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pulserifle99
05-25-2009, 2:42 AM
I have a Cmmg 20" upper ,i have had for sometime now, on a stag lower. I havent used my ar for some time, and when i went to the range i was having some problems with me bolt. When It try to strip a round from the magazine it the bolt doesnt seem to have the strength to strip the round from the magazine so it jams up about half way into battery. When i pull the charging handle all the way back again it will strip that round out completely and go into battery. But when i try to extract the round manually there is a lot of resistance coming out of the barrel. And twice it went into battery but pushed the bullet into the casing. I didnt fire it because the problems started occurring from the beginning. Also it is not the mag because i tried different ones. I am also not riding the charging handle. Sorry about the size of the pics.




http://i184.photobucket.com/albums/x36/pulserifle99/DSCN0555.jpg

SJgunguy24
05-25-2009, 2:52 AM
Did you clean your rifle after the last time you shot it? Has the B.C.G. been lubed? Most AR issues i've seen are cleaning related.

pulserifle99
05-25-2009, 2:57 AM
I have cleaned it, and it has been lubed. That was one of the first thing i thought of

SJgunguy24
05-25-2009, 3:12 AM
I have cleaned it, and it has been lubed. That was one of the first thing i thought of

Buffer tube and spring?

pulserifle99
05-25-2009, 3:21 AM
still having the same problems, what worries me the most is that sometimes when it goes into battery the bullet will be pushed into the case!

SJgunguy24
05-25-2009, 3:42 AM
Where is Lemoore? There is a guy who posts here named Randall, his calguns handle is AR15barrels. He's an AR whiz and he knows his s***. His website is the same name. The contact info says Mar Vista, I have no clue where that is but I would send my AR to him if I was running into trouble.

I'm an AK guy, my AR is more or less a novelty. I would trust Randall with my rifle, I think you'll find more who agree with me.

Nessal
05-25-2009, 3:57 AM
I dont think its the buffer and spring because if it has enough force to push the bullet into the casing it has enough force to push the cartridge into battery. Did you check the feed ramps to make sure nothing is out of spec? My initial thoughts were the mags. Try swapping a lower. That way you can isolate the problem more clearly.

NeoWeird
05-25-2009, 4:03 AM
Now the first thing that comes to mind is you mention you've had the upper for a while but say nothing about the lower. Is this an upper and lower that you have used in the past with success? Or is this a proven upper and lower it hasn't been used on yet?

pulserifle99
05-25-2009, 4:04 AM
I don't have another lower to try. What is supposed to be the spec on the feed ramp? Ive had the same upper and lower since the beginning

aplinker
05-25-2009, 4:57 AM
Where is Lemoore? There is a guy who posts here named Randall, his calguns handle is AR15barrels. He's an AR whiz and he knows his s***. His website is the same name. The contact info says Mar Vista, I have no clue where that is but I would send my AR to him if I was running into trouble.

I'm an AK guy, my AR is more or less a novelty. I would trust Randall with my rifle, I think you'll find more who agree with me.

He's going to look at the fact he hasn't shot the gun and tell him to stop playing with it at home.

NeoWeird
05-25-2009, 5:06 AM
Ok, now this is important.

DO NOT LOAD AN AR-15 IN YOUR HOME WITH LIVE AMMO!

The AR-15 firing pin is a floating firing pin with no spring to retard it's motion. The firing pin actually stops when it hits the primer on EVERY cartridge loaded and it DOES dimple them. It is VERY possible (read: it was a problem in the past that needed to have drastic changes) to set off a round by cimply chambering it if the cartridge is loaded with a soft enough primer.

That said, you need to whip the **** out of the charging handle and let the thing fly home. If it jams then start working backwards. What things have you changed since you last used it? New ammo? New magazines? Different magazines? Did you lube it? Was it not lubed last time? Did you use grease instead of oil? Did you store it loaded? Did you field strip it and clean everything to ensure you didn't have residual powders and solvents cake onto the surfaces? etc etc etc

The pictures are not clear enough for me to really see what's going on, but IF the bullet is getting set back into the case, do NOT fire them or the gun and have it checked by someone who knows more about ARs than you do. That is clearly an indication od the bullet making contact with another surface, like the barrel extension, and that slight set back can be VERY dangerous.

pulserifle99
05-25-2009, 5:14 AM
no, Its the same ammo I've always used, 62 grain lake city, the magazine is still the same 10rounder that ive had since i put the rifle together. i have field striped it before storing it, and it only sat for like 2 months. When i brought it out it still had some oil so I re-oiled it. And when i clean it i bust out the picks and scrape the lugs, bolt, ect.....

aplinker
05-25-2009, 5:24 AM
How much has the rifle been shot? 100rds? 1k? None?

pulserifle99
05-25-2009, 5:35 AM
I'd have to say a little over 1k rounds down the pipe since 06'

aplinker
05-25-2009, 5:38 AM
I'd have to say a little over 1k rounds down the pipe since 06'

And it just started this or always did it?

Does the rifle jam when you're shooting?

pulserifle99
05-25-2009, 5:43 AM
Its never done this as far as I can remember. I noticed it today at the range after it sitting for about 2 months

VaderSpade
05-25-2009, 8:13 AM
Misread the problem.

aplinker
05-25-2009, 9:24 AM
I was having the same problem. This fixed it; http://www.calguns.net/calgunforum/showthread.php?t=186910

An extractor has nothing to do with feeding.

Vtec44
05-25-2009, 9:55 AM
When It try to strip a round from the magazine it the bolt doesnt seem to have the strength to strip the round from the magazine so it jams up about half way into battery.

What exactly does it mean when you said "when it try to strip a round from the magazine"? Does it mean that after a round is fired, extracted, and ejected, the BCG comes back and tried to strip around from the magazine but can't?

pulserifle99
05-25-2009, 5:06 PM
well i havent fired it because of the bullet being pusherd into the case. but im talking about when i load the mag and try striping a fresh round for the first time

SJgunguy24
05-25-2009, 5:12 PM
Have you sent AR15barrels a P.M. yet?

ar15barrels
05-25-2009, 5:24 PM
well i havent fired it because of the bullet being pusherd into the case. but im talking about when i load the mag and try striping a fresh round for the first time

How many rounds in the magazine?
How many rounds is the magazine designed to hold?

!@#$
05-25-2009, 5:32 PM
reloads?

pulserifle99
05-25-2009, 7:41 PM
Its a 10 round C products mag. they are not reloads as far as i know

Vtec44
05-25-2009, 7:43 PM
Try putting 9 rounds.

aplinker
05-25-2009, 8:15 PM
Its a 10 round C products mag. they are not reloads as far as i know

If it's just the 1st round, C-P are known to be damned tight. That would make it have issues on loading the 1st round.

pulserifle99
05-25-2009, 8:15 PM
well it happens with all the rounds from the 1st to the last

Josh3239
05-25-2009, 10:35 PM
It doesn't sound like a bolt problem. From what it sounds like, the bolt isn't feeding rounds when you move the actions manually. My first thought is if the magazine is seated correctly. The first thing I would do is get a different magazine, listen to it lock into place, push it in (some people like to smack the bottom but I wouldn't recommend that) and pull down to ensure it is seated correctly.

pulserifle99
05-26-2009, 2:40 AM
While i was inspecting my upper, i noticed a small gouge or chip in the metal here the bullet feeds. I have no idea how it got there, but I assume it could lead to the round hanging up on there possibly leading to the round being pushed into the case. It is a cmmg upper, do you think they have some sort of warranty that might cover this? Here are some pics

http://i184.photobucket.com/albums/x36/pulserifle99/DSCN0557-1.jpg
http://i184.photobucket.com/albums/x36/pulserifle99/DSCN0556.jpg
http://i184.photobucket.com/albums/x36/pulserifle99/DSCN0557.jpg

NeoWeird
05-26-2009, 5:09 PM
If that were the case it would feed every other round as it feeds from the opposite side of the magazine. Plus, if material were missing it would be LESS things in the way - not more.

While that may be a problem, I don't think fixing that alone will be the solution, especially if it's happening EVERY round.

aplinker
05-26-2009, 8:16 PM
If the pics were blurrier that might help. ;)

Are those M4 ramps with a rifle barrel extension?

GTXR390
05-26-2009, 8:18 PM
i've had that issue happen, but it was one of my C-Products 10rnd mags.

I also notice on one of my Stag's that, the feed ramp, isn't perfectly smooth...well, at least where...kinda hard to explain.

if you see where your brass markings are on the feed ramp, right below it where the two metallic parts meet, that's where it's a lil curled up, very slightly, however, i've never had any feeding problems, except for the bad mag.

I think you should call CMMG, and get a new upper, if that's possible...make it easy on yourself. or at least have them fix it, it's got a lifetime warranty, right?

GTXR390
09-23-2009, 9:51 AM
any updates? fixed the issue?

Beelzy
09-23-2009, 12:34 PM
It has to be the mags.

They make them cheap as chit anymore.