappointed to say the least...going to call Sig tomorrow and send it back for repairs. more later.
Bull 63
 
#23 ·
I do not have the 516 but I have the 716. The configuration of the Gas Valve on the 516 should be the same as the 716 except for the inside and outside diameter may be smaller. Take a look at the inside of the Gas Valve and inspect for residue powder obstructing the hole at the bottom. If dirty, soak the Gas Valve in solvent to remove any and all residue. It only takes a little build-up to restrict the escaping gas from the barrel to enter the Gas Valve. Also, the gas port in the barrel may be restricted with solvent based powder residue which will definitely cause the weapon not to cycle properly.
Clean the inside of the Gas Valve with a nylon or bronze brush with a cleaning patch wrapped around the bristles.
 
#24 ·
To Bull 63: After you remove the Gas Valve, you will see the different sized gas port holes. The gas exits the barrel from a hole in the barrel at the 12 o'clock position and enters the Gas Valve hole selected. If you have been cleaning the barrel with solvent with the barrel inverted, there is a very good chance the solvent has dripped out of the gas port hole in the barrel and into the matching hole in the Gas Block.
With the pushrod removed, place an empty case into the chamber and close the bolt.
Insert a piece of paper into the gas chamber and apply low air pressure into the barrel. With the chamber closed-off with the empty case, air should exit from the gas port hole of the barrel and into the gas chamber. If the paper moves, the gas port hole is clear, if not, the hole is restricted.
 
#29 · (Edited)
I bought the 516 a few weeks ago and when I took it out to fire first time it failed miserably. The first 10 rounds fired properly but after that it was ****. I cleaned the weapon thoroughly 3 times but it never improved. After the first 10 rounds it began cramming the new round from the mag into the star pattern on the chamber. It actually bent one round that way, then it began overriding the rounds, slightly pulling it out of the mag but not enough so the bolt severely dented the casing and ruined the shell. Next it basically went to single shot and wouldn't even touch the next round in the mag. Finally, it got to where it would fire the round in the chamber but not eject the casing. There was no recoil of the bolt. And yes, as I mentioned, I cleaned the gun repeatedly. I was shooting American Eagle 55grain. Couldn't try anything else because finding any ammo was hard enough. This was the only 5.56 ammo available at the time. I also tried 5 different mags. 3 Pmag's and 2 off brand. I should also point out that I did fire it on #2 position "Adverse" and it initially fired several rounds properly but then would only single shot.

I am not interested in talking to Sig CS or sending the gun back. It's obviously defective. I took it back to my gun store, who has a full time gunsmith, and he took it out back on the range and worked with it himself. He fired different size rounds from various mags and it would only single shot at best. He came back and agreed that it's toast. I am really glad I bought this at the LGS instead of internet because they just gave me a new one. I have not fired the new one yet but if it even hints at the same ****, they said they will take it back too. If that happens I will just get a Colt. After searching and reading about this I have found that many people are having the same or similar problem with the 516, while as many others respond and say their's worked perfectly fine. There doesn't seem to be an in between. I can't even begin to tell you what the problem is with the defective 516's but it's not ammo, it's not mags and it's not cleaning. Some of these 516's are fine while others are terribly defective. If you happen to be one of the unfortunate ones to get a defective 516, don't waste your time trying to make it work. It never will. Just take it back. I have to say, my opinion of Sig has gone down dramatically after this experience.
 
#32 ·
Update:
I took the replacement 516 out last weekend and it worked flawlessly. I ran 60 rounds through it without a hitch. Would like to have fired some more but at 70 cents per round there is only so much a guy can afford. Anyway the gun worked great. Did single shooting but also some rapid fire with no issues. The bolt set open at the end of each mag. Not a single issue with this gun. I'm feeling the love again a little bit.

When I cleaned this one I noticed that the gas valve and push rod (piston) assembly were much tighter. On the defective 516, the 2 parts practically fell apart on their own. With the replacement 516 the gas valve and piston assembly required a good bit of effort to pull apart. It has a very tight seal. Based on this, I am fairly convinced that the piston assembly on my first 516 was the defective part. I believe that something malfunctioned after the first few rounds and it could not compress the gas enough to cycle the bolt.

I wanted to share this and hope it is helpful to anyone else experiencing the same problem.

Dennis
 
#33 · (Edited)
thanks for the info dmspec, i have been having the same trouble with mine not cycling after the first round is fired from different magazines. We adjusted the gas valve to the large hole 10-4 o'clock and then proceeded to fire over 80 rounds with absolutely 0 jams or problems.

I'm worried that the 10-4 o'clock is incorrect and there is a warning message about continuing to fire from that position. When I checked this thread http://www.ar15.com/forums/t_3_126/...rs__My_SIG516_FDE_Gas_Block_Is_Different.html they said the pictures were backwards but then OP says 12-6 o'clock is the correct setting different from the "updated" manual says
 
#39 · (Edited)
thanks for the info dmspec, i have been having the same trouble with mine not cycling after the first round is fired from different magazines. We adjusted the gas valve to the large hole 10-4 o'clock and then proceeded to fire over 80 rounds with absolutely 0 jams or problems.

I'm worried that the 10-4 o'clock is incorrect and there is a warning message about continuing to fire from that position. When I checked this thread Question For SIG516 Owners: My SIG516 FDE Gas Block Is Different - AR15.COM they said the pictures were backwards but then OP says 12-6 o'clock is the correct setting different from the "updated" manual says
First I want to say that while I have been around guns and shooting/hunting all my life, I am a new AR owner. The 516 is my first AR and I have been an AR guy only since June of this year. One thing I have learned is that these are not deer rifles. These guns are precision instruments built with very tight tolerances. They require more attention. So everything I say below is based on my recent experiences. Not trying to be a know-it-all, when clearly I am not.

10-4 is the adverse position.

I have done a lot of reading on this 516 issue and almost 100% of those people having bolt cycling issues with the 516 say the same thing, which is that it works perfect or a lot better on adverse. So its obviously a problem with the piston's lack of ability to fully cycle the bolt. I would start by cleaning the **** out of it before ever shooting it. I don't know what that stuff is they put in there at the factory but I don't think its lube. It's dirty thick crud. So completely take the gun down and clean every inch, especially the bolt carrier group and the buffer spring/buffer tube. There is some nasty looking grease in the buffer tube from the factory and it needs to get out of there. If the buffer spring isn't working properly that could be 100% of the problem. Same for the BCG and piston assembly. Also, it doesn't need to be drowned in oil I don't think. Just a wiping of oil on the surfaces and a drop or 2 on moving parts.

There have been several guys that could not get their 516's to work no matter how much cleaning, no matter what kind of ammo, mags etc., (like my first one) and so what they did was take a set of wire cutters and cut the fist 2 loops (about 1/2 inch) off of the buffer spring. I have read this 3 or 4 times and each time they said the gun worked perfect after that. So perhaps the buffer spring is a little tight on some of these????

If possible I would tell anyone to do what I did and take the gun back to the store. The store owner can send defective guns back to Sig for credit so if they won't give you a replacement then you need to start shopping elsewhere. Just get a new gun and don't bother messing with one that is defective. That way you won't have to spend a fortune on ammo testing it and trying to get it to work. Not to mention being ****** off about it.

But if you bought it online or too much time has gone by or whatever, then maybe consider ordering a second buffer spring and cutting one of them down. That seems to be the issue for some guys.
 
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