Modification of a Standard Upper to .22

[John Sabato]

This thread will provide some insight of the amount of work involved in making permanent modifications to a Luger upper to convert it to .22 Long Rifle caliber.

This is not a project for the faint of heart, or for people whose engineering knowledge is challenged. This is a permanent alteration of a Luger with virtually no return to the original configuration.

This type of major modification should only be done on mismatched parts Lugers.

This thread was inspired by an upper assembly that was originally purchased by Ed Tinker some time ago in the condition in which it is presented in these photos, and hopefully with time, it will include the continued attempt to make this one of a kind assembly a completed project.

Here are the photos that Ed posted in this thread...

http://forum.lugerforum.com/showthre...threadid=18722








My thanks to Ed Tinker for sending me this upper for this study.


...more to come... stay tuned.

[John Sabato]

Here are the first 8 images of this .22 conversion attempt from an unknown gunsmith. Take particular note of all the steel that has been removed by drilling and milling to lighten the toggle train for movement by a .22 caliber rimfire... It is assumed at this point that the addition of a properly chambered and headspaced barrel, and a standard .22 conversion magazine that this upper would function correctly... Someday I hope to find out. Comments and suggestions are welcome.

[John Sabato]

Eight more images of this modification...

















More to come...

[John Sabato]

Here is the next installment...

















Still more images soon, stay tuned for additons.

[John Sabato]

The final installment of images of this conversion. If anyone wants other views of this work, just leave a post here and I will take them as soon as I have time.



Note that this upper receiver has NO provision for the standard Luger ejector... which leads me to believe that the upper reciever MAY have been produced from scratch to fit a standard Luger grip frame. It fits perfectly.







Open discussion on this modification work along with recommendations about the steps to finish this mod are welcomed.

[wlyon]

John

Interesting. What does the firing pin look like? It does look like a made from scratch,or at least much work on an existing. Appears to be quite old. If made from an original is there anything left to tell from what? It almost appears to be someones prototype? Thanks for sharing. Bill

[Edward Tinker]

well, I never looked at it this close John

Very interesting. The guy i bought it from, had bought it from a guy who had 'always" intended to make a 22 luger from it. I think he was a gunsmith and the guy I bought it from said he was a darn good one.


Ed

[John Sabato]

Bill,
Virtually all markings have been removed. The firing pin appears to be all custom work. I have not disassembled the breechblock yet. The firing pin spring guide and retainer is held in the block by a drift out pin.

[Jack Lawman]

On Wylon's conversion, the breechblock is relieved to accomodate a lengthened ejector:


On Ed's conversion, the ejector relief is on the bottom of the breechblock. Could an upper receiver mounted ejector be worked out in this configuration, or must it be mounted on the lower?


Jack

P.S. Sorry Ed, I like Wylon's better!

[John Sabato]

Hi Jack,

The more I study Ed's .22 conversion prototype pieces, the more intrigued I am about the design and the designer. Of course I agree that Bill Lyon's conversion has an edge since that conversion is finished and functioning (and we know it works!) and this one never was finished. I hope I can come up with the resources to finish this one.

This conversion may have been done one piece at a time. I am sure that there WAS a barrel made at some point, but it long ago was removed for whatever reason...maybe because it was incorrectly machined... who knows.

having mounted these piece in a Luger frame, I have determined that the work that has been done so far has not been without merit. It is pretty easy to operate the toggle by pushing on the bolt face with a cleaning rod, and I feel about the same resistance I would expect in a blowback .22 semi-auto pistol... and that is using the standard 9mm recoil spring. This means that the toggles never have to hit the ramps on the luger grip frame and the pistol would operate as a blowback... very similar in operation to the ERMA .22 conversions.

In answer to your question, could an upper receiver ejector be implemented in this conversion? I would have to answer "no" at this point.

There doesn't seem to be any way for an ejector to be mounted on the upper receiver and work from under the breechblock. It is my best engineering judgement that the original designer of this prototype was going to convert the orignial holdopen as the mounting point for the ejector, and abandon the use of the holdopen feature.

Possibly using a holdopen with an appropriate ejector shape mounted on the stop of the holdopen to ride the bottom of the bolt and kick the empty case straight up.

That problem could be what caused the development of this prototype to be abandoned... It is possible that the bolt face was designed and prototyped first without thinking of how ejection would be accomplished. A poor design in other words. Since the current configuration of the bolt face appears to have been copied from a simple bolt action rifle design and is using opposing extractors.

This method would provide a strong extraction method, but reliable ejection straight up may be a problem with the ejectors at the 3 and 9 o'clock position... I am sure that this is why Georg Luger and Hugo Borchardt put their ejector on the top of the bolt and kicked the empty out with an ejector that hit the bottom of the case.

The only way to know if this system is going to work is to first engineer a barrel that mates with the bolt, and then experiment with ejection being controlled from the holdopen.

I will need a section of .22 caliber barrel of appropriate diameter (about .60 inches or larger) to turn an appropriate barrel to fit in the threaded barrel stub that is already installed in receiver... if anyone has a scrap length of .22 rifle barrel of at least this diameter for me to experiment with, I would be a very willing recipient of the donation. Send me a PM if you or anyone may have an appropriate piece of .22 barrel you are willing to part with... It occurs to me, that a .22 Ruger Mark I or II barrel might be a good starting point. Someone may have one laying around that is left over from a rebarreling project... that would be great.

At the very least, a single shot conversion will be the result of this experiment. One the barrel has been turned, chambered and installed, with cuts for the dual extractors, then the next step will be experimenting with potential ejector designs...

After clearing the ejector design hurdle... the next step would be to kludge together a suitable magazine from an old standard Luger tube and maybe a section of a Ruger Mark I or II magazine inserted inside. I think this would be feeding at the appropriate angle to work with this bolt.

I would love to use a standard ERMA conversion magazine, but they are really expensive to buy for experimental purposes...

I invite questions on the design or these parts... and will post photos as progress is made...

[Jack Lawman]

Originally posted by John Sabato

That problem could be what caused the development of this prototype to be abandoned... It is possible that the bolt face was designed and prototyped first without thinking of how ejection would be accomplished. A poor design in other words. Since the current configuration of the bolt face appears to have been copied from a simple bolt action rifle design and is using opposing extractors.

That's what I was thinking... I wouldn't want to be in the shop when our designer had that "Holy C*#P" realization!

[Ron Wood]

With a double extractor, I think it would be very difficult to make an ejector since you would have to tear the spent case from under the extractors that are holding it on both sides rather than prying it out from under a single extractor.

[John Sabato]

Jack/Ron

I think it may be possible to modify the extractors by reducing their size. By modifying the bottom half of their tips so that their purchase on the cartridge case will be on the top half of the circumference thereby better encouraging straight up ejection by a blow from the ejector at the bottom center. I will carefully modify the extractor tips by shaping them to be smaller (Red areas of the extractors will be removed). Sorry about the crude image, but I don't have any image software where I am, only Microsoft Paint. I hope this image gives you a good understanding of my intended modification.



When I get a piece of .22 barrel to experiment with, the testing will begin in earnest.

[Jack Lawman]

I'd leave them alone for the first test, then try removing material from one side (in the manner you illustrated). The empty case should kick to the side of the full extractor (the smaller area extractor should let go of the rim first).

This whole breechblock thing is getting scary!

[John Sabato]

Very Funny Jack! it is even scarier in person.

[wlyon]

John
Went to a gunsmith friend of mine. I have 14" piece of a 22 rifle barrel. It is chambered and threaded on one end . Diameter inside the threads is .70+. Will send it to you if you can use it. This is an unfired piece of barrel. He takes them off and replaces with better barrels. It was on a CZ. It tapers down to .69. Bill

[John Sabato]

EXCELLENT Bill... please check your Private Messages... Thanks for your help.

[John Sabato]

These photos are of a .22 conversion owned by Patrick Villiers who lives in Germany. The .22 conversion parts are strictly Erma, but the target Bull barrel work looks like very custom work. These photos are located in the "Old Owner's Corner" that is left over from one of the first incarnations of the Luger forum before we came to this format, and created the Member's Gallery.






Photos Courtesy of Patrick Villiers

Here is Patrick's caption for his .22 Conversion:

I know that purists don�´t like Luger conversions and customizing, but the idea here is that it�´s proof that the idea is still alive. Georg Luger was working on variations until the time of his death. There are at least two people working on .22 Lugers here in Germany; Werle (see Waffen Werle - Links & Resources) and Johann Uhl. The simple idea is to use the Erma kit. A competition .22 Luger needs a heavy barrel. Mine was too heavy and has since had the sides milled off. The Erma conversion is not all that successful. It needs careful attention to the main spring (from a P 38) and the ammunition used.

[John Sabato]

Here is an update to this peculiar attempt to convert a standard Luger upper assembly to .22 Long Rifle.

As I continue to study the modifications made by the original engineering gunsmith for this .22 coversion attempt I am awed by his ingenuity... and left scratching my head by other things...

This image shows extensive modifications to the toggle to include a complete change to the design of the sear/striker/disconnector/toggle linkage:

Point D arrow is pointing at the new Sear/Striker. The sear engagement point is at Point A. The sear has been made an integral part of the breechblock. The firing pin release surface is completely different to match the new sear and the firing pin retainer is held in place by the pin at point B.

The new sear bar is pinned in place at point C and works much like the original sear does on the upper receiver.

The new disconnector shown at point H is identical in operation to the original sear/disconnector engineering except the whole operation has been moved to the breechblock.

Notice that the forward toggle cam is behind the new sear bar at Point G.

Point E and Point F show changes in the geometry of the toggle pin points to allow blowback of the breechblock without movement of the upper receiver. This is the reason for the new sear/disconnector. Without movement of the upper receiver the old sear/disconnector would never disconnect.

The original sear bar has been modified by replacing the spring loaded disconnector pin with a solid non moving pin that has a protrusion that passes the movement on to the new sear bar.

I will make more and better photos of this engineering and update this thread as I find time to disassemble the toggle further.

I still haven't quite figured out the purpose of the spring loaded pin behind the open toggle joint, as it does not engage anything. Perhaps it is a helper to opening the toggle on firing.

More to come as it happens. I hope all you armament engineering enthusiasts are enjoying this reverse engineering investigation thread.

[John Sabato]

Here are some new photos of additional parts showing just how extensive this modification prototype really is...

Bottom of the Upper Receivers...(conversion is on the top, bottom is 1937 S/42)



Bottom of the Chamber areas (conversion on the right)



Left Side Rear of the Upper Receiver (conversion on top) notice the roughness of the modifications on the sear / sear spring slot.



Right Side Rear of Upper Receiver (conversion on top) Notice the lack of the ejector opening.



All sides comparison of the sear bars (the conversion bar is on the bottom... dramatic and drastic changes here)






More images next post