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M53 bushing replacement

Posted: Thu Mar 15, 2018 11:54 am
by Abominog
There are discussions about measuring the location of the bushing for replacement which leave me wondering "why"?

Forget about long vs. short bearing. For the sake of this discussion I'm talking about an M53 that was cut through the bushing and a replacement used Rhinemetall bushing from RTG.

If indeed one must measure to install the bushing, that would imply it's one of the last steps. Contrast that with the factory, which put the bushing in early in the production. Also, assuming that there was no equivilent of "headspace" for the bushing, they were all produced the same.

Ergo, if one can install a replacement M53 (!!) bushing in the same location as the old one, then there is no reason the repair cannot be implemented as step one, right?

Project Guns says "and the bushing set to the proper depth" without explaining what the proper depth is. But again, if one can get the replacement bushing in the same location (distance) then no problem, right?

The variable though may be a Rhinemetall bushing vs. M53 bushing. Maybe. I'm asking. Maybe they are the same. Thus, one could clean up the shroud to where the rear face of the bearing rests, and weld away.

Any input? I do ask we stay away from any inclusion of the MG3 bushing or bearing since that's already been discussed.


Re: M53 bushing replacement

Posted: Fri Mar 16, 2018 6:42 pm
by Blanksguy may have to include the MG3 Bushing as you will have to know what the replacement bushing was made for ........ correct (?)......used or new it was either made MG42/MG1/MG3/MG74/M53/?......but I believe that you will find that they will all allow you some latitude/adjustment in Bushing-location when you go to weld it in.

Project guns puts out a lot of great information.....and seems to be updating these as time goes by, and some of the "threads" on our Board cover the repair of this section as you have found out.

What you may be asking is "if it is okay to weld the busing as an earlier point during re-assembly"............and the only thing that I can tell you is "MAYBE". It will all depend on the lengths and locations of the receiver parts that you have as all of these "cuts" and assemblies are different.

An example of this is the location of that forward Bushing in the receiver. You have to be able to locate it correctly so that the Barrel-Bearing will fit and be oriented-correctly to install the Barrel-Assembly........but you also have to be able to allow the Barrel and Barrel-Bearing to move forward until the Barrel contacts the Barrel-Stop in the receiver. Then the Barrel-Assembly should be able to move to the rear during recoil without the "keys" on the Barrel-Bearing contacting the "key-ways" in the Bushing.....or they will get sheared-off. I believe that people should be more concerned with the location of the Cam-Pcs. and Barrel-Stop than they are with the Bushing at the front as this may change the timing of the "unlocking" of the bolt from the barrel-extension.

So I guess what I am saying here is to assembly your receiver to allow the cam-pcs. and Barrel-Assembly be correctly set up for operation against that Barrel-stop.........and then weld in your Busing at the front insuring that once the Barrel-Assembly is installed in the Barrel-Bearing......allowing for a very slight movement from that position for the Barrel-Bearing to move forward before the "keys" contact the inside-stops in the Bushing "if" the barrel was not installed.
Understand (?).

Regards, RichardS
US Army, RET

Re: M53 bushing replacement

Posted: Fri Mar 16, 2018 10:39 pm
by Abominog
Thanks Richard.

OK, I can readily tell the difference between MG42 and M3 barrel do I discern between bushings?

Re: M53 bushing replacement

Posted: Sat Mar 17, 2018 10:34 am
by Blanksguy
I have not seen enough of these Bushing (that I knew for certain were a specific make/model) to know the answer to your question............


You are building an SA42 or registered MG42/MG3/M53.......and unless you are looking for a specific "LOOK".........does it really matter (?). You really need to be more concerned with correct-operation of those moving parts (barrel-assembly and barrel-bearing0....... weld in the Bushing to insure that you can achieve correct movement/operation of those parts.........correct.

I guess I don't understand exactly what you are asking. Are you looking for a part-by-part bushing measurement chart with pictures of each Bushing (?)..........or someone to say "if you weld the Bushing on so that it sticks out __________" from the forward opening of the receiver on _______ side, you will be correct for location" (This isn't correct....and you may end up welding on the Forward-Receiver-Bushing either too far out or too far in for correct operation).(?)

Your receiver-build is "flexible" by nature and as such, you need to be more concerned with the location of the barrel-assembly and barrel-bearing for correct-operation/movement.........and then weld on the forward-Bushing.
A good example is the SA42 "Carbine" that was built and photos posted.....which I believe was by Project-Guns....and I'll see if I can locate a photo to post for him......

What are you trying to achieve/build (?).
What "LOOK" are you trying to achieve (?).

Regards, RichardS
US Army, RET

Re: M53 bushing replacement

Posted: Sat Mar 17, 2018 10:54 am
by Abominog
I was hoping to weld in the bushing on multiple shrouds for resale (and also my own semi M53).

In looking at the RTG ad again, it is quite clear that the used Rhinemetall bushings are MG3. So my original request to avoid MG3 in the discussion is void. Duh.

So with the M53 kit comes the MG42-style short bearing. I presume this will work fine with the RTG Rhinemetall MG3 bushing, with the length/distance being the element in question. I don't have an MG42 bushing on hand to compare- is there a difference between the MG42/ M53 and MG3 bushings?

Re: M53 bushing replacement

Posted: Sat Mar 17, 2018 5:14 pm
by Blanksguy
Difference (?).....Yes.

Your statement of just welding in Bushings on a few Barrel-Jackets for re-sale (?).............may not be a good their location may be off.

......if the Bushing is located too far rearward, the keys that keep the barrel-bearing oriented for installation and removal of the barrel will hit the key-way "stops" in the front of the might also have the issue of the distance needed between the barrel-stop riveted inside the receiver.......and those same stops at the front of the Bushing. ....and, isn't there a piece under the front-sight/Flash-Hider catch that catches the Barrel-Bearing so it doesn't fall out after barrel-assembly is removed (?).

So........if it were my SA42 receiver.........I would try to located the cam-pcs./receiver in relation to the Barrel-Stop first...............basically the same as starting with what WiseLite calls their "SA42-Receiver".....and build forward from the location of the forward Bushing last.
This would be slightly different when say, welding together a 3 or 4-cut MG42 receiver (remembering the "Block".......and why I say that each "build" is "flexible" and again "slightly different" in each case.

Again....each build is different.........and the receiver parts have some flexibility of location to some degree during your build.

For what you want to do, I guess that if your barrel-jackets already have a "good" barrel-stop installed......... and you use a standard length MG42/MG3 could locate the bushings and "weld-away" after insuring the Bushing is located correctly for the Barrel-Bearings that you will use.

Regards, RichardS
US Army, RET

Re: M53 bushing replacement

Posted: Sat Mar 24, 2018 8:00 am
by Abominog
I procured a M3 bushing from RTG. Combined with the M53 flash hider and recoil nozzle, the FH won't screw onto the M3 bushing all the way because the recoil nozzle prohibits it from doing so. It would appear that the M3 bushing threaded area is likely longer than that of the M53.

Re: M53 bushing replacement

Posted: Sat Mar 24, 2018 7:14 pm
by Blanksguy
To give you more information to add to your statement about those parts.........I need to ask if you had a question (?).

Otherwise........I would have to ask for a clear photo of those parts that you are talking about, laid out together to see what is going on.
I can make guesses........but that would only prolong the same request for clear-photos and/or information of exactly what you purchased from RTG Parts.
Only then can I, or anyone, assist you.

Currently, it sounds like the Yugo (M53) Flash-Hider......will only partially screw down onto the MG3 Receiver-Bushing until it makes contact with the Booster-Cup/"Nozzle". ....... and when these parts are assemble onto an MG42, this is correct. You see, the Booster-Cup/"Nozzle" is stopping the Flash-Hider from screwing down further.
But I believe that you original questions concern where to locate the Receiver-Bushing for welding of same (?).

Next question.......(?).
Regards, RichardS
US Army, RET

Re: M53 bushing replacement

Posted: Sat Mar 24, 2018 10:11 pm
by Abominog
I did somewhat change the subject, but it's still on topic since it involves all the same parts.

Yes, it appears that the MG3 bushing threaded section is longer than that of the M53. It does indeed bottom out on the booster cup/ nozzle.

I'm surprised nobody has complained about this before. I assume it's only cosmetic.

Re: M53 bushing replacement

Posted: Sun Mar 25, 2018 1:52 am
by shooter42
I would double check your booster threading, my MG-3 cut shroud has no issue with the either of my M53 boosters or my MG-3 booster.

Could you have the "OEM new" instead of "used" RTG reciever bushing? It says there may be addition machining required for the "OEM new" one.