AR15.Com Archives
 new bolt carrier group - cam pin "stuck"??
metroplex  [Member]
9/30/2004 3:59:41 PM EST
I can't seem to turn the cam pin at all, the manual says to do a 1/4 turn and lift, but its not budging. It's a brand new RRA bolt carrier group assembly.
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JoeInCT  [Team Member]
9/30/2004 4:16:45 PM EST
Have you removed the firing pin retaining pin and the firing pin?

uglygun  [Member]
9/30/2004 4:21:55 PM EST

Originally Posted By JoeInCT:
Have you removed the firing pin retaining pin and the firing pin?




+ 1


First time I went to take the bolt out it took me a good 5 minutes to remember that the firing pin needs to be removed before the cam pin will rotate allowing the bolt to be removed.
metroplex  [Member]
10/1/2004 12:04:29 AM EST


doi... thanks! I did forget to remove the FP!
gan1hck  [Member]
10/26/2004 10:03:47 AM EST
I just got a new bushmaster upper, and the cam pin won't come out. I have removed the firing pin and rotated the cam pin, but the top part is rubbing up against the gas piston. Tech rep says it should come out.

Any ideas?

Stickman  [Member]
10/26/2004 10:24:52 AM EST
Lube and wiggle....
az-gunner  [Team Member]
10/26/2004 3:22:03 PM EST

Originally Posted By Stickman:
Lube and wiggle....



Yeah, but what about his problem with the cam pin?
drjarhead  [Member]
10/26/2004 3:43:05 PM EST

Originally Posted By gan1hck:
I just got a new bushmaster upper, and the cam pin won't come out. I have removed the firing pin and rotated the cam pin, but the top part is rubbing up against the gas piston. Tech rep says it should come out.

Any ideas?




Turn the cam pin parallel to the gas key. Try rotating the bolt just a little to prevent the cam pin from binding on the carrier.
mongo001  [Team Member]
10/26/2004 3:45:53 PM EST

Originally Posted By metroplex:


doi... thanks! I did forget to remove the FP!



Learn as you go.
gan1hck  [Member]
10/27/2004 1:25:41 AM EST
Tried all that. There just doesn't seem to be enough clearance. I can see the metal marks on the gas key from the cam pin as it was pushed in at the factory, and I can't figure out how to get it out for cleaning.
metroplex  [Member]
10/27/2004 4:01:36 AM EST
Just to re-iterate:

I asked this question about a month ago and got the solution from y'all (thanks!!!)

In case anyone's just tuning in:
You have to push the bolt back flush against the bolt carrier so that the cam pin is exposed under the gas key.

Push out the cotter pin and remove the firing pin.
Rotate the cam pin 1/4 turn (it should rotate easily w/o much force) so that the head can be lifted out.

Try your best by wiggling and pulling. If there's SOME contact with the gas key, that means its not quite "aligned" and just keep wiggling.

One other question I have is: How is the extractor oriented? The extractor should be facing the ejection port side of the bolt carrier. If it's NOT in this orientation, then I fear the original manufacturer stuffed down the cam pin into the wrong side of the bolt and that may explain why its hard to rotate or remove.
otto_esq  [Team Member]
10/27/2004 4:32:06 AM EST

Originally Posted By metroplex:
Rotate the cam pin 1/4 turn (it should rotate easily w/o much force) so that the head can be lifted out.



Additional thing to try:

I have at least one new bolt/carrier set-up (unfired) that the cam pin will not clear the gas key if you turn it one way, but will clear it if turned 1/4 the other way.

I suspect that once my B/BC is fired a few times the parts will seat together enough that this won't be an issue.

How "new" is your RRA Bushmaster set? If all else fails, drip some CLP in the cam pin slot and shoot it. I bet it will come apart for cleaning then.
(just remember to reassemble the parts you've removed first.)

Cheers, Otto

BTW I had a friend of mine brag that he could still strip and reassemble an AR/M-16 rifle very quickly as he could years ago in the Marines, although he reportedly hasn't handled one in many years.
I didn't doubt him.
(1. its not that hard, and 2. USMC drill instructors have a way of instilling that skill FOREVER. DI Sgt. Carter (MCRD San Diego, 1989): you done good!)
BUT I made sure he had that particular rifle to strip.
Odds were 50/50, but sure enough he couldn't get the cam pin out. Time ticked by...
Eventually, he handed it to me and I handed it back just as fast with it out.
He stopped bragging, and I had to reassemble the rifle.
This story was for all you out there who wonder how old jarheads entertain themselves.

Semper Fi
Forest  [Team Member]
10/27/2004 5:43:10 AM EST

Originally Posted By metroplex:
...One other question I have is: How is the extractor oriented? The extractor should be facing the ejection port side of the bolt carrier. If it's NOT in this orientation, then I fear the original manufacturer stuffed down the cam pin into the wrong side of the bolt and that may explain why its hard to rotate or remove.



If you have a proper bolt & cam pin - the pin can only go in 1 way so the extractor will ALWAYS be oriented properly.
gan1hck  [Member]
10/27/2004 9:46:56 AM EST
Brand new Bushmaster upper. Only fired 60 rounds through it, and attempting to clean it the first time. I also own a Colt upper...have been shooting that one for 10 years.

I've tried all the suggestions other than shooting more. the cam pin just won't clear despite all efforts....I've even filed one edge of the cam pin a small amount in an attempt to clear the gas key.

No success.
brouhaha  [Team Member]
10/27/2004 10:03:51 AM EST
You did push the bolt back into the carrier so the cam pin isn't directly under the gas key, right?
gan1hck  [Member]
10/27/2004 10:54:41 AM EST
Yes
drjarhead  [Member]
10/27/2004 11:15:04 AM EST
If they got it in you can get it out.

do as noted above and take a small screwdriver or something similar and try to pry it out gently.

Oh, and while you need to turn and push the bolt into the carrier it has to come back out just a tiny bit.
M4Kid  [Member]
10/27/2004 12:07:20 PM EST

Originally Posted By az-gunner:

Originally Posted By Stickman:
Lube and wiggle....



Yeah, but what about his problem with the cam pin?



Think about this logically ...

The firing pin is actually a holding pin for the cam pin. The cam pin is actually a hold on the .... eh, nevermind.

shamayim  [Member]
10/27/2004 12:18:09 PM EST
Given that the cam is possibly oversized, your best bet may be to remove the gas key to get the original cam out, and then either eplace it, or file it to proper dimensions.

I assume that Rock River is still not staking the gas keys, so it shouldn't be too much of a hassle to get the key out. Even if it is stakes, you should be able to remove it W/O too much hassle Then, replace that cam
gan1hck  [Member]
10/27/2004 12:19:32 PM EST
Called tech support again today. After some discussion, it turns out that my bolt carrier key does not have the required relief cut in it, so the cam pin will not come out no matter what you do.

I thought I was nuts, but it turned out Bushmaster has some bolt carrier keys without the proper machining, and the cam pin will go in, but not come out.

Bushmaster is going to fix it for me.

Thanks, everyone.
M4Kid  [Member]
10/27/2004 12:26:37 PM EST

Originally Posted By gan1hck:
Called tech support again today. After some discussion, it turns out that my bolt carrier key does not have the required relief cut in it, so the cam pin will not come out no matter what you do.

I thought I was nuts, but it turned out Bushmaster has some bolt carrier keys without the proper machining, and the cam pin will go in, but not come out.

Bushmaster is going to fix it for me.

Thanks, everyone.



What the heck?! The pin goes in but doesn't come out?! Why? Is the machine cut like a funnel where it becomes smaller at the end or something? This is unheard of .... are you sure you didn't just try pulling out the pin? Also, can you twist it in the first place? Does it twist?
gan1hck  [Member]
10/27/2004 1:10:55 PM EST
If you look at the bolt carrier key head on, you will see that on the side the cam pin comes out, there is a cut in the metal.....ie it is not symmetrical....my bolt carrier key IS symmetrical...meaning my relief cut for the cam pin wasn't made. The cam pin rotates fine.

The way the bolt carrier key aligns with the cam pin allows the cam pin to slip in even if the relief cut isn't there....as in my case....I can actually see a small amount of metal wear on the side of the bolt carrier key where, I'm sure, the tech who assembled the bolt used force to push it in.

I've owned an AR since 1991, and have disassembled and reassembled the bolt carrier assembly hundreds of times over the last 13 years, so I'm pretty familiar with how it is supposed to come apart and go togethter.

This is my first Bushmaster, so I wasn't sure if there was some trick that I didn't know about, and it turned out that they sent me an improperly machined bolt carrier key.

Bradd_D  [Team Member]
10/27/2004 1:20:22 PM EST

Originally Posted By gan1hck:
This is my first Bushmaster, so I wasn't sure if there was some trick that I didn't know about, and it turned out that they sent me an improperly machined bolt carrier key.




Hmmm...
SkiandShoot  [Team Member]
10/27/2004 1:37:41 PM EST

Originally Posted By Bradd_D:

Originally Posted By gan1hck:
This is my first Bushmaster, so I wasn't sure if there was some trick that I didn't know about, and it turned out that they sent me an improperly machined bolt carrier key.




Hmmm...



Don't forget everybody ONLY TO BUY THE "ABC"S of AR-15s....


metroplex  [Member]
11/1/2004 7:13:33 AM EST

Originally Posted By shamayim:
Given that the cam is possibly oversized, your best bet may be to remove the gas key to get the original cam out, and then either eplace it, or file it to proper dimensions.

I assume that Rock River is still not staking the gas keys, so it shouldn't be too much of a hassle to get the key out. Even if it is stakes, you should be able to remove it W/O too much hassle Then, replace that cam



I have a RRA bolt and the gas key bolts are staked.
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