www.MG42.us

Heya

Whilst messing about my MG, the bolt got stuck in the camming piece, and it won't disengage. I've tried pushing down the muzzle many times to no avail (goes down for only a few centimeters at most). Any help would be appreciated.

"Whilst messing about my MG..." What does that mean exactly?

"the bolt got stuck in the camming piece" I don't understand how that can happen. The only function of the cams is to push the rollers inward when the barrel/bolt recoil together.

Did you mean that the bolt head is stuck in the barrel extension? The barrel won't push in? Did you take out the recoil spring when you took the flash hider off to push on the barrel bushing? Details please.

Not trying to be a technical pain in the butt, but you need to be clear about what happened and what level of movement you have now before a problem like this can be diagnosed.

JBaum wrote:Not trying to be a technical pain in the butt, but you need to be clear about what happened and what level of movement you have now before a problem like this can be diagnosed.

No worries, I appreciate the thoroughness.

I showed a mate how to change the barrel, after which I dry fired the gun. Now it simply won't budge from the barrel extension (not camming piece, like you said).

I removed everything of essence that I could, including buttstock and recoil spring. When pushing it in, it doesn't go further than what a flat surface pushing down on the barrel shrouds opening would allow. They pretty much line up. I'm not sure it is even supposed to be able to be pushed further. Either way, 90% of the time it bounces back, sometimes it stays until I push the bolt carrier back in. Even in the latter state, I can't remove the bolt carrier.

The bolt rollers are pushed in by the cams when the bolt/barrel recoils. This can be simulated by taking out the recoil spring and buffer, and removing the grip, then pushing on the barrel with a broom handle while someone holds the gun vertical and pulls on the charging handle.

The possibility also exists that the ejector bar is worn and has rotated inside the bolt housing. This happens when the ejector bar (inside the bolt housing) is a tiny bit short (20 thousandths of an inch?) from wear. If you can see the firing pin holder, you should be able to see the tip of the ejector bar sitting on top of it (top cover and feed tray off). If it's not visible, having it rotated inside the bolt housing allows it to block the firing pin holder from moving rearward, which blocks the rollers from retracting. If the rollers don't retract, the bolt head can't come out of the barrel extension. This can happen with a gun that's been fired a lot. It's one of the reasons that the ejector bar is a common spare part. It needs checked for length regularly by comparing it to a new ejector bar. The ends of the ejector bar actually wear until it's just short enough to not stay in place on the top of the firing pin holder.
The solution for this is to drill off (or grind off) the bottom of the pin (feed roller) that rides in the top cover channel. You can get to it from the bottom of the receiver with the grip off. Then remove the roller and get the ejector button in the rear of the bolt housing out. With the button out of the way, the ejector bar can fall out of the back of the bolt housing and allow the bolt head to unlock from the barrel. After drilling out the roller pin, replace the bolt housing. Be sure to mark the old bar with a grinder or something very obvious so you don't ever use it for anything more than a "this is too short" gauge.

Thanks for the reply! I was away from home, PC (and MG) for a few days hence the late reply. For the sake of being careful - how far down the barrel shroud should the barrel go in relation to the barrel shroud exit?

Sadly, I do not have a clear view of the firing pin holder. If it's not too much of a hassle, I could provide pictures.

How far rearward the barrel will go in the barrel housing is limited by the recuperator. If I remember right, the bolt starts to unlock after the barrel goes 7mm rearward, but has to go further, of course, to finish unlocking.

While holding the barrel rearward (as far as possible) with the top cover and feed tray removed, you should be able to see the top of the firing pin holder and see the forward edge of the ejector bar. If it is not there, it likely has rotated inside the bolt and is blocking the rearward movement of the firing pin holder.

Post any pictures you think will help.

John

EDIT:

I can barely get eyes on it if I look diagonally through the opening of the top cover. The firing pin holder is not visible. The square flat end of the ejector pin as well as the tip of the ejector bar against it, are.

If you can see the ejector bar, then that's not the problem.

So, with the recoil spring removed, and the grip taken off, the bolt won't unlock from the barrel.

Have you tried putting a block of soft wood (pine) on the ground and hitting the butt end of the receiver (gun held vertically) on the wood. This causes the barrel to go downward (recoil) and often will unlock a stubborn bolt.

Ratiasu wrote:Heya

Whilst messing about my MG, the bolt got stuck in the camming piece, and it won't disengage. I've tried pushing down the muzzle many times to no avail (goes down for only a few centimeters at most). Any help would be appreciated.

Do you even know what few centimeters mean? Bolt rollers 'must' unlock with only one centimeter of rear barrel movement. And maximum movement that the barrel can travel is 20mm that is two centimeters few centimeters means at least two. With MG upright push on the barrel bushing and let someone else with wooden stick and hammer strike down the rear of the bolt

Ahh, the ever unpleasant hakentt.

Saying that something "must" occur is only true under normal circumstances, without a mechanical malfunction.

His alternative method of getting the bolt unlocked may work and shouldn't damage the gun.

I've more than once gotten a bolt locked into a barrel extension and forgot to install the charging handle while building, though this isn't your circumstance, a method that works well for me is to place a towel on a hard surface (like your garage floor) and with the butt stock removed give the gun (rear receiver) a sharp rear downward tap on the hard surface and it will unlock the bolt from the rear inertia. I've done this with HK's and CETME's as well. Maybe try this.

OP probably figured it out by now and is not posting the cause of the lock. Very typical for new members here, they come with a problem, we all gather to help them out and they never post again.

Silly question but did he forgot to install the charging handle? Ive done that before, and felt like an idiot

Double post

hakentt wrote:OP probably figured it out by now and is not posting the cause of the lock. Very typical for new members here, they come with a problem, we all gather to help them out and they never post again.

I haven't yet solved the issue sadly. I only got back from abroad yesterday night, and like I said in the first post, have visitors over (he's been here for a few weeks now, went on a trip together, etc). I am terribly sorry I couldn't reply any sooner. I will get a more accurate description posted later today, as well as a picture or two which might help - though the angles make it hard to get anything worth getting on photo.

Will definitively also try the towel method mentioned here. Thanks for the advice everyone! This one has me puzzled to no end.

flemgunner wrote:Silly question but did he forgot to install the charging handle? Ive done that before, and felt like an idiot

The charging handle was installed, though I think by pulling it as much as I did, it may have slid into an unintended position. Its not connected to the problem with the bolt being stuck - just me using too much force plus wear and tear I assume. I have spare charging handles, so this one doesn't worry me too much.

Ratiasu wrote:

hakentt wrote:OP probably figured it out by now and is not posting the cause of the lock. Very typical for new members here, they come with a problem, we all gather to help them out and they never post again.

I haven't solved the issue yet sadly. I only got back from abroad yesterday night, and like I said in the first post, have visitors over (he's been here for a few weeks now, went on trips together, etc). I am terribly sorry I couldn't reply any sooner. I will get a more accurate description posted later today, as well as a picture or two which might help - though the angles make it hard to get anything worth getting on photo.

Will definitively also try the towel method mentioned here. Thanks for the advice everyone! This one has me puzzled to no end.

flemgunner wrote:Silly question but did he forgot to install the charging handle? Ive done that before, and felt like an idiot

The charging handle was installed, though I think by pulling it as much as I did, it may have slid into an unintended position. Its not connected to the problem with the bolt being stuck - just me using too much force plus wear and tear I assume. I have spare charging handles, so this one doesn't worry me too much.

Alright:

I doubt these will be of any use, but these are the best pictures I could get: https://pasteboard.co/GHF9Ryn.jpg https://pasteboard.co/GHFazi1.jpg.

As for the barrel, it sticks out of the barrel shroud opening by about one centimeter, and I can push it in for about 1.7 centimeters. As for the towel-on-floor suggestion, no dice so far. Just to be clear - I bumped the barrel inwards with a broom, and when it stays retracted, I pulled the charging handle. I made no mistakes here?

I appologize for my complete and utter lack of understanding (procedures, linguistic terminologies) in these matters.

Explain what you meant when you said:

"Either way, 90% of the time it bounces back, sometimes it stays until I push the bolt carrier back in."

The barrel bounces back so that it is in the forward position? Push the bolt carrier back in? In what? Do you mean you push it forward toward the front of the gun? Have you removed the grip?


How about a picture far enough away to see the whole bolt? Is this a full auto or semi gun?

Pictures from above are posted below.

As a last resort push on the front, with the flash hider off, against the floor. Take a piece of wood and hold it against the roller on the bolt. Hit piece of wood to the rear of the gun with a hammer. Bolt should come free. Oh yeah. Do this without a recoil spring in the gun

JBaum wrote:Explain what you meant when you said:

"The barrel bounces back so that it is in the forward position? Push the bolt carrier back in? In what? Do you mean you push it forward toward the front of the gun? Have you removed the grip?"

How about a picture far enough away to see the whole bolt? Is this a full auto or semi gun?

With the buttstock side on the floor, barrel shroud opening facing up, the barrel will be protruding from the opening of the barrel shroud. Pushing the barrel inwards will make the barrel go from sticking 1CM out of the barrel shroud, to about 7 MM into the barrel shroud. Once I stop putting pressure on it, it will usually it will bounce back to sticking out by 1CM. Sometimes it won't bounce back at all.

It's a full auto. everything has been removed apart from the cocking handle.

flemmgunner wrote: As a last resort push on the front, with the flash hider off, against the floor. Take a piece of wood and hold it against the roller on the bolt. Hit piece of wood to the rear of the gun with a hammer. Bolt should come free. Oh yeah. Do this without a recoil spring in the gun

Will do. Thanks!

It's hard to see from the pictures, but the ejector bar seems to be in the correct position. Any ideas what went wrong? Even if it turns out I'll have to send it to someone more capable at this than me, I would like to know what not to do in the future.

Ratiasu wrote:
It's hard to see from the pictures, but the ejector bar seems to be in the correct position. Any ideas what went wrong? Even if it turns out I'll have to send it to someone more capable at this than me, I would like to know what not to do in the future.

You have to get it out first then inspect the damage and maybe that will tell you what went wrong.