G3 bolt problems?

[windigo]

So I am new to this forum and have a question for you guys. I posted it over on surplusrifle.com, but there's only been one answer and it wasnt very helpful. I understand you guys know these CETME/G3s inside and out, so you can probably help me a lot better.

Two years ago, I bought a G3 from a local hardware store that has a cast alluminum receiver from Federal Arms Company. It came with an alloy mag that wouldnt feed rounds, so I bought a steel one and that fixed the problem.

I never had any problems other than the alloy mag failing to feed. Recently though, I had the G3 out and was shooting it and then suddenly it stopped firing. It would strip rounds off the magazine and chamber them, but the firing pin wouldn't impact the primer or there would be a very slight primer dent. I broke the gun down and looked at the bolt and everything seemed fine, so I reassembled it and tried firing again. Same thing, strip a round off the mag, fail to fire, eject the round with the charging handle, fail to fire again.

I have the gun broken down in my basement. I cleaned and looked at everything I could think of. I cleaned the bolt completely and inspected it for problems. I disassembled and cleaned the charging handle in the gas tube (frustrating to reassemble). I even cleaned out all the gunk from the chamber and the trigger group and cleaned and lubed the recoil spring on the stock.

I still have the problem. What happens is I pull the charging handle back and lock it into the catch. When I slap the handle down to close the bolt, it flies forward just fine, however there is a visible problem with the bolt. You can see on the ejection port that it doesn't close all the way. When you flip the gun over and look in the mag well, you can see there is a 1/4" gap between the back of the bolt and the bolt carrier. Something is keeping the bolt from closing and the rollers from locking completely. When the bolt is out, it takes very little effort to get the bolt to lock, but in the gun when you charge it, something keeps it from happening.

Sorry for the long description of the problem, but the more details the better, I guess. I'm just hoping that you guys have a theory about the problem and an answer about how to fix it. If you want, I could post pictures showing exactly what I'm talking about, but I'd have to find my digital camera first.

[jfowl31]

Its time to start trouble shooting...

first, check your recoil rod and make sure that sucker is DEAD STRAIGHT... if its bowed, it could be binding the carrier up and not allowing it to lock in completely.

If you got that sorted out, and its still broke, try taking off the grip frame and charging it. if it loads fine, then your ejector is probably riding too high and binding on the bolt. You can file it down or buy a new one from RTG parts.

if thats not the problem, then maybe your recoil spring is too weak. I believe RTG sells new recoil springs too, but your just as well off buying a cheapo G3set from CTD, and swapping out all the internals if your buffer is worn too... Or you can just get a new spring and throw it on there.

It also could be that you have something protruding inside the receiver thats slowing down the bolt too... Be glad it didnt fire out of battery or you wouldve been dealing with a straight blow-back 308. no bueno.

hope you get it sorted out.

p.s. hows the aluminum receiver holding up over time? how many rounds do you have through it... that kinda stuff...

[rustypirate]

Also check the chamber for any obstructions like a piece of brass stuck in there. Try inserting a cartridge into the chamber by hand and see if it goes in all the way (about 1/8" should remain protruding from the barrel).

Is it easy to remove the cartridge once the bolt fails to lock in or is it stuck?

Check to make sure that the roll pin in the top of the bolt head is flush with the bolt head.

You say that you have cleaned the bolt, but did you inspect the rollers and locking piece? You may have a broken roller retaining plate or firing pin.

Quite often there is build up of carbon in the trunion around where the rollers lock in, check that too.

[Perro]

Check to make sure that the roll pin in the top of the bolt head is flush with the bolt head.



it is not supposed to be flush with the bolt head unless it has been modified from original

if it is driven too far into the bolt head, it will bind the locking piece

when driving the roller retaining pin in, you need to have the locking piece fully inserted in the bolt head before doing so. The roll pin will then bottom out on top of the locking piece, but most stick above the bolt head just a small amount

if you drive a factory sized pin flush with the bolt head, the locking piece wont be able to enter the bolt head

check it though, just make sure you have a locking piece inserted all the way in pushing the rollers all the way out before tapping it in.


show him the picture of the rails compared to the trunnion - this would be another thing to look for. Since the aluminum receiver isnt welded to the trunnion, its possible the aluminum might have expanded a bit?

[rustypirate]

My apoligies, I should have said to make sure that the roll pin was not out too far and binding on the trunion.

[Perro]

no appologies necessary Mr. Cat
only trying to save him a few extra headaches - nothing more

didnt you find the rail problem rusty?? dont you have a photo of what the rails are supposed to look like compared to the trunnion?

[windigo]

I went back to the rifle after looking at replacement parts. Now I feel like a real idiot. I noticed that the spring in the charging handle does not look like the replacement spring. Mine has one side thats full length, and the other looks like it has been bent and cut. The charging handle wobbles and doesnt smack right back down against the gas tube.

I took the charging handle apart again and removed the spring. I unwound a coil from the short side, straightened it out, and altered the angle it was at. After that, I refit the spring into the charging handle and carrier, made some minor bends in the spring to make sure it wasn't going anywhere, then I clipped it to length so it doesn't protrude and catch on the gas tube. I reassembled the weapon, pulled back the charging handle and locked it in place. Gave it a smack and the bolt flew closed with no problem. Did it 20 more times and the same thing.

I guess it's always the simple things that screw us up. I'm glad it was a problem that I could solve, and it feels good to know that I was able to.

@jfowl: I havent put many rounds through it myself. I've shot 4 South African battle packs and maybe 3 boxes of commercial .308 through it. My only complaint is the receiver is big and ugly. Its not slim and fitting with the gun like a stamped receiver.

Another question for you guys: Is this gun supposed to destroy the mouth of the case? When I find my ejected shells which fly a good 30 feet away, the case mouth has been smashed in on one side. Is this normal, or is there a problem?

[Perro]

normal

[windigo]

Guess that means I cant reload its shells...

Can I shoot steel cased rounds like Wolf in the fluted chamber?

[rustypirate]

no appologies necessary Mr. Cat
only trying to save him a few extra headaches - nothing more

didnt you find the rail problem rusty?? dont you have a photo of what the rails are supposed to look like compared to the trunnion?


Yeah, but those cast aluminum FAC receivers are so thick at the sides that I would not think they would suffer from that problem.

[jdlilfan]

Guess that means I cant reload its shells...

Can I shoot steel cased rounds like Wolf in the fluted chamber?

Yes you can. It will beat steel case rounds up as well.

[windigo]

Thanks for the answers, guys. I guess I should order a case of Wolf then, since it seems to be the cheapest ammo right now.

[TS308]

windigo

good thing that one reply helped you out .. im still learning my Cetme but ive read alot and i now understand the sytem to the point that i will be purchasing another one of them .

TS