i am thinking about making a 7.62x54r m53

[42rocker]

Richard
I wish that I could say all kinds of new stuff on this, but. I did talk with Troy (Oct 2014 Knob Creek) about how he was doing and he stated that he had been busy on other items.
UK59 belts seem to be what is talked about.
Hope some one has more to add.

Later 42rocker

[Blanksguy]

42rocker,
I've picked up a couple of the UK59-ammo-belts for trial during the R&D period of this......and have three (3) MG42 Bolt-Heads with the bolt-face machined to correct diameter for 7.62x54R rims.

I've also picked up 7.62x54R chamber-reamers for this project.

The next challenge seems to be "head-space" gauges. So far, the "industry" seems to see the 7.62x54R as a cartridge that head-spaces off of the cartridge-rim..........and not by how much room/space there is between the rear of the chambered-cartridge-rim and the bolt-face when the bolt-head is locked onto the barrel-extension.
I will continue to look for a source of full-length-type cartridge-case-type head=space-gauges.

If gauges cannot be found.......for my barrel I will try using SAAMI-Specs. for chambering..........or +.002" frr-space off the head of a know good cartridge-case (??).........or (??).
I'll also see if I can get some information from Bob-Naess reference using "used" 7.62x51mm/.308 barrels (like a well used MG3 barrel-assembly in .308).

I still have to look at:
1: Extractor-modification to retain "rim".
2: Top-Cover and Feed-Tray modifications for feeding.
3: The some other "adjustments" of parts at the first range event (Booster-Cup/"Nozzle", etc..).

Regards, RichardS
US Army, Retired
Blanksguy2001@outlook.com

[Blanksguy]

42rocker,
I now have a UK59 Belt-Loader in-bound so that I can load those UK59 ammo-belts. Remembering that these belts are loaded from the open side and not loaded from the rear like SG43/PKM-series belts, and feed forward. The MG42 crank-type Belt-Loader will not work.....and as the links have a small "L" shaped end-piece like some RPD-Belts (Note that the 7.62x54R is a "rimmed" cartridge), most belt-loaders that load from the rear of the Belt will not work (such as those for the Russian SG43/PKM-series belt=loaders.).

Next, I need to modify a couple of MG42 Extractors to be used in my modified MG42 Bolt-Heads.

If anyone can help out on this next request , I/we need a clear/enlarged photo of the inside of the top-cover/feed-tray from Folke's book on the German MG34 and MG42 as the earlier photo in this thread went "away". I've figured a couple different ways to make a "belt-stop" to stop the forward motion of the links as the bolt-head pushes the 7.62x54R cartridges forward to feed. Giving him credit for the photo (those are two books are a great references for anyone interested in the MG34 and/or MG42)......I'm figuring that the use of his photo from the Finish-museum will aid him in "sales" of his book, and for us in explaining the R&D portion of this conversion. Maybe see something else that I/we missed-??

In my search for more information, does anyone have an e-mail address to contact that Finish Museum that they can share with us (?)......or please contact them for a couple better photos of the underside of the top-cover and feed-tray for us.

Last, I don't recall who posted the photos of the 7.62x54R cartridges on the feed-tray, but if thos earlier photos could come-back and be posted here, it may help someone in helping us sort out all of the feeding issues and "adjustments".

Regards, RichardS
US Army, Retired
Blanksguy2001@outlook.com

[42rocker]

Good to see someone going forward on this. I'll try to get you a few things for this request over the next few days.

Later 42rocker

[Blanksguy]

42rocker,
Well my UK59 Belt-Loader arrived........and I did a little searching on the web for a couple photos of these UK59 (vz59) Belt-Loaders (my camera is temp. down), and of the belts that we are going to try using in our converted MG42.

"Kyle" over at vz59.blogspot.com did a short write up on these and one "issue" that they have when trying to load that last-link and/or "new" belts. He cautions against trying to load that last link (the connector-link) as they tended to bend inward on him.

As the photos below show, a very simple belt-loader to operate......and very few parts on the machine.
Regards, RichardS
US Army, Retired
Blanksguy2001@outlook.com

[42rocker]

Richard
Looks like an interesting loader. I'll get back with you later about some of this stuff, wife called Dinner Time.

Later 42rocker

[Blanksguy]

42rocker,
I am listing down the "POC" for the UK59 (vz59) Belt-Loaders here (not an ad) as these appear to only load the UK59/vz59 ammo-belts.

POC is Charles Erb
E-Mail address: charleserb@hotmail.com
He tells me that he only has about 25 of these Belt-Loaders left (in new or as-new condition).
I have not heard nor seen of any other importer of these Belt-Loaders so may want to send him an e-mail if you are planning to convert your MG42/M53/SA42 to 7.62x54R.

Charlie can send you photos of the belt-loaders in use, and there is a short "youtube" video of it loading 7.62x54R. Quick "search" of "UK59-Belt-Loader" on the web will bring it up in the listing.

Regards, RichardS
US Army, Retired
Blanksguy2001@outlook.com

[42rocker]

Thanks for sharing that. I'll keep trying to get out some of the info that you asked for after I do some more work on the house. Wife said something about Thanksgiving company on Saturday and so on.

Later 42rocker

[Blanksguy]

42rocker,
Posting three (3) MG42 Feed-Tray photos (8x57mm) to compare with the one from Folke's book when you get a chance to posted it (slightly enlarged) showing the inside of the top-cover and top of feed-tray of the converted MG42 in 7.62x54R.

In Folke's book photo, I believe that I can see a thin "spacer" at the inside front-left of the feed-tray (to keep cartridges/belt positioned to the rear of the feed-tray)......and maybe what looks like a re-positioning of the cartridge-stop on the right-side to a more forward position to allow room for the longer "links" used in their conversion to 7.62x54R (?).

Does anyone have a clear photo(s) of the left-side (feed-area of outside of gun) of that converted MG42 in Finland (?).........or other photos of the inside of the top-cover and feed-tray on the converted MG42 in Finland (?).

Regards, RichardS
US Army, Retired
Blanksguy2001@outlook.com

[42rocker]

Richard
Please do not convert that nice German feed tray. Convert a yugo please. Can offer trade and a few $ if needed.
I'll try to dig out Folke's book tonight and go from there.

Later 42rocker

[Blanksguy]

42rocker,
That MG42 8x57mm Feed-Tray is from an "auction-listing" (not one of mine), and is for reference and ideas/R&D only. I will be using a couple of 8x57mm M53 "Yugo" type-MG42 Feed-Trays for the R&D/modification-work.

One idea that I though about while looking at a newer-model M249 Feed-Tray is the cartridge "cut-out" in the center-forward where the cartridges (once starting their movement forward) are allowed to "drop-down" at the rear earlier than would happen with a normal MG42 Feed-Tray. (please see attached photo).
I understand (by looking at the photo in Folke's book) that this does not appear to have been done in the Finish conversion to 7.62x54R, but may be required for our conversion using the UK59/vz59 ammunition-belts.

At this point, these are just ideas/thoughts on making this work.

Regards, RichardS
US Army, Retired
Blanksguy2001@outlook.com

[Blanksguy]

42rocker,
.....and another photo of the UK59/vz59 Belt-Loader in use.

Regards, RichardS
US Army, Retired

[Blanksguy]

42rocker (or any MG42-Board member).
Does anyone have the ability to scan and post the two (2) photos from Folke's book, of the Finish conversion to 7.62x54R ????? ( 1: the inside of the Top-Cover/Feed-Tray and 2: The front of the modified Bolt-Face).

Question: Why the "Face" of the Bolt-Head has a horizontal slot cut into it (?).......What is the depth of this slot and how does it effect Feeding/Operation/and Ejection of cartridge-case after firing (?).

Regards, RichardS
US Army, Retired.

[Blanksguy]

Photos of the inside of the 7.62x54R converted Top-Cover/Feed-Tray, and of the 7.62x54R converted Bolt-Face (shown below). Both photos are from Folke's book "The German MG34 and MG42", which should be on the book-shelf of all MG42 Board-Members as a great source for information on both of these weapon-systems.

Regards, RichardS.
US Army, Retired

[Blanksguy]

........been a while on this subject (been moving State-so-State) so I thought I would check in to see if anyone has come up with additional photos and/or information on the Finish 7.62x54R conversion......or worked on their own project (?).

Regards, RichardS
US Army, Retired.

[amafrank]

I'm not sure why you don't understand the headspace gauge for a rimmed cartridge. It does measure the distance between the boltface and the case head with the bolt locked. The no-go guage will hopefully prevent the bolt from locking due to the inability to close completely. Headspace is the distance between the case head and the boltface when the bolt is locked. It doesn't matter whether the gauge itself measures from the shoulder to the boltface or from the breechface to the boltface. Regardless of which type you are using the procedure is the same: install the go gauge and insure the bolt closes and locks up completely. Next install the no-go gauge and insure the bolt does not close completely. With rimmed cartridges the gauge set has rim thickness that vary between the go and no-go by around .003" in the case of the 54R. With rimless cartridges the distance between the shoulder datum line and the case head will vary by around the same....in 308, 8mm etc. The result is always the same however so give it a shot.

Frank

[along]

The real question is would you want to shoot corrosive ammo out of it...

[Blanksguy]

amafrank,
Thank you for the posted information.

First.....remembering that MGs have a slightly looser chambering.....

The issue that I was having with Clymers 7.62x54R gauge was that "their" gauge was not only about 1" long.....but the "rim" was cut as a standard size rim thickness. When it was dropped into the unfinished chamber........it would bottom-out at the rim each time.
The was no bottle-neck area for the gauge to register against as (again) their gauge was only about 7/8" to 1" long (?). It would almost be like trying to headspace a 7.62x51mm/.308 Winchester with a gauge that looked like a .45ACP shell-case........

I talked with Clymer......and was told that they do not make a headspace gauge set for the 7.62x54R that would register off of the front of the bottle-neck of the cartridge.
Maybe they make them now (?).

Any suggestions on where to locate a set (?).

Regards, RichardS
US Army, Retired

[JBaum]

Full length headspace gauges for a rimmed cartridge do not exist. They won't exist next month, nor the month after that. Nobody makes them, and nobody will. It can't be done, it isn't done, and it wouldn't work if it was done, which is why they aren't made.

A rewording of what Frank is saying:

Rimless cartridges and rimmed cartridges are headspaced with two completely different methods to determine the same thing. Rimless cartridges are headspaced by the dimension from the shoulder (bottleneck) of the chamber to the bolt face. Rimmed cartridges are headspaced based on the dimension from the rear part of the rim, to the boltface, when the front part of the rim is against the chamber mouth.

Only rimless cartridges are headspaced from the chamber shoulder to the boltface, and to do that, you need a full length headspace gauge.

You won't find a shoulder-to-boltface/full length headspace gauge for a rimmed cartridge, because they're not headspaced with that dimension. They headspace with the dimension between the surface of the rim and the boltface, which has nothing to do with the internal dimensions of the chamber.

The headspace gauge for a rimmed cartridge only needs to be long enough to align itself in the chamber to make the rim sit correctly against the mouth of the chamber. It's only the rim that sits on top of the chamber that is actually used to check the headspace, because it is the rim of a rimmed cartridge that stops the cartridge from going any further into the chamber. A rimmed cartridge can not fall into the chamber past the rim, so any other dimension is irrelevant for head space purposes. With a rimless cartridge, the chamber shoulder is what stops it, so that is the front location for the start of the headspace dimension.

[amafrank]

Having chambered hundreds of 7.62X54R barrels I can tell you from experience that it doesn't matter where the shoulder is on the cartridge or the chamber as long as the rim is in the right place. Your headspace guages will only have about a half inch long spigot on the end of the rim because thats all you need. Its only there to keep the rim fairly centered and to keep it from rolling. You could use a flat disc of the correct thickness but it would be tough to hold in place. Rim thickness is the measurement. Your bolt and barrel have a fixed relationship set by the locking rollers and the location of the breechface.
Unscrew the barrel from the extension and put the bolt head in place til it locks up. Measure the distance from the forward flange of the extension to the face of the bolthead. Not the point where the bolt will hit the breechface but the part where the firing pin is. Now measure your go guage thickness. Subtract the thickness of the go guage from the distance measured. This is the distance from the breechface to the forward flange of the extension. You should also measure the depth of the pocket in the boltface. If its deeper than the go guage you'll need to take a bit off the front side of the bolt. You want the bolt to stop on the round not the breechface. This may be why you see a slot or mill marks on the bolt head in folkes book. The 42 typically has a deep pocket in the boltface and with the rimmed cartridge this can be a problem. It will stop the bolt before the face has contacted the rim of the case and excess play there can allow case head separations.
There is a lot of myth surrounding the idea that military chambers are bigger or headspaced differently than standard guages for civvie guns. Its not really true because there aren't such standards. In some cases the machinegun chambers have a different taper than bolt actions. This is true of the M2 Heavy barreled 50 BMG. Cases fired from these require more sizing work to fit the standard case guage. On the other hand the 54R chambers only real difference (and that of many other military MG chambers) is the depth. They are deeper to allow a bit more variation in shoulder locations. In 303 this is also the case. With the rimless rounds you can't do this though as headspace will be too large and case head separations are the result.
When you cut your chamber you can run the reamer in to the point where the shoulder on one particular type of ammo makes contact. Now run it in about 10 thou more. If you measure all the various makes of 54R ammo out there you'll find a variation of 20-30 thousandths in the location of the shoulder. For this reason you can make the chamber deeper than you would a 308 or 8mm. The cases don't headspace on the shoulder and if you cut it too short you won't allow the bolt to close on some ammo. The cases headspace on the rim so they don't keep the shoulder as a reference point and that means every manufacturer has his own idea of where it should be.
On the Vz59's we're building we can run any type of ammo out there because the chamber is deep enough to do so. Russian ammo is a bit short but bulgarian brass has a little crush to it when chambered. Its the way it has to be with this cartridge. If you are planning to reload for this rifle I'd suggest considering a different cal. Its possible but you won't get much life out of the brass. The 42 beats the crap out of necks anyway.

Hope something there helps
Frank