Erma .22 coversion kit for 9mm P.08

[ithacaartist]

A recent auction purchase arrived the other day, a post war .22 conversion kit. The auction was a relatively small one, available online; the lot listing was a little obscure--I almost went by it without reading further, but had that "Hey, waaait a minute..." feeling about it and clicked to see the related pic. Bingo!

The box is the green cardboard variety, sound and fit. Its only detraction is the stained area inside the lid, where someone had Scotch-taped something, perhaps the instructions, now gone. The kit is comprised of the barrel liner with its nuts and spacer, the breech block/toggle assembly which takes the place of the P.08 breech block and toggle train, and the conversion mag. There is accommodation inside the box for, I think, the .22 cleaning rod, which is missing.

2 issues.

First, and the more annoying, it will not fit and function correctly. The slots milled into the inside lengths of theP.08's barrel extension allow the breech block to slide back and forth. On the left side, the sear makes its appearance midway in the slot, and protrudes from the upper left rail into the assembly to engage the catch on the firing pin when the breech block is returning to battery, thus coc*ing the gun. The catch on the firing pin on either original or conversion breech block is located in between the end-to-end parallel rails on the block's left side, which guide the block in the barrel extension. These rails are supposed to straddle the catch on the sear, so the block whiffs past the sear except for when the catch on the firing pin is encountered, in which case it would spring/slip by on the way back, and the two catches would catch on the way forward. Got it? Anyway, the lower rail on the conversion breech block's left side protrudes too far up and the top, inside corner of it takes up a bit of the space needed for the sear's catch to ride by the breech block's rails without touching them.
So, like the old movie title, something's gotta give. Removal of material would be indicated, so I need to decide whether it's coming off the rail on the breech block that bumps into the sear's catch, or from the bottom end of the catch itself, maybe some from each.
My instinct is to work on the accessory rather than the gun, which is a refinished DWM 9mm 1917/1920 military with a force-matched bbl., a shooter. I will try the kit's block in the top ends of my other Lugers to check for fit, but I suspect the kit as the main offender.

Second, the minor annoyance is that the mag is not particularly held in by its catch, seems a bit loose overall. Push the mag in, it sorta clicks into place; turn the gun upright and give it a shake, and bloop--out comes the mag. I thinking a shim applied to the mag in the appropriate spot may do the trick. I've noticed that the dimensional difference between mag well in a 9mm P.08 and the .22 lr round is taken up just about entirely by the thickness of the mag's walls! And that the radius of the mag's rounded side seems less than what would nicely fill the well in this area.

I welcome any comments, questions, or guidance.

David Parker

[John Sabato]

David, while I have a 50+ year familiarity with the P.08 design, I have had limited experience with the .22 conversion kit, and have never owned one myself ( I came close a couple of times, but when I found one at the right price, my wallet's contents were insufficient to complete the purchase).

Your description may suffice IF one can see the parts involved, but I can't picture the issue of interaction between the conversion kit and donor Luger in my head...

I think a good photo essay by you on the parts involved would evoke the necessary solution to your problem from the intelligence collective here on the forum... and at the same time, educate those new enthusiasts who have little or no familiarity with the design and function of the conversion kit...

I highly recommend that you attempt assembly with one or more of your other Lugers and see if the problem exists... if it does, then the kit is a fault... and it is where I would make any modifications... I presume that your focus is functionality and not collectibility... I will watch the new responses to this thread with great personal interest.

[Vlim]

I have experimented a little with the Erma .22 lr conversion kits, both the pre-war and the 1980s SE/08-2 version.

Overall I'm not impressed with the quality of the sets. They are prone to jamming and getting one to work flawlessly is almost impossible. The first set I tried, which consisted of a mismatched barrel / toggle combination worked well until the barrel freed itself from the chamber. It appeared that Erma hard soldered the barrel bit into the chamber part, and this worked loose over time.

The next step was to replace the barrel (after some failed attempts to repair the other one). But this produced an interesting side effect. Although the barrels are both numbered in the 4000-range, they are actually different in a critical area, the position of the chamber is higher on the replacement barrel, causing the .22lr rounds to strike it's edge. 9 out of 10 rounds will stick and have to be refed manually.

The second set, the SE08/2 works slightly better (barrels are not interchangeable between sets), but the toggle refuses to close fully 9 out of 10 times.

Period documentation suggests that the German army and police also had issues with these sets, it was ordered to mate the sets up with one particular pistol and keep the set and pistol together. Which suggests that these sets do require a certain amount of fitting and fiddling around with to get them working with a particular gun.

If you want to shoot .22lr with a luger-like pistol, get a Ruger

[ithacaartist]

John, I just now tried the breech block in my 29/70 Interarms Mauser, and it's smooth sailin' in the top end of this one. The catch of the Mauser's sear is narrower across its catching edge, thus the slot in the breech block is big enough to allow it to pass freely along. Duh, they're the same vintage, as Gerben suggests. That pistol would have been my first choice, anyway. I consider it slightly more expendable than the rest; the reason I didn't try it in there in the first place is that I'd need to make a new spacer to reconcile barrel lengths. So, I will make a new spacer to fit, and see if I can get it to function.
And will post suggested pics soon as I can.
I do intend to try the setup out, and shoot it once in a while.

Gerben, buying a Ruger .22 is on my list, but I'm a glutton for punishment, as you may have been able to tell from my postings about the La .22's. From that experience, so far, I've come to expect things made by Erma to be cranky about fit and function--but not impossible. I find satisfaction in the experimentation and attempts at tuning/adjusting, particularly when they pay off a little. My goal is to fit the kit to a pistol and coax it to work as well as possible. A one-shooter may be the best that can be accomplished, but it will be fun finding that out. (This kit is an 80's Interarmco.)

Predictably, this conversion kit arrived without any related paperwork or instructions. Therefore I am completely in the dark as to how to deal with the ejector while installing or removing the barrel liner. I have a clever approach in mind, but it would involve a toothpick; and I think there is likely a proper procedure. So I'm now asking if anyone has appropriate printed instructions available, or could just show me the ropes as to what to do to get the extractor's business end out of the way while fitting kit parts.

No luck on the rattling mag. Its fit in the Parabellum is still rattly and unstable. I've noticed that the follower button sits lower in its empty position than a P.08 mag. It influences the holdopen about half what it should. so must be careful of this when (if?) I get to the end of a mag. for fear that the little of the holdopen's tip that sticks up may not be strong enough to withstand the forces involved when the returning block encounters it. The mag stays in if I press it to the side of the well that has the catch. A simple shim taped to the opposite side would keep it where it would be held by the catch, but then I'm wondering if throwing it off-center like that, however slight, may cause issues with how the lips line up with the breech block and chamber. I'll keep y'all posted...

[Vlim]

It is very well possible that the postwar Erma SE08/2 was actually designed and tested around the postwar Mauser Parabellum for several obvious reasons:

-They were available.
-Mauser had already played with the idea of doing a .22lr version of the Parabellum.

Mauser actually hoped that Erma would go out of business, so they had access to their equipment, parts and design of the .22lr conversion set. Against expectation, Erma bummed around long enough while avoiding bankruptcy, so Mauser never acquired the Erma tooling.

[TheRomanhistorian]

David,

I've followed your Erma threads with great interest and I'm curious how the conversion kit turns out. Will this be a permanent conversion for this particular pistol then?

Michael

[Vlim]

Ah, about the ejector.

The pre-1945 Erma kit had no separate ejector, the pistols ejector would be removed and placed in a compartiment in the storage box for safe keeping. The magazine had a small extension which worked as an ejector.

The SE08/2 has a separate ejector which loosely fits in the same area as the original ejector, which needs to be removed prior to installing the SE08/2.

It is a bit wobbly and loose during installation, but will remain in place once all is assembled.
Basically, it just drops in.

Ah, note that there are actually 2 versions of the SE08, one with the old style ejector (magazine based), and one with the new style ejector (separate part) and a feed ramp on the barrel insert.

--PDF copy of Interarms SE08 manual attached! (1958 first version).

[ithacaartist]

Not meant as a permanent conversion, but it fits only this version of the pistol, so I'll keep the two together. When shooting 9mm gives me too much of a beating, I can change over when I feel like it. It's no more involved than field-stripping--or I think it will be, as soon as I get the breech block/extractor aspect sorted out.

I've edited the above post, and now this one, because I kept typing extractor when I meant ejector. The ejector lines up with the block on the breech end of the barrel line. The liner will click past It when inserted, but this seems a sketchy move, to me. Removal of the liner is impossible until the ejector is sprung and held completely out of the way--also a sketchy move, I think. A toothpick wedged behind the extractor on the outside of the pistol once the extractor is sprung out, would do it gently; but I'm not trying it until I finish gathering opinions, if then.

[Vlim]

The later SE08/2 manual consists of only 2 pages of info and an exploded parts view. The info is repeated in German, English and French.

Here it goes:

Description of the ERMA Conversion Unit SE 08/2
The conversion unit consists of the following main components:
Breechblock complete, barrel with barrel guide cover, knurled nut and lock nut, magazine, ejector, rear joint bolt (2-part) and assembly bolt.
The conversion unit is inserted into the Parabellum pistol in the following order:

1. Remove magazine and unload pistol completely (see safety instructions).
2. Remove cover plate, dismantle breechblock and ejector.
3. Insert conversoin unit from the rear (extractor slot facing upward) and screw tight with barrel guide cover and knurled nut. Fix with spring washer and lock nut.
4. Insert SE 08 ejector into the fork-shaped receiver.
5. Push SE 08 breechblock complete into the fork-shaped receiver and fix with the rear joint bolt.
It should be observed in doing so that the bushing is inserted on the left side (in shooting direction) and the rear joint bolt pushed in from the right.
6. Insert SE 08 magazine.

The safey of the original pistol remains completely functional.
In cocked condition, the firing pin is visible on the rear joint. It projects at the rear end of the pistol.
Firing is done now with the same motions as with the original weapon:
1. Release safety (safety lever forward).
2. Load magazine and push it into the pistol.
3. Pull breechblock to the rear and let it go forward under its own spring power. In this way, the first cartridge is loaded into the chamber. The weapon is cocked, the pin is visible.
The pistol is now ready to fire.
The toggle joint action remains open after the last shot. To avoid failures, teh conversion unit should be cleaned after shooting and treated with acid-free oil.

[ithacaartist]

My kit looks like the .pdf pics, no feed ramp, no separate ejector.

[Vlim]

In that case, the original ejector must be removed, and the .22lr magazine will function as the ejector.

[regul]

David
I have attached a pdf file of the ERMA Manual.
Thanks
Ed

[regul]

Vlim
After looking at this post again I realized you had already attached the ERMA Manual.
I have two of these sub caliber coversion units I got in the early 90's.
Thanks
Ed

[ithacaartist]

Originally Posted by Vlim

In that case, the original ejector must be removed, and the .22lr magazine will function as the ejector.

Ah, note that there are actually 2 versions of the SE08, one with the old style ejector (magazine based), and one with the new style ejector (separate part) and a feed ramp on the barrel insert.

Gerben,
The kit appears complete. Once I found the Mauser Parabellum to have the receiver that accepts the kit breech block, I took a look at the ejector situation. The kit's block is relieved on its lower right edge and clears the regular ejector fine. In addition, the relief cut's front end emerges in the proper quadrant of the block's milled area for the flange of the .22 round, so it would appear that no replacement or removal of the original ejector is necessary. When I finish up making a new adapter collar for the barrel insert, I'll check everything for clearance, then cheek to see if it will eject an empty casing as desired.

To install the kit's barrel insert, it is necessary to clear a path for the rectangular lump--which is its breech end, in order for it to slide in between the receiver forks all the way forward. Using a plastic probe, I pushed the business end of the regular extractor toward the outside of the fork, then from the outside used a plastic wedge between it and the outside of the fork to hold the extractor so that its tip, inside, was just flush with its slot. This arrangement allowed slick passage for the barrel insert, which slid very nicely into place.

The way this setup went together would lend credence to the idea that this kit was made for this style/mfg. of Luger. My adaptation of it to accommodate my pistol's barrel length, is needed because this kit was made to fit the Mauser 06/70 variation of the P.08, which most often sports a 4" bbl.


Next, the case of the errant mag.

[ithacaartist]

Update on conversion kit...
I'm reaching for the salt and pepper, preparing to eat a few previous words: The original ejector is indeed in the way if left in place. Though the relief slot on the bottom of the breech block rides at a level to clear the extractor, I finally noticed that it is not wide enough to accommodate the ejector without tickling its tip on the way past. The right rear lip of the mag comes up higher than the other side, which puts it right where it needs to be for its forward corner to take the place of the tip of the original extractor, as Gerben said. My installation of the mag confirmed that if the original extractor is left in place, the two interfere.
OK, now with the original extractor out of the way, there was still a drag in the action. Good lighting and magnification revealed that a couple of licks with a file to the top of the mag eliminated this slight contact. Indeed, the mag now clicks nicely into place, as this tiny extra dimension also kept it from doing this.
I'd already reproduced the adapting sleeve in a shorter version, a bit less than an inch in length, so the insert barrel is now adapted to the Mauser 29/70's six inch barrel. The plan is to salt blue the new part I've made, to match the rest.
With all assembled, I tried a few test mags of different stuff. The kit functions now at least as well as my Erma .22 pistols. The 5-shot mag's spring seems extremely wussy, but it worked most reliably on the last 3 rounds of each mag. I'll try a comprehensive ammunition test and see if the system has any preference in this realm. The left front lip on this mag is made of a piece of spring steel fastened to the top of the mag body. This provides a slight friction to the front of the round as it rises while being pushed by the returning breech block. My notion is that this setup provides a mechanicaly "calming" effect on the round during the first part of its travel to chamber, in contrast to the symmetrical steel lips of the plain .22 Erma mags, and the headlong free-flight trip to battery the round makes in the Erma pistols.

[alanint]

Gents,

Bookmark this site for manuals for almost any gun or accessory you ever hope to own..


http://stevespages.com/page7b.htm

[Ron Wood]

I have been following this thread with some interest. I applaud anyone that takes the time to make a Luger .22 conversion a workable and enjoyable endeavor. David, I wish you much success in your "tinkering"...if you get something to work reliably you will have attained wizard status.

I have some "project" pieces that I have accumulated for much the same effort that you have undertaken. I acquired an American Eagle barrel/receiver that someone with a bit of skill modified. The original caliber was 7.65mm, but the converter bored it out to 9mm to accept a 9mm/.22 caliber barrel insert that was permanently installed. I then happened upon a relatively scarce .22 conversion toggle assembly with an adjustable rear sight. You can see from the photos that the sight is adjustable both in elevation and windage. The blade of the sight is a rough replacement, but I will eventually replace that with one a little more refined.

I have also acquired a couple of magazines to play with. The 10-shot is an early post-war piece that is pretty nice. The 5-shot example is from a military practice conversion unit, stamped Eagle/132 on the spine that someone "thoughtfully" engine turned the body. In defense of their efforts, I suspect it was to improve a rusted or deteriorated exterior. It looks kind of neat so I won't mess with it.

Someday when I get a few more of my projects out of the way, I hope to put these pieces together on one of my guns and burn up some ammo!

Keep up the good work David. I hope you find the right combination.
Ron

[ithacaartist]

I consider the time I spend "tinkering" to be just about the most satisfying time of my day. I'm looking into the possibility of working for GunBlack in Interlaken, NY. I called for a quote for bluing my barrel insert adapter sleeve, and he said, laughing, "A 12 pack of beer!" They finish thousands of parts in some orders, so I guess that custom work is the exception rather than the rule. They offer Parkerizing, bluing, and some other surface treatments and coatings, I see by their website. Anyway, it looks like it will be easy to have my sleeve match the rest of the kit. I'll ask about salt bluing when I go up there.

Ron, If I'd encountered a rig like that one, you bet I'd have tried to get it! A novel approach, to adapt the barrel to the kit, instead of the other way around! What's the condition of the Luger--did someone to this to an all matching? I presume the original top end is gone... And I think that adjustable rear sight is just the cutest thing.
The mag with mine is a 5-shot. You can put eight into it; there's room. But the way the follower is shaped presents the 1st of six or more rounds at an angle that dooms proper chambering before it starts. I've noticed that the Erma pistol style of 22 mag has a follower that seems to pivot according to how many rounds are in the mag, maintaining a reasonable angle of pre-launch, let's say, for each round that sit at the top of the mag. Uh-oh, now I'm thinking 10 shot for a conversion mag by using some guts from one of the 10-shots.

I would be interested in a spare conversion kit mag, to compare the performance of another individual. And an extra is also good to have.

[Ron Wood]

David,
I purchased the barrel/receiver already altered as you see it. I have no idea where the rest of the gun is.

[ithacaartist]

I went through a few mags yesterday afternoon in an attempt to discover if the conversion kit was as sensitive to the type of .22 round as the Erma pistols have proven to be.

CCI MiniMags, solid round and HP, both Cu plated
Eley Sport, 40 gr. LRN
Winchester 36 gr. Cu plated HP
1 round CCI Stinger

The results were not particularly informative, as all performed about the same. MiniMags proved the best so far, by a slight margin. The big exception was the Stinger round. These babies are rated at over 1600 fps, their casing is silver colored and noticeably longer than other choices, and the sound of the report, simply put, was a bit frightening. I took out the mag after that first shot and returned the remaining 4 rounds to their box, to be saved for use with my Ithaca/Erma action lever action saddle gun.

Gripping the Luger for each shot--initially using my left hand to cup the bottom of the pistol and right hand--gave pause for thought. I noticed that this positioning of the cupping hand, which I've used for firing full-caliber shooting, pushed up on the mag, which has just a touch of vertical play. The hand position definitely holds the bottom of the mag firm, but then I saw that the top of the mag seemed to move a bit laterally from its position at the top compared to not snugging it from below. The potential for two situations, when cupped, occurred to me. First, the lateral displacement could shift the center line of travel of the round between the mag top and chamber; and perhaps influence the mag lips to contact the part of the breech block's bottom which they straddle. The area in question on the block is what pushes the top round from the mag top, or encounters the holdopen lug onthe back end the mag's follower Second, the slight vertical change in position of the mag seemed to reinstate the drag/contact between the top of the mag lips and the bottom of the breech block. Overall, the conversion kit has chambered rounds more effectively than the Erma pistols, so I'm thinking that the drag on the action was the more potent aspect in causing failures. It all works a little better if my hand is not holding up the bottom of the mag while shooting.

The issues that remain are centered on failure to eject properly, simple misfire, and failure to co*k reliably. I've cleaned and lubed the system thoroughly again,, checked the condition and alignment of the catches on sear and f.p., and the cocking went a bit better, though I'm still getting practice in clearing the action out/re-cocking.

To date, my "tinkering" has improved the reliability overall maybe another 33%, up to ,say, 80+% from around 60%. I'm not able to blaze away flawlessly, to be sure, but I've nudged the experience from frustrating to a bit of fun, so I'm satisfied for the time being.

My final observation of this conversion kit installation is that there is a very small bit of extra dimension in the top end internals--the rectangular lump on the breech end of the insert barrel + the toggle train from face of breech block to center or rear toggle pin. With the rear pin removed, and the action pressed fully into battery so as to eliminate the space established by the tension of the extractor in its notch over the chamber, I could see the misalignment of the two sets of holes the pin slides thru. It is enough thousandths of an inch to make the toggle assemble seem too long for its position in battery. I checked this because I noticed that the toggle train does not lie quite flat/parallel to the rails of the barrel extension, viewed from the side, daylight is visible under the links, above the side rails. I do not deem this an unsafe situation, as the "knee" joint in these toggles doesn't actually lock like those in original Lugers. It just looks a little funky. The remedy I'd propose is to chuck the insert barrel up in the lathe and remove a whisker from the front face of its rectangular block, where it meets the original breech of the pistol. So, now I'm asking for observations/comments about this approach to this mostly aesthetic issue.