View Full Version : AR problem or user error.?

12-08-2010, 4:16 PM
Shot my new sig 516 today for the first time. I get to the range load up my mag, the damn thing wouldn't lock into the gun it just kept falling out. I don't know what I did to get it to stick in but a minute of fiddling with it I got it to stick. Take off the safety, pull the trigger, click but no boom..WTF..pull the charging handle back, the bullet ejects and a new one goes into chamber, pull the trigger, boom boom boom no problems. (looked on the first bullet the firing pin didn't hit it). Eject the mag stick a new one in. It locks in this time, I hit the button on the side to release the bolt forward, a bullet goes in the chamber, pull the trigger, again click but no boom (firing pin didn't hit the bullet again) pull charging handle back bullet ejects a new one goes in boom boom boom all good.
Shot about 200 rounds today. About 80% of the time the first bullet in the mag wouldn't fire. The firing pin didn't hit the primer. About 25% of the time after releasing the mag the new one wouldn't go all the way up in the gun, I had to pull the charging handle back while pushing up on the mag for it to go up the 1/8th inch more it needed to lock in, again probably 70-80% of the time the first shot was just a click no boom.
I pulled the bolt out to see if there was any weird markings on it like something wasn't functioning right but the bolt looked fine. Near the end of the day I noticed my bullet button screw was backing it self out, I figured that might be the prob. I tightened the screw back up but it didn't fix the problem.
So am I retarded or is my gun retarded..?

12-08-2010, 4:31 PM
Are you loading the mag with the bolt back and locked? That should take care of this. There've been numerous thread about difficulties with mags/feeding - the common denominator is usually loading a mag on a closed bolt.

As to the 1st shot not firing, pull your BCG apart and clean the inside of the bolt under the bolt-face where the firing pin sits, and clean the firing pin.
That it only happens on the first round it would seem to be a cocking problem or that the firing pin is already moved toward/stuck to the bolt-face and the hammer isn't generating enough force to set off the primer.

12-08-2010, 6:14 PM
You didn't say what magazine you are using but many of the blocked magazines (10/20 or 10/30) are so tight on a full magazine that they are nearly impossible to put into the rifle. When you let go of the charging handle the bolt doesn't close properly because there is so much friction against the cartridge going into the gun and the other cartridges in the magazine. If this is in fact what is happening you can either; not fill the magazine all the way, get a new magazine that isn't quite so tight, or possibly use the forward assist to make sure the bolt is really fully closed on the first shot.

12-08-2010, 6:25 PM
List types for mags you were using. If possible post some pictures of your trigger and BCG.

12-08-2010, 6:34 PM
I have a magpul 10/30 that's rivited and a 10 round that says C Products LLC, newington CT. The gun wouldn't fire the first shot on full mags on either mag, I thought about the tightness your talking about so I tried once or twice to only load 8 and 9 bullets and it still wouldn't fire the first shot sometimes. It fired the first shot the couple times I only loaded them with 5 rounds.

What exactly does the foreword assist do..?

My buddy told me it's for helping unjam the gun.

Once today when my other buddy (first time shooting a gun) was shooting the first shot didn't go off and when he pulled the charging handle back to eject the bullet, the bullet was stuck in the chamber and he released the charging handle jamming another round into the one stuck in the chamber. The mag wouldn't come out until I pressed the forward assist, that freed up something and took pressure off the jam and the mag came out with ease.

12-08-2010, 6:35 PM
I took some pics of the bcg but I'm on my phone right now. I'll upload them when I get home.

12-08-2010, 6:52 PM
Here's what I would do.

1.) Take one mag. Go ahead and load 1 round into it. Lock the bolt back and insert the mag. Release the bolt and see if the round strips off the mag and the gun fires.

2.) If that works, I would go ahead and load 5 rounds into the same mag and repeat.

3.) If that works, I would go ahead and load 10 rounds into the same mag and repeat.

4.) If all of those work, go to another mag and repeat. If it doesn't, repeat with the other mag to see if it is the mag.

5.) If it works with one mag and not the other, then it is a mag problem. If it doesn't work with both mags, then it is possible it is a rifle problem. If it is a rifle problem and I'm assuming that it is brand new, I would recommend contacting Sig to see if they can be of assistance. Since I'm also assuming that you brought a new rifle, I would suggest getting them to fix any potential problems instead of you doing it yourself.

By the way, the malfunction you described is what is called a double feed. The suggested way to clear that is to lock the bolt back, drop the mag, rack the charging handle to extract the round, reinsert the mag, and rack the charging handle (or at least that is how I was taught).

12-08-2010, 6:55 PM
Also make sure you don't pull the charging handle back, and then ride it forward. Let it carry its own weight forward under the recoil spring. Then tap the forward assist, which is for putting the bcg into battery.


12-08-2010, 7:01 PM
OP did you clean your new SIG516 before shooting?

12-08-2010, 7:02 PM
Im almost positive if you were to check your bolt on the first round, you will see that it isnt fulling forward. In this case, hit the forward assist and be on your way. This would most likely be caused by a magazine related issue, like someone said earlier, depending on the mag, you can have to much tension on the top round and it can cause an issue similar to what you are encountering.

Try loading 9 rounds into the mags

insert mag with bolt locked to the rear

slap bolt catch release

visually verify bolt is fully forward

push forward assist for good measure


safety off


12-08-2010, 7:42 PM
No I didn't clean it b4 shooting it. I inspected it before shooting. It was squeaky clean with an assload of lube straight from the factory.

About the dbl feed. I don't know how to lock the bolt back or I would have done that for sure. I knew there was an easier way. I held the charging handle back, and hit the forward assist while my buddy pulled the clip out. I'm a total AR noob but I've been shooting hunting rifles, pistols and shotguns since I was 8 years old.

I never rode the charging handle back I just let it do it's thing but never hit the forward assist after. I did make sure the charging handle was all the way forward tho.

I'm going to go shoot it again on Saturday, I'm pretty sure after reading you guys advise I should be able to locate the problem or eliminate it all together now that I'm a little more experienced with the rifle.

12-08-2010, 7:51 PM
If you want to lock the bolt back, you use the bolt release. There is a little nub on the bottom of the bolt release that will lock it back. The way the bolt release works is that the top paddle like thing will release the bolt while the bottom part locks the bolt back.

The way I run my AR is that I don't actually use the charging handle a lot. I'm usually letting the bolt lock back on an empty mag and then using the bolt relase to drop the mag.

Have you thought about signing up for a training class for carbines?

I have taken two classes with my AR and found that it really helped me learn about malfunctions, shooting it well, and running the gun overall.

12-08-2010, 7:56 PM
No I didn't clean it b4 shooting it. I inspected it before shooting. It was squeaky clean with an assload of lube straight from the factory..

That's not lube. Clean all that gunk out. That's packing grease designed to keep the rifle from rusting while in storage from factory until user buys it.

Once it's clean, then lube it.

12-08-2010, 7:58 PM
I would be interested in taking a class for sure. I gotta look into that as I have no idea where they offer those classes in my area. I'm in the Vallejo ca area..anyone know of a good course in my area..??

12-08-2010, 8:02 PM
There was a little grease here and there but most of it I think was an oily lube because its really thin and seeping out of every nook and cranny from the outside of my gun. But like I said I'm a noob I could be wrong

12-08-2010, 8:04 PM
I should just clean it anyway and relube it. It came with a little tube of Mil-Comm TW25b

12-08-2010, 8:14 PM
ya its packing grease but no worries get it cleaned and oiled up like it should be and +1 on taking a class it would be a good thing to do being that you are new to ARs. they arent like a bolt action or shotgun its a whole new world. they are a lot of fun though but make sure you learn how to handle, operate and maintain your rifle. take care of the things that take care of you. be safe and have fun

12-08-2010, 11:50 PM
I don't know how to lock the bolt back or I would have done that for sure.

After you're shown how to lock the bolt back, load the mag with the bolt locked. Press the bolt-release to send the bolt forward and chamber the round. Should have no problem. :cool2:

12-08-2010, 11:59 PM
the little lever you press when the bolt is to the rear to slide it forward after you have shot your last round push the opposite end of that same lever down as you pull the charging handle back

12-09-2010, 9:27 PM
I would be interested in taking a class for sure. I gotta look into that as I have no idea where they offer those classes in my area. I'm in the Vallejo ca area..anyone know of a good course in my area..??



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