m53 failure to advance

[pongo1]

I'm a newby, just bought Wise Lite M53 and fired it for the first time yesterday. I used Romanian surplus ammo in it and results were mixed. Firstly, the gun is a major HOOT to shoot. The trigger pull is wonderful, especially compared to a 20+ lb MG34 semi trigger pull I experienced about 8 years back. On the negative side were several failures to advance a round after a chambered round was fired. Sometimes this happened after a single shot, sometimes after 15 or more shots. When the cover was raised there would be a round sitting on the feedplate, not advanced. A few times the bolt pushed the round into the edge of the chamber mouth and stuck. This usually would result in the belt link deforming. Sometimes the rounds were appeared not properly seated in the belts, and I'm not sure if this occurred In the feeding process or I maybe didn't properly check my belts beforehand! I did not lube the belts prior to use as they seemed lubed as I got them, but maybe I shold have. These problems were not resolved with supporting the belt, but were much improved with light traction on the fired end of the belt. Checking the gun over, the parts look very good with the exception of the barrel bushing. This part is quite corroded and has to be tapped with a mallet to be removed. Maybe this is the culprit? Any help/suggestions are greatly appreciated!

[drooling idiot]

sounds like you've got a pretty good grasp of what could be going wrong , especially for a .

I could see the barrel bearing eating into the recoil energy and maybe not leaving enough to cause the bolt to travel back as far as it should to advance the belt or strip and/or chamber a round if it did.

give the bearing a good cleaning with steel wool to smooth it up and then lube everything that moves.
try firing a bunch of loose rounds, then short belts to work the parts into each other. watch the process carefully for signs of where things are acting up.

look at replacing the bearing with a nice new one in the future.

[oakrodent]

Are the empties ejecting OK? If they are your bolt is cycling completely. Your top cover could be up alittle so the bolt roller is coming out of the feed guide. There is a few thing to look at if this is the problem. The best way to check this is to remove your trigger assy and bolt spring and push the bolt back and forth while watching everything from the bottom of the gun. Also is your feed try all the way down? If it is not it could cause your feed cover to bow alittle in the middle. I hope this helps.

[noonxnoon]

Oak,

Should the feed tray be completly flush to the receiver or is it 'normal' for the cover to lock but be up maybe an 1/8" or so?

[oakrodent]

The feed try has tabs on the bottom of it. These need to be down on the receiver. Hopefully it just takes adjusting the sides to correct this. More or likely it is hitting on the front inside radius of the receiver. Just behind the trunnion. This needs to be ground / machined to let the feed tray sit down correctly.

[Bil]

Make sure the bolt roller is seated in the lever that moves the feed pawl also. ---bil

[noonxnoon]

ack!

Not to piggieback off this thread...I meant 'top cover' closing flush or is 1/8" or so rise, OK.

The top cover locks, but it isn't flush...it has a slight rise.

[pongo1]

Feed tray is down. Bolt guide moves to the other side when bolt is retracted. I'll clean up/replace the barrel bushing and lube up the belts good.
I notice when I retract the cocking handle there is a loud THUNK after about 1/2" as a resistance is overcome. Is this normal? What casues it?
Thanks for your help!

[oakrodent]

That is normal. It is your rollers unlocking from the barrel. The barrel has to move rearward to unlock the bolt in the trunnion. Then your recoup will pop the barrel back forward. The bolt will snap to the rear much more easily after it has unlocked.

[drooling idiot]

ack!

Not to piggieback off this thread...I meant 'top cover' closing flush or is 1/8" or so rise, OK.

The top cover locks, but it isn't flush...it has a slight rise.

everyone I've worked on snapped tight when closed. you might be OK, but I'd be looking it over carefully before i fired the gun. much more in my comfort zone if the covers latched tight.

[Franz 1796]

Before you bother with a new barrel bushing, check the grooves in the receiver that the bushing travels in. On my M-53 I had the same problem and identified "mushrooming" at the end of the grooves as the problem (the grooves in the receiver, not the removable bushing). I called Wise Lite who recommended I send it back, or I could just use a Dremel to smooth out the bumps which is what they told me they would be doing. They told me this was normal and would only need to be done once. I did as they recommended and had a bit more mushrooming after the next range session, but not nearly as much as the first time. Did the same with the Dremel again, and did not have any trouble on the next range session.