Armalite AR10 stuck cam pin.

[PandaBearBG]

Hows it going guys, a friend of mine recently puchased a new Armalite AR10 off of gunbroker, about 100 rounds down the pipe by previous owner. When he was stripping it down for the ritual first cleaning, he found that the cam pin was stuck, it still rotated and moved pretty freely but is literally stuck under the bolt carrier gas key and it just won't come out. He's tried every which way and short of wrenching it (which he wont do) it just won't clear the bolt carrier. He called Armalite and they didn't have an answer for him either short of buying a new one (which he would like to avoid). Any advice or secret techniques guys to help him out so he can strip his bolt.

The fire fires and cycles fine for him, everything works perfectly he just can't disassemble the bolt.

 

[FLAvalanche]

I'm confused...

When the cam pin is turned it doesn't clear the gas tube or it does clear it and is simply won't come out?

 

[rcmodel]

It would seem if the cam pin won't clear the key once the firing pin is removed and the cam pin rotated 90 degrees, you might have a defective bolt carrier.

Something has to be preventing the bolt from rotating all the way to locked position to allow the cam pin to come out.
That something would almost have to be a mis-cut cam slot in the bolt carrier.

rc

 

[PandaBearBG]

FLAvalanche - it turns but does not clear the gas key, literally a millimeter too big, no matter which way it is turned and pulled (by hand) the thing is stuck.)

rcmodel - So does he replace the bolt carrier gas key? Or if he shaved off a little of the head of the cam pin would that work? Is that safe? or do you think that he should get a whole new bolt carrier? My friend is on a very tight budget and does not really have the funds to get a new bolt and properly headspaced right now.

 

[onibaba]

If the bolt turns and moves in and out of the carrier as it is supposed to, there should be enough clearance. Oil the cam pin and bolt first.

The picture shows that the bolt is not turned completely. I'll assume that if it fires fine then the action is turning the bolt and moving the bolt forward and backwards correctly.

It shouldn't hurt if you carefully grab the bolt with channel lock and turn it completely. Wrap it first with a towel.

You should then see that you have enough clearance to pull the cam pin. Since its stuck, use a screw drive to pry it upward. If you are careful it will not hurt the cam pin, bolt or bolt carrier. Its not that fragile.

If something is stuck in there and preventing it from being extracted, then it is already ruined and pulling it will only help you determine why its stuck and what need replacing.

Lack of oil is probably the culprit. Just be sure it gets turned all the way before applying leverage with a tool.

 

[PandaBearBG]

onibaba - the cam pin turns freely 360 degrees and has vertical play in freedom of movement. The picture was bad, it was just to describe the problem, there is an audible click of metal on metal as the cam pin is pulled up and hits the gas key. We will try the channel lock but we are just afraid that the gas key will be damaged or misaligned if we forcefully pull the cam pin out. But we are just wary of any damage doing so may do. Has anyone know of anyone who has experienced this problem?

 

[BBBBill]

Can't tell from the pic and you didn't specifically say so. Did you remove the firing pin?

 

[rcmodel]

Take a plastic hammer or block of wood and a steel hammer.

Now, smack the bolt face and drive it all the way to the rear against the bolt carrier.

Perhaps some carbon or a broken gas ring is keeping the bolt from fully seating.

I suppose the ideal way to get it apart would be to remove the gas key first.
But that involves re-staking the screws when you put it back together.

Regardless, you have to get it apart to find out why it won't come apart and fix it.

rc

 

[rbernie]

I have had this happen before. In my case, the gas key's forward extension was shaped like an upside down U, and as a result the bottom edge did not have enough of a bevel to allow the cam pin to be removed. I can only assume that the key was installed after the bolt was installed into the carrier.

Rather than remove the key and replace it, I elected to use a file and knock off the bottom left edge on the gas key (looking at it from the rear of the carrier) to provide the needed clearance.

 

[onibaba]

onibaba - the cam pin turns freely 360 degrees and has vertical play in freedom of movement.

Then the cam pin doesn't need to be pried out.

there is an audible click of metal on metal as the cam pin is pulled up and hits the gas key.

This indicates that the bolt is not fully seated to the rear and completely turned allowing for the necessary clearance, or something is abnormal. In the case that its not fully seated to the rear, either smack it as RC described or carefully turn the bolt while pushing it to the rear with channel locks.

Look to see if the cam pin is touching the clearance cut out on the bolt carrier. If it is touching the side of the hole some is abnormal.

We will try the channel lock but we are just afraid that the gas key will be damaged or misaligned if we forcefully pull the cam pin out.

Do not force the cam pin out if its touching the key!

If its touching like you say it would be better to do as RC described:

the ideal way to get it apart would be to remove the gas key first.
But that involves re-staking the screws when you put it back together.

You might be able to remove the allen screws without actually deforming the staking. Unscrew a little of the first one, then a little of the second one etc. until it comes off.

It will be far better to remove the key that way or fully pull the allen screws then to deform the gas key by forcing it out.

Onibaba