FirearmsEnthusiast
CGN frequent flyer
- Location
- Kingston, ON
That’s great!
As Deathrawt pointed out, be sure to loosen the tiny setscrew on the front sight before attempting to adjust...it’s easy to miss!
The MG34 Repair and Troubleshooting Thread
- Thread starter DILLIGAF
- Start date
That’s great!
As Deathrawt pointed out, be sure to loosen the tiny setscrew on the front sight before attempting to adjust...it’s easy to miss!
FirearmsEnthusiast
CGN frequent flyer
- Location
- Kingston, ON
All of the TNW MG34s are a mix of new and old parts. The rumour is that there is minimal testing before they leave TNW, and warranty service is a nightmare in Canada (moreso now with new ITAR restrictions on belt-fed exports after July 1), so you should be prepared to maintain the gun yourself. If you ever feel like a run from the GTA to Kingston (2.5 hours east), we could shoot your MG34 (and my MG34) and before we do that, we would make sure that the gun is properly initialized - primarily ensuring proper bolt lubrication and lubrication of the 2 rollers on the trigger bar (need to remove the trigger housing to see these). Also ensure that the 2 bolt rollers on the bolt rotate freely (like an M14 / M1A). I bought my MG34 used on CGN and while the owner advertised it as "running perfectly", it arrived with the bolt stuck forward and a bolt roller missing, and a trigger bar roller seized from no lube.
Don't assume you can just head out to the range with a zillion 8mm Mauser rounds and start blasting away - maybe you can, but maybe something will break.
8mm Mauser is expensive as factory ammo, but is easy to handload for. Another alternartive is to buy a .308 conversion kit from IRunGuns or from BRP Guns in Georgia directly. I got mine through IRG and it's awesome. A one-time replacement of one of the feed pawl parts in the top cover, an (optional I feel) installation of a spacer in the feed tray (I didn't do this and mine feeds fine), and a 10 second barrel change and you can swap between 8mm and .308.
These are awesome guns when you get them running properly, and it's worth investing some time to learn how they work and how TNW modified the bolt and sear assembly to allow to fire semi-auto from closed bolt. This thread also contains lots of good advice.
Feel free to PM me if you want to meet up in September in sunny Kingston.
- Location
- The Kawartha Lakes Region in Ontario
Awesome! Please post us some pics when you can, these guns are always a treat to view!
There is alot of good info in this thread.
I'm no expert, but in addition to what FirearmsEnthusiast said, installing an original firing spring is a good idea.
Be prepared to stock up on spare parts.
That and having a lot of patience.
I'm no expert, but in addition to what FirearmsEnthusiast said, installing an original firing spring is a good idea.
Be prepared to stock up on spare parts.
That and having a lot of patience.
FirearmsEnthusiast
CGN frequent flyer
- Location
- Kingston, ON
Yes - a German firing pin spring significantly reduces cycling force and trigger pull force.
Also, order some TW25B lubricant tubes - the TNW recommenced lubricant - got mine at Amazon.
They are actually getting worse as time goes on, Just go check out the MG34 forum and FB page. C0st me 800$ to get mine running properly. Pretty much replace every single TNW part with original ones.
Are you thinking about the "Butz" manual?
A guy name John Baum has made translations of piles of MG34 and MG42 manuals and others, including a translation of the "Butz" manual.
"M.G. 34 Butz Manual"
https://www.germanmanuals.com/manuals.html
He also runs a website MG42.us, however, the site recently crashed, and he is working to recover it or start fresh.
FirearmsEnthusiast
CGN frequent flyer
- Location
- Kingston, ON
The Butz manual is cool and worth picking up a copy...however it’s a translation of the original WW II manual for the MG34. As such, it does cover some of the failure modes (jams, failure to cycle) but not the issues directly related to the TNW semi-auto conversion. This thread, plus some US forums do a better job discussing these issues.
For “gunna has” - if you post some more information as to the problems you’re having, we might be able to help you.
For the hard trigger pull, substituting an original German firing pin spring in the bolt for the crazy-strong TNW spring really improves trigger pull weight and reduces cycling effort. The TNW spring is only really necessary for shooting milsurp 8mm with hard/old military primers...which I avoid as some of these loads are pretty hot anyway. Factory 8mm ammo is easily ignited with the German firing pin spring.
As for the jamming issue - is the gun ejecting the fired casing OK? Does the jam occur when feeding the next round? Is the next round getting hung up on the feed tray? This is common and can be fixed easily. Tell us more about how the jam happens and we can help...
FirearmsEnthusiast
CGN frequent flyer
- Location
- Kingston, ON
There is no troubleshooting manual for the MG34 (though I am tempted to put my notes together and publish one!)
This is often caused by one of several factors - let's go through the list.
1. Improper charging: 2 methods work for the TNW:
Method 1: lock the bolt back by pulling bolt all the way back, engaging safety lever, then EASING the bolt forward onto the safety (letting it fly can jam it against the safety). Then put a belt into the feed tray with an empty link over the belt. Close the top cover. If it doesn't latch, switch the position of the feed arm located under the top cover. Relieve the tension on the safety, disengage it, and let bolt go forward. There will be no round in the chamber yet. Then pull the bolt all the way back and let it fly forward. This should charge the gun and position the belt to feed properly on subsequent rounds.
Method 2: start with bolt forward on an empty chamber. Put the belt into the feed tray with an empty link over the bolt, and first live round in the next link to the left. Close top cover. Pull the bolt back and let fly. Then pull bolt back and let fly a second time - this will chamber the first round. Should cycle after that.
I would load 5 rounds max on the belt until the gun is stable. If it goes full auto, you may have to twist the belt to stop it. This is very rare on the TNW MG34 and is a malfunction.
2. Non-lubricated belts - lubricate the inside of each belt link with machine oil to allow the round to be stripped without losing all forward momentum of the bolt. German units often used paraffin wax for lubrication and to store loaded belts.
3. Loose flash hider: flash hider should be finder tight and one of the machined grooves should engage the "retainer hook". A loose flash hider inhibits recoil impulse and short-cycles the gun.
4. Booster cone - check for excessive carbon buildup on the booster cone assembly and on the ridges at the end of the barrel. Also, measure the diameter of the hole in the booster cone. TNW is notorious for using very tight cones that trap excess gas and put additional stress on the action during cycling. I like a 10 or 11mm cone, but have seen several 9mm diameter cones.
5. Misaligned top cover. If the gun has been charged properly and doesn't feed the second round, place a thin (0.5-1cm) piece of wood on top of the rear sight and push the top cover all the way up to rest on the wood. Then gently push the far end of the top cover down a few times using the wood as a fulcrum. This will bend the top cover hinge a tiny bit, making it more flush with with the feed tray. Manually cycle a few dummy rounds on a belt to confirm good cycling.
TNW has also recommended machining a wider slot for the round in the feed tray - I prefer not doing this - let's get the gun working as originally designed.
Please check these items and report back. Hope this helps!
Very good info above.
FirearmsEnthusiast
CGN frequent flyer
- Location
- Kingston, ON
Here are some photos to support one of the steps I outlined above:
5. Misaligned top cover. If the gun has been charged properly and doesn't feed the second round, place a thin (0.5-1cm) piece of wood on top of the rear sight and push the top cover all the way up to rest on the wood. Then gently push the far end of the top cover down a few times using the wood as a fulcrum. This will bend the top cover hinge a tiny bit, making it more flush with with the feed tray. Manually cycle a few dummy rounds on a belt to confirm good cycling.
The jam happens when the bolt advances under the cartridge causing a jam about 1/2 way into the chamber.
This is due to the cartridge not being held by the pawls on the feed tray at the correct angle, so the top cover feed assembly needs to be aligned so it's parallel to the feed tray.
Here's a shot with the wood strip in place. Then push the far (unsupported) end of the feed tray gently down towards the barrel. Do this a few times and fire 2-3 rounds to confirm function.
Hope this helps. Let us know if this looks like the jam you are experiencing.
5. Misaligned top cover. If the gun has been charged properly and doesn't feed the second round, place a thin (0.5-1cm) piece of wood on top of the rear sight and push the top cover all the way up to rest on the wood. Then gently push the far end of the top cover down a few times using the wood as a fulcrum. This will bend the top cover hinge a tiny bit, making it more flush with with the feed tray. Manually cycle a few dummy rounds on a belt to confirm good cycling.
The jam happens when the bolt advances under the cartridge causing a jam about 1/2 way into the chamber.
This is due to the cartridge not being held by the pawls on the feed tray at the correct angle, so the top cover feed assembly needs to be aligned so it's parallel to the feed tray.
Here's a shot with the wood strip in place. Then push the far (unsupported) end of the feed tray gently down towards the barrel. Do this a few times and fire 2-3 rounds to confirm function.
Hope this helps. Let us know if this looks like the jam you are experiencing.
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fingers284
CGN Ultra frequent flyer
- Location
- Alberta Cowboy Ranges
Just read this and although it is a good idea for feeding rounds continuously...and I'm not disputing the fact that it is needed for reliable feeding but have to wonder if this is the cause of most of the rollers being destroyed that are mentioned much earlier in this thread.
If you oil the links then the case also has oil on it when it is chambered. Hand loading manuals & gun manufacturers, for years, have all cautioned against using ammo that the case lube/oil has not been thoroughly cleaned off...the claim being that cases with lube on them do not "grip" the chamber walls and control bolt face pressure the way they were designed too , consequently much more pressure is allowed to be forced onto the bolt. Constantly using lube on the cases used in your guns would allow every round to hammer the bolt back much harder than the rollers manufactured in North America were engineered/designed to handle. From reading this thread I have garnered that the "original" German manuf. rollers last a long time...the German manufacturers probably identified this early on when the wax links were required.
I don't own one of theses guns so don't have any "first hand" experience at all, just an observation from an interested old shooter.
