[bigblock]

I have a MG34 semi on a TNW receiver and when I charge the gun the bolt slides real rough and is hard to pull back and sometimes sticks. After a few pulls the bolt makes a click sound and gets stuck and the charging handle pulls free of the bolt and wont grab It again. I have to take the butt stock off and force the bolt out of the receiver. there is a rod on the top of the bolt that I assume is the ejector. It slides through the top of the bolt into the face of the bolt at an angle. Is this supposed to have any spring tension? this one has no spring tension on It and slides back and fourth freely. Where It comes through the top of the bolt Its all buggered up and I think thats whats hitting the receiver and causing this problem. When I re install the bolt I have to push this "ejector" forward with my finger so It protrudes at its furthest point through the face of the bolt to get It to slide in the receiver. HEEEEElp me with my new toy please!!

 

[wetwilly]

Thats the ejector you're decribing, the plunger you have to push forward to get the bolt in. I have to do the same to get my bolt past the ejector plate. The only 2 ejectors I've ever seen were pretty beat but worked ok. These rifles need lubed well. TNW recommends TW 25 or something like that. I've seen it on Brownells websight or TNW will sell you some. If you feel lube is not an issue, open the top cover, pull off the feed tray, take a piece of wood and lay crossways in front of the protrusion on the bolt carrier that works the belt feed mechanism and see if you can pull the bolt back easily. Do not use the charging handle, leave it in the forward position. If it's hard to pull back, or feels like it's dragging, check the rivits that hold the cam plates to the reciever. Make sure the rollers on the bolt are there and turn freely. If it pulls back and goes forward with no noticable drag, the problem is probably wear on the pin that's attached to the charging handle. If this is worn or bent just a little bit, it will cause what you posted to happen. There are 2 things that the charging handle does. The most obvious is it pulls the bolt back. If the pin is worn it can act like a cam and shove the bolt to the side and cause it to bind. The other thing it does is harder to see and understand. On the bottom of the barrel shroud, right next to the pin that you push to remove the shroud from the reciever, is a sping loaded tab that looks like its only reason for being is to keep the charging handle locked forward during firing. This tab goes through the reciever and locks the bolt in place too. Take the bolt out, put the charging handle all the way forward until it engages the tab and you can see the bolt lock move. If the pin that pulls the bolt back is worn, it throws the timing off on that locking tab and makes it a bear to pull back. Good luck on your new toy.

 

[bigblock]

The pin on the charging handle is pretty beat up looking I think from this problem. When I put the charging handle locked in the forward position and use a piece of wood to pull the bolt back Its hard to do and the bolt itself seems to not want to twist and move and It seems to "half lock" between being cocked and not cocked. Everything is well lubed with lithium grease right now and I dont see anything interfering with the rollers on the bolt. I tried to find a tutorial on taking the bolt apart but I cant find one. Ive gotten as far as twisting the bolt to disengage the fireing pin but on the back of the bolt It doesn't look like any other bolts Ive found in pictures so I cant figure out how to take It apart. Even when I pull the bolt back as far as it will go with the wood and let It slam forward Its still in that half cocked mode and sometimes I can bang It forward with the wood and sometimes Its just stuck. This really sucks! I paid a crapload of money for this thing.

 

[www.Prussia.us]

That is some good advice WetWilly, I wish YouTube had videos of people like yourself troubleshoting the '34, now that would be helpful.

 

[wetwilly]

If the bolt does not retract easy using the wood trick, I would focus on the cam area. Wish I could post some pics. Check out these 2 places. There have been many dicussions and troubleshooting on them. I would never have gotten mine built without them and all the helpful folks pitching in. There are some good pics on the mg42 sight in the mg 34 section that show the cams and the rivits that have caused the same troubles you have had. If the pin on the charging handle is worn you will need to replace it or build it up with weld and shape it like I did. I spent many hours polishing the cams AND the bolt trying to get mine to cycle smoothly before I found the real problem. Do you know if this was built by TNW or homebuilt using one of their recievers?
http://www.weaponeer.net/forum/forum_topics.asp?FID=424&PN=1
http://www.mg42.us/

 

[wetwilly]

Pull the trigger assembly off and try moving the bolt. The bolt could be hanging up or dragging on the trigger.

 

[bigblock]

Ok, the new charging handle assembly is in the way and I Finlay see the rivets holding the cams in place. they are slightly raised and look like they have wear on them. I got the dremmel tool out to polish them so say a prayer for me!

 

[wetwilly]

I used a dremel with some of the "flapper" type tools. Then used a polishing tip. Go slow and check often.

 

[bigblock]

Alright. I polished as much as I feel comfortable for now as my pin on my charging handle Is totally wasted. Its hard to tell how hard It pulls with a wood stick. I ordered a charging handle from numrich and I hope its in better shape than mine. I received the gun in Its major pcs. and the guy who shipped It left the bolt in the receiver. When I got It home the bolt was jammed in limbo with the charger handle pin. I was forced after lots of prying and pushing with my fingers to tap It with a small plastic hammer which freed It from the pin but totally chunked It. Now for another bolt question. My bolt is different than all the ones I see in pictures. Theres some guy on youtube that shows how to disassemble It but the jackass goes too fast. the first difference is I dont have that flap on the back to release the back of the bolt. Mine has two knurled button's I have to push together, lift up and then screw the back off. in the video he takes the back pc. of the bolt turns It around and uses the carrier to release the firing pin. that doesnt work with mine as It has a small wire lock ring holding It so I cant push It in to release that "J" shaped release mechanism. Am I supposed to take off that small lock ring? By the way wetwillie, I appreciate all the help. Im surprised your helping me after are disagreeing on another thread and I was a major smart ass! I guess you can at least agree with me when I say with all our differences we are all friends!

 

[wetwilly]

By the way wetwillie, I appreciate all the help. Im surprised your helping me after are disagreeing on another thread and I was a major smart ass! I guess you can at least agree with me when I say with all our differences we are all friends!

You're still a smart ass, by my god man this is an ailing belt fed we're talking about. What kind of a guy would let personal feelings get in the way of helping out in this situation?

 

[wetwilly]

http://www.projectguns.com/mg343.html
This is a link to Pirates tutorial on the TNW bolt conversion. He's got some very cool stuff posted there. I think it shows the same bolt end piece you describe. I think it's called a trigger gate. You need to remove the wire clip that holds the sear collar on to disassmble the bolt. After the sear collar is removed (don't lose this, they are $35+ to replace) I shove the back of the firing pin into a hole just big enough for the threaded part to fit in and the sleeve to rest on. Then you push down and twist. Remember that it's under spring tension so don't just let it go. I have used a vice with the jaws open just enough to allow the firing pin in but found that a hole in a piece of wood worked best because it helped grab the sleeve just enough to let me twist the bolt. This process is not fun and I would avoid it if possible but it is good experience and helps to understand how it all works together.

 

[bigblock]

Im getting very frustrated!! I bought the new charging handle from numrich and the gun Is still doing the same thing. The one that came with the gun, the pin that pulls the bolt back was mangled and the one from numrich was not as bad but still a little buggered. Im going to have a local guy weld a big nub on the end of the original one and I will re-shape It. First question, Is that pin round or does It have a slight bevel on the top of It?
Second question, I polished the rivets that hold the cams in flush but I hear what sounds to be the barrel clunk as I pull the bolt back just a tad bit. Is this normal? are the bolt rollers hanging up between the barrel reliefs and the cams? Last question, obviously It takes alot of force to pull the bolt back the first fraction of an inch. enough to make the pin on the charging handle deflect and pass It up. Also when I do get It pulled all the way back and let It go the bolt sometimes doesn't want to go all the way forward and lock up. So Is It possible the problem Is In the bolt? It slides in the receiver easily even with the trigger assembly in. Also there are three parts of the bolt TNW sells to fix the infamous hard trigger pull problem which Are not in my bolt as we speak. ( I dont know the names of the three parts as I have them written down at work) Could those parts fix the problem? Wetwilly, If you talk me through this and help me get this thing going, I swear I will never be a smart-ass again when we disagree in a thread!

 

[oprod]

Im getting very frustrated!! I bought the new charging handle from numrich and the gun Is still doing the same thing. Ya the semi charging handles have been modified so it cannot go in full auto.I suggest working with the old handle.The one that came with the gun, the pin that pulls the bolt back was mangled and the one from numrich was not as bad but still a little buggered. Im going to have a local guy weld a big nub on the end of the original one and I will re-shape It.Suggest you get the old one working first then make the new one a second spare. this is kinda a part that is gonna go out on you. First question, Is that pin round or does It have a slight bevel on the top of It?My pins were beveled inwards, no difference for function
Second question, I polished the rivets that hold the cams in flush but I hear what sounds to be the barrel clunk as I pull the bolt back just a tad bit. That is probably the sound of the barrel moving backwards this is normal Is this normal? are the bolt rollers hanging up between the barrel reliefs and the cams? i dont think soLast question, obviously It takes alot of force to pull the bolt back the first fraction of an inch. yes mine doenough to make the pin on the charging handle deflect and pass It up. the angle and width of thepiece of metal welded onto your bolt and the length and width of the anle of the "L" catching the piece welded onto the bolt are probably not corectly aligned and is causing it to slip off. try a hammer to the bolt piece and moving it 1/16 or so over and see if it temporarily fixes your problem(until it bends over again) Also when I do get It pulled all the way back and let It go the bolt sometimes doesn't want to go all the way forward and lock up.check to stud on top of the bolt interfering with back top end of reciever. should slide past ealily. check for interference with the piece welded onto the bolt that the charging handle uses, it could be interfering with a piece of the spring unit that pushes the barrel forward interference would be near trigger area. Also check clearance issues with side of hammer and the bolt.( again that welded on piece) Also check for interference with the extension weled on to the back of the bolt. sometimes these are welded on a little crooked and cause the bolt to drag. So Is It possible the problem Is In the bolt? It slides in the receiver easily even with the trigger assembly in.is problem only after hammer has tripped? Also there are three parts of the bolt TNW sells to fix the infamous hard trigger pull problem which Are not in my bolt as we speak. ( I dont know the names of the three parts as I have them written down at work) Could those parts fix the problem? Wetwilly, If you talk me through this and help me get this thing going, I swear I will never be a smart-ass again when we disagree in a thread!Even I have read your rants and am contantly amazed at your thoughtful-lessness!

__________________

 

[oprod]

More thoughts

Try taking your flashhider and booster off. turn gun on its barrel and see if gun bounces enough to unlock itself... it should. if it does not you have a tweak in the forend somewhere. look at the muzzle end first for problems then mess around in the rear locking area. I had a weld in the reciever that was ever so slightly interfering with the barrel movement only when the gun was fully assembled. took a while to figgure that one out. this is a complicated system and you need to spend a little more time looking at how the modified system works in conjunction with other parts ie the locking mechenism, the barrel tensioning spring, the force to turn the bolt, and at what point does it begin to turn in relationship to the position of the barrel in the reciever. Spend more time on mg42.us to look for answers. and be kind to those on the boards.

 

[bigblock]

Thanks for all the advice oprod. I will look at all these things tomorrow and let you know. I didn't know there was any difference between the charging handles, being full or semi auto. The bolt not going into full lockup is when I pull the bolt back all the way with a flat piece of wood and let It slam forward so I dont know if the bolt is cocked or not. (still getting familiar with new toy) I love ya for all the advice but hate your pink font burning my eyes! ( hey, If Im going to have a rep as a ranter, I dont want to jeopardize It by being nice) thanks again and will keep you informed.

 

[oprod]

bolt not going into full lock up

bolt not going into full lock up.
1.the springs on these guns are normally cut down to about 13-14 coils as i remember. this of course reduces bolts required energy so the gun is touchy and everything needs to work without interferance issues.
2. remove your trigger froup and your oprod and see if it works correctly.
3. install each of the above one at a time to check for interferance.
4. lock up is pretty serious so you will find having the booster off and unlocking the bolt by placing barrrel on floor and pushing reciever down works well.

 

[bigblock]

Thanks again for all the advise. i haven't had a chance to mess with It today as I had a long work day and the little woman just got home and needs some attention. Im printing out all this stuff and Will hopefully have a session with It tomorrow. When you say remove the trigger group and the op rod, which piece is the op rod?
thanks again!

 

[oprod]

duh my part

oops not oprod rather charging handle. my biff

 

[bigblock]

OK I hope I made a huge breakthrough or possibly not. I tried everything oprod suggested and I still cant see any interference with the bolt to receiver. I tried taking off the trigger group and the charging handle. and still too hard to pull back. I had the pin on the charging handle welded up but am just now starting to file It to shape. The (hopefully) breakthrough I had was pulling the bolt back with the piece of wood is hard the first time, then If I dont dry fire the gun It pulls back nice and easy and when let go under the main spring pressure and butt stock installed It locks up every time. I could do this a million times with the same results but when I dry fire the gun the first pull Is real hard again. Im guessing the bolt is cocking itself on the initial starting of the pull back. Did I get anywhere? could the spring in the bolt be too stiff? If I take the bolt out and trip the trigger by pushing the lever and twisting It It Is real hard to twist It back with my hands.

 

[bigblock]

OK I shaped the weld glob on the pin of the charging handle perfect. First I install the charging handle and lock It in Its forward position. Then I put the bolt in the receiver and throw It forward into complete lockup. Then install the main spring and the butt plate. I can charge this thing Until Im blue in the face with no interference and It locks up every time when I let go and let It slam forward. Then If I dry fire the gun, pull back and the resistance is hard again and I can feel the pin wanting to deflect off the bolt. what the hell?