MG34 Runaway....

[URAR1004]

I just got back shooting my friends MG34 Pre Sample, and it started running away mabe 30+ rounds before it would stop, I'm not too familiar with the 34, and I'm still learning, what could fix this problem? Thanks for any advice or direction.

[helix60]

Sounds like the sear in the bolt head is sticking. I've run across a number of bolts with this problem either from long term storage with Euro Grease. Or a worn and galled pivot pin. I haven't run across many worn sears or broken springs.

Regards,
Heli

[URAR1004]

Sounds like the sear in the bolt head is sticking. I've run across a number of bolts with this problem either from long term storage with Euro Grease. Or a worn and galled pivot pin. I haven't run across many worn sears or broken springs.

Regards,
Heli

I'll take the bolt aprat and clean and chek the pivot pin. I'll let you know what I find out! Thanks for the help.

[Blanksguy]

If the MG34 worked prior to the last range-outting...there are a few items/areas to check which I have listed below.....but your initial post/question said the Mg34 "...and it started running away...." Which sounds like a component just starting to go:

FIRST: SAFETY:
REMOVE AMMO_BELT AND CLEAR THE WEAPON and CHAMBER....then:

Items to check (but are not limited to) would be:
1: Weak sear-spring.
2: Worn/rounded catch-edge on the sear or botom of Bolt.
3: Booster coming lose and/or bullet-exit-hole starting to wear larger.
4: Operator Training:
Were you trying to fire the weapon without supporting the belt either in an assault-drum or the aid of an assistant-gunner ? The MG34 has a weak "lift" for the feeding-system.
When you pull the trigger.....do you pull the trigger firmly and all the way (?).....or just "ease it to the rear" and slowly release it when you want to stop firing (?)
5: Possibilities of the buffer starting to come apart (?)
6: Improper-lubrication and/or dirty weapon.
7: Something "dragging" in the system to cause the bolt to not fully recoil....but allow enough recoil to eject the spent cartridge-case. Does the ejector "kick" the fired case out hard (?)...or does it just drop out during firing (?) Does the ejector-rod have free-movement in the bolt-head....or does it "stick" and hard to move (?)
8: Slightly bent Top-Cover......if it is flipped over a close rear-sight....and pressed down, the center of the top-cover will "bow" downward in the center when re-closed over the feed-tray.
9: Something such as a piece of brass or dirt under one of the belt-catch feed-levers in the top-cover.
10: I would also check the operation of the receiver-cams vs. the condition of the bolt-rollers.
11: You can check for "dragging" and or binding of some parts by removing the recoil-spring and hand-operate the weapon. I do not believe that the barrel-jacket is belt....but was a proplem for some early MG34s.

Last, would be to give some feed-back here on the Board so that I and others can learn more about the MG34.

Regards, RichardS.
Blanksguy2001@chartermi.net

[JBaum]

When the gun is running away isn't the time to have to think about it, but to stop a runaway,

#1 - twist the belt so it can't feed.

#2 - pop the top cover open. It can't feed then, either. It's easy, it's fast, and above all, remember that the belt only goes on for a short time, so if nothing else,

#3 - keep the gun pointed downrange until it just runs out of cartridges if necessary.

[Blanksguy]

I believe that the man is asking for causes of the run-away-MG34, and ideas on what to look for as far as possible repairs.........not "immediate-action-drills".........but who knows, maybe he will let us know ?

Also....while we are on immediate-action-drills.....isn't #1: Maintain a firm hold of the weapon and insure/keep the weapon pointed in a safe direction ? .....and then to do the other procedures?

Regards, RichardS.
Blanksguy2001@chartermi.net

[JBaum]

I believe the guy is asking about runaways, not information about general repairs and maintenance.

However, my message starts with "to stop a runaway...".

How does "Maintain a firm hold of the weapon and insure/keep the weapon pointed in a safe direction" stop a runaway?

I think that my previous message is properly worded as stated, but if you'd like to write a message about "What to do if a runaway happens" or "Immediate Action Drill", then I think you should write one and not try to pick holes in a message that does not apply to your topic..

My message wasn't intended as a direct answer to his question (obviously). It was intended as general information that few people think about till after they have a runaway gun, then wish they'd have thought about it ahead of time.
It is accurate as stated, but apparently not stated to your liking.

You pretty well covered possible causes of a runaway in your message NOT. At least the information I gave was related to the initial question.

To specifically reply only to the request for information regarding causes of runaways, I'd say try the gun with another bolt, then check the trigger pack. Those two things are the most likely causes of a runaway. If the bolt change stops the runaway, inspect each part of the bolt till you find the cause. The firing pin lever or incorrect assembly are likely suspects. Wear on the sear in the trigger pack would be a possible cause of a problem, unless it's an eary trigger assembly with the gears and rate reducer. That's entirely another message.

[Blanksguy]

jbaum,

Just trying to be helpful with information to help the man with a problem MG34. I have owned/fire several from my collection over the years .

Why don't we ask him ("URAR104") what information he is looking for to clear all of this up and to help him better with his quest for information (?)........agreed ?

Regards, RichardS.
Blanksguy2001@chartermi.net

[drooling idiot]

wow , guys actually fighting to see who can be more helpful ..... you don't see that on just any forum

[Karbinator]

URAR,
Here's a snip from Folkes Universal MG "bible"......................................

NEW TRICKS FROM AN OLD DOG.............. Page 383

The Runaway gun
A runaway gun can be a very disturbing experiance for a novice. When this occurs with an MG34, don't panic. You have 2 choices: either let it keep on firing in a safe direction (you wouldn't fire it unless the direction was safe, would you?) until the belt is exhausted, or stop it by twisting the belt with your left hand (here your assistant can actually be of some help and twist the belt for you).

Try a spare bolt. If this doesn't help, the fault is Further inside the gun, and you may not be able to fix it on the spot.

The common causes for this ailment are a worn or broken sear, or sear bent, a weak sear spring, or a distorted safety. The mg34 safety is really nothing more than a big nuisance, and will sometimes cause the sear to stick. Another cause could be dirt and grime inside the trigger mechanism.

Sometimes non-experianced gunners will complain that their gun will only fire semi-automatically. There could well be technical reasons for this, but in the my experiance this is occasionaly caused by the gunner slightly relaxing his pressure on the trigger.

[URAR1004]

Thanks for all the feedback! We started using Yugo 50's to empty the belts and then started to use good 78' Portuguese 8mm. When it started running away we just held on on laughed, the owner didn't even really care, he just said "we want to shoot Full auto right!" I was going to go back out shooting with him in the afternoon take it apart and clean, but couldn't make it, he shoot 3k more rounds with it running away and didn't mind. I'll let you know what I find out when I take the bolt apart and clean the gun. Check out the mount that came with the gun, it pimped out!!!! He was embarrassed to bring it to the range, I wonder why? Does anyone know where to get parts to restore this tripod? I hope everyone is having a great Christmas Season. It’s starting to get cold here in Arizona.

[URAR1004]

How do you take the bolt apart? And what's the part called that stops the bolt when you let up on the trigger, it's in the trigger housing? jbaum I told my friend about your mg-34 manual he said he'll get one. Thanks for any help.

[JBaum]

If he's a real MG34 nut, the 1942 Butz manual is the way to go. I do have a couple other manuals for it though. Details are on my website, so I'll not waste the space here. The Butz manual, 1t 212 pages, is expensive because I spent 5 months on it to translate, but I've been told many times it's worth it.

thanks,

[URAR1004]

How do you take the bolt apart? And what's the part called that stops the bolt when you let up on the trigger, it's in the trigger housing? Thanks for any help I wanted to test it this weekend! Thanks

[URAR1004]

How do you take the bolt apart? And what's the part called that stops the bolt when you let up on the trigger, it's in the trigger housing? Thanks for any help I wanted to test it this weekend! Thanks

Is there anyone that can help, taking it out Saturday Morning. Thanks

[URAR1004]

Got the Bolt apart and received the Manuals from Jbaum and received a new bolt form OOW, the gun is still running away, gun is very clean, I'm using 78' Portuguese 8mm. When I look down into the receiver the part that catches the bolt (sear?) what's it called it looks very shiny and round. and will any of the parts in this picture do me any good as spares? or help fix the run away?? Thanks for your help!!!!

[TactAdv]

Got the Bolt apart and received the Manuals from Jbaum and received a new bolt form OOW, the gun is still running away, gun is very clean, I'm using 78' Portuguese 8mm. When I look down into the receiver the part that catches the bolt (sear?) what's it called it looks very shiny and round. and will any of the parts in this picture do me any good as spares? or help fix the run away?? Thanks for your help!!!!

----------------------------


'Couple of salient points for you........

1. No, none of the parts in that picture will do YOU any good......because *I* bought them all!! ;-)

2. If the gun stops AT ANY POINT by commanded action, i.e., you can command the gun to cease by proper trigger action, you have narrowed the possibilites down considerably. At that point....It is most likely a case of two opposite problems....either INSUFFICIENT recoil impulse, as someone else suggested, or EXCESSIVE recoil impulse.

-In the first case, you may be experiencing a recoil impulse insufficient to retain the bolt bent against the sear when commaned. This is normally an affect in the MG34 of useage of an improperly regulated booster cone aperture......check to be sure it is 11mm, and not larger than 11mm or the available energies will be greatly reduced. Over the years people have done all kinds of wicked-stupid sh*t to these guns for all manner of bizzarre reasons. On the opposite end of that spectrum be SURE it is not SMALLER than 11mm because if somehow there is a booster cone sized for 7.62NATO use (9mm) it will often not only cause a marked increase in ROF (bad, VERY bad), but the ability of the std buffer to absorb the extra recoil energies will be compromised and sometimes cause it to actually bounce off the sear bent as it moves FORWARD, basically overriding the sear.

-Secondly, the same effect can occur (increased recoil impulse) if the recouperator spring is badly worn, or God forbid, you have a weakened bolt latch spring. The recouperator going bad will only damage the gun, if the bolt latch weakens to the point of allowing the bolt to open under peak pressures, you can find the bolt carrier embedded in your forehead....or WORSE.
To check this......Firstly check the static retention force of the bolt latch by pulling on the charging handle as you would normally try and cock the gun, you should feel about 25-30 lbs of static restraint, then hear a very audible "SNAP!" sound as the bolt latch breaks cleanly, releasing the bolt and starting the unlocking movement. If the static restraint is easy to pull against....STOP USING THE GUN R.F.N. until you can have the latch spring properly replaced!!
Next, you need to verify that the recouperator is doing it's job of halting rearward movement of the BBL within the proper longitudinal relationship. With the receiver halves parted, insert a bare BBL into the receiver front section and with it locking into the bolt head, push BACKWARD slowly against the recouperator head feeling for resistance.....about 12-15 lbs of static resistance is acceptable. Again, if it pushes in too easily, have it replaced before firing the gun again.


If you are experincing TOTALLY uncommaned actions, runaways, your problem likely lies in the fact the trigger group is improperly allowing the sear ("trigger bar") to not function as needed. This is usually the result of weakened springs in one of two locations, either the sear spring ITSELF, or the safety lever retention spring.

BEFORE YOU DO ANY OF THE ABOVE, try exchanging the entire selector set FIRST, i.e., replace the selector lever and spring as an assembly. That usually fixes much of the problem as a bent safety lever, or damaged safety spring can jam the connector thereby jamming the sear function. Selectors are EASILY bent!!!

Good luck!
BTW.....your ugly-a*s tripod there, that's a converted BREN tripod, pretty common for '34 usage back in tihe early Eighties when they were el-cheapo.

-TomH