How to fix a bent barrel extension?

[Olle]

Does anybody here know how to fix a barrel extension with a bent rail? It's about 1/8" off at the very end, and it seems to be bent right behind the chamber. I'm afraid to just try and bend it back, would rather leave it to somebody who knows what he's doing.

[G.T.]

Hi Olle, It can be done, but you have to be carful?? Also, you have to get it right pretty quick, as the are probably not dead soft and maybe will crack due to work hardening or temper... But, you'll get a couple of shots at it... you need, a good vice, some brass, steel, and probably some aluminum plates and pieces... First things first, using a digital caliper, measure across the width at the chamber, this is your base measurement... next using a machinists straight edge, or square.. check along the sides using the chamber area as your guide, and see which rail is bent, either in or out, or perhaps even twisted some... Then it's just a matter of, blocking, spacing, clamping, SQUARELY, the receiver in a vice with protective blocks, and springing the rail slightly past the yield point and check for straight... over and over... also, holding or clamping a long vertical straight edge on the receiver sides at the main pin area, will show if you have twist... again, clamp some blocks on it and twist it back, with a little bit allowed for spring back as before... It should display some memory, and you will be surprised how close you can get it...Just make sure of where you want it to yield.. as you don't want wowies... ... When the back is square and straight, it sould measure within .002" or "003". probably +.000" /- .003", You'll know a hell of a lot more when your done! .... best to you, til...lat'r....GT...

[DavidJayUden]

I had an old Artillery shooter break right there...
dju

[sheepherder]

Originally Posted by Olle

It's about 1/8" off at the very end, and it seems to be bent right behind the chamber.

Do you mean the 'fork' is bent-in one hundred and twenty-five thousandths??? That should show up on a picture pretty good, but I don't see it...

I've had a twisted and Z'd Luger extension back in the 80's...Took a long time to get it straight...Months, maybe even a year...Nudging it a bit more every couple days...When I was done, It was straight again, and I looked at it and proudly said...

















NEVER AGAIN!!!

Box yours up and ship it off to Gerry Tomek.

[Olle]

Originally Posted by postino

Do you mean the 'fork' is bent-in one hundred and twenty-five thousandths??? That should show up on a picture pretty good, but I don't see it...

I've had a twisted and Z'd Luger extension back in the 80's...Took a long time to get it straight...Months, maybe even a year...Nudging it a bit more every couple days...When I was done, It was straight again, and I looked at it and proudly said...

















NEVER AGAIN!!!

Box yours up and ship it off to Gerry Tomek.

I measured with calipers and it's more like 3/32", 0.095" to be exact. You can't really see it in the picture, but the right rail is bent pretty bad.

The left rail appears to be straight, so I was thinking along the same lines as GT: Clamp it in some kind of fixture, then bend it a tad over to allow for springback. What I had in mind was to clamp the left rail to a straight surface, and also clamp the chamber really tight to make sure that the left rail won't bend. The next step would be to fabricate a small machinist's jack, set up a dial indicator and start spreading it about 1" or so behind the chamber. Spread it a bit, take a reading, check the result, spread a bit more, take a reading, rinse and repeat until it's straight. A slight "Z" won't bother me all that much, this will be refinished anyway so I'd rather file/polish the last few 1/1000 than working it until it cracks.

Then again: I might chicken out and I need for someone to remove the barrel as well, so are you up to the challenge, GT?

[G.T.]

Sure thing! I'll certainly give it a go.... But, send the toggle train with! Best to you guys, til...lat'r....GT

[sheepherder]

Originally Posted by Olle

A slight "Z" won't bother me all that much...

...Until you try to put the toggle axle pin in...It's pretty much a precise fit...

Part of the problem with 'spreading' the sides is that both sides want to spread at the same time whether you support them or not...I toyed with the idea of making a special mandrel to insert into the receiver, with a drilled & aligned hole for a 8.82mm rod that would enter the barrel...Then you could work on 'spreading' the sides one at a time...

I do have a brass receiver insert for my barrel swaps; in an emergency (which is doubtful in my future) I could drill it and insert a squib rod to make a shade-tree fixture...But that axle pin is the most oddball size ever designed; not Metric and not Yankee...Not Inch, not Letter size, not Number size...You'd have to make up a special pin (or use a spare axle pin) to test your alignment after every tweak...

...Or just box it up and send it to Gerry!!!

[Olle]

Originally Posted by postino

...Until you try to put the toggle axle pin in...It's pretty much a precise fit...

Part of the problem with 'spreading' the sides is that both sides want to spread at the same time whether you support them or not...I toyed with the idea of making a special mandrel to insert into the receiver, with a drilled & aligned hole for a 8.82mm rod that would enter the barrel...Then you could work on 'spreading' the sides one at a time...

I do have a brass receiver insert for my barrel swaps; in an emergency (which is doubtful in my future) I could drill it and insert a squib rod to make a shade-tree fixture...But that axle pin is the most oddball size ever designed; not Metric and not Yankee...Not Inch, not Letter size, not Number size...You'd have to make up a special pin (or use a spare axle pin) to test your alignment after every tweak...

...Or just box it up and send it to Gerry!!!

I was thinking about supporting and clamping the barrel, instead of using a rod in the bore. If you lay it flat on its side and clamp it both at the muzzle end and right at the chamber, you would only be bending one rail... or?

But yeah, boxing it up and sending it to Gerry sounds like a safer alternative.

[Olle]

Originally Posted by G.T.

Sure thing! I'll certainly give it a go.... But, send the toggle train with! Best to you guys, til...lat'r....GT

GT,

You have a PM...

[sheepherder]

Originally Posted by Olle

I was thinking about supporting and clamping the barrel, instead of using a rod in the bore. If you lay it flat on its side and clamp it both at the muzzle end and right at the chamber, you would only be bending one rail...

Just out of curiosity, where do you intend to apply pressure on the rail to bend it???

BTW, is there an amusing story behind how this rail got bent???

(Mine got bent when I removed the barrel without proper tools)...

[Olle]

Originally Posted by postino

Just out of curiosity, where do you intend to apply pressure on the rail to bend it???

BTW, is there an amusing story behind how this rail got bent???

(Mine got bent when I removed the barrel without proper tools)...

My approach would be to lay it with the left side down on a fixture (for example, a heavy aluminum block) and clamp the barrel, the chamber and the left rail securely. This would leave the right rail unsupported. Then I would insert a machinist's jack between the rails and push, while reading with a dial indicator at the end of the rail. I can make a spacer block (using another Luger to get the correct dimension) to get a fairly accurate base reading for the indicator, then I'd push beyond that a bit.

After doing this in increments a few times, I should get a pretty good idea of the springback. After the final push, it should spring back to the base reading. I'm sure there will be some fine tuning after that, but this should get it back within reasonable tolerances. Well, that's what I had envisioned anyway.

It was bent when I got it so I really don't know what happened to it, but it takes a lot of force to get a breech block in between the rails so somebody must have squeezed it pretty darn good. There are some bad diagonal gouges on the rails, almost like the extension has "derailed" at some point, and I'm sure that this has something to do with it. I might even take it to a machine shop to have it crack tested before I go any further, I definitely don't want it to break.

[lugerholsterrepair]

DANGER! Will Robinson! DANGER!

[ithacaartist]

Here's another caution to consider: When bending a steel structure to and fro, forces act upon the weakest area along the length of the piece. In the case of the Luger barrel extension, this would be the square, inside corners, where each rail of the extension joins the main meat of the chamber/receiver. When flexed, and particularly if the steel is tempered a bit, this sharp corner will be the first place to show it when the steel begins to tear.

My advice is to stabilize this area with a clamp so that the area in question is not subjected to these forces. Clamping/fixing the part in place is paramount; and all deflective forces intended to realign, are best applied with a clamp, as well, for optimal control, to gently squeeeeeeze. Avoid sharp blows to the setup at all cost, even with soft or padded whackers.

Of course, the safest way is to forge/heat bend the offending arrangement back into submission. However, this would likely mean the part would need to be heat treated all over again. Metallurgically, this would be no big deal, but you'd kiss your finish goodbye, that's for sure.

I had occasion to perpetrate such a disaster upon myself a couple of weeks ago. I'd acquired a stripped frame for an Erma Ep.22 -- their second crankiest gun -- and when the upper arrived from another source, it was bent; BOTH ways. I succeeded in straightening it the hard way first, removing the dip in both rails from front to back using the clamping method to displace it just enough to overcome springback, plus a tad. Now the extension would actually slide into the frame!

My setup for straightening the length of one side, flat-ways -- theoretically the easier of the two ways it needed to move -- was deficient in stability and approach! I'd previously brought a couple of sear housings for these pistols back into true by laying them flat on a non-marring surface and tapping down the high areas with a padded instrument. However, the vibration involved in doing this with a Zamak upper was sufficient to snap off the entire extension and barrel from the side I was working on. Ouch! a $100 mistake, as it turned out... I'd attempt it again, but would use a better setup that would use a clamp instead of a dead blow hammer!

[Olle]

Originally Posted by ithacaartist

Here's another caution to consider: When bending a steel structure to and fro, forces act upon the weakest area along the length of the piece. In the case of the Luger barrel extension, this would be the square, inside corners, where each rail of the extension joins the main meat of the chamber/receiver. When flexed, and particularly if the steel is tempered a bit, this sharp corner will be the first place to show it when the steel begins to tear.

My advice is to stabilize this area with a clamp so that the area in question is not subjected to these forces. Clamping/fixing the part in place is paramount; and all deflective forces intended to realign, are best applied with a clamp, as well, for optimal control, to gently squeeeeeeze. Avoid sharp blows to the setup at all cost, even with soft or padded whackers.

Of course, the safest way is to forge/heat bend the offending arrangement back into submission. However, this would likely mean the part would need to be heat treated all over again. Metallurgically, this would be no big deal, but you'd kiss your finish goodbye, that's for sure.

I had occasion to perpetrate such a disaster upon myself a couple of weeks ago. I'd acquired a stripped frame for an Erma Ep.22 -- their second crankiest gun -- and when the upper arrived from another source, it was bent; BOTH ways. I succeeded in straightening it the hard way first, removing the dip in both rails from front to back using the clamping method to displace it just enough to overcome springback, plus a tad. Now the extension would actually slide into the frame!

My setup for straightening the length of one side, flat-ways -- theoretically the easier of the two ways it needed to move -- was deficient in stability and approach! I'd previously brought a couple of sear housings for these pistols back into true by laying them flat on a non-marring surface and tapping down the high areas with a padded instrument. However, the vibration involved in doing this with a Zamak upper was sufficient to snap off the entire extension and barrel from the side I was working on. Ouch! a $100 mistake, as it turned out... I'd attempt it again, but would use a better setup that would use a clamp instead of a dead blow hammer!

I know what you’re saying, and work hardening is another problem. This is just a slight bend so it’s hopefully not enough to work harden the steel, but I’m sure you know that when you try and bend something back, it won’t necessarily bend in the same place. Many times, you’ll end up bending it right next to the first bend, so some heat may be necessary to prevent this.

I’m not worried about the finish though, it's going to be rebarreled and refinished anyway. By the way, the barrel has a big dent at the muzzle end, and I wouldn’t be surprised if this has something to do with the bent rail. Some people just love to use the BFH for disassembly.

BTW: I don’t agree with your statement about the Erma “Luger” being the second crankiest gun. It is the crankiest gun ever. If it’s of any consolation, I have broken some of those Zamak parts too, so my way of straightening Erma parts nowadays is to throw them away and buy new parts.

[sheepherder]

Originally Posted by Olle

...so my way of straightening Erma parts nowadays is to throw them away and buy new parts.

...Or box them up and send them to Gerry!

[Olle]

Originally Posted by postino

...Or box them up and send them to Gerry!

Ah... Good thing you mentioned it, I'll keep that in mind!

[ithacaartist]

Originally Posted by Olle

...BTW: I don’t agree with your statement about the Erma “Luger” being the second crankiest gun. It is the crankiest gun ever. If it’s of any consolation, I have broken some of those Zamak parts too, so my way of straightening Erma parts nowadays is to throw them away and buy new parts.

Olle, I was referring to the Ep.22 as Erma's second crankiest gun. The all-time "winner" for being a little bi*ch is their La.22. I think the improvements in the Ep.22 trigger system and extra weight of its firing pin result in fewer FTF than the La model. All the models from the 60s are good for practice in clearing jams, adjusting mag lips, and dialing in ammunition according to the relationship the round's power has in affecting the action as it functions! Failure to feed, failure to fire, stovepipes--empty and unfired, failure to eject, are all part of the "fun" of these early guns. I've had slam-fire, ignition of multiple rounds in full-auto fashion, and I've even experienced the entire bottom blowing off the .22 rimfire round, creating a tube open on both ends! One may well wonder how these things could have ever worked!

My faves are the downsized KGP series. These are all steel, save the grip frame, itself. There is no motion, and no particular stress during functioning between the Zamak frame and the steel upper, except for takedown and re-assembly. The only reasonable worry in this case would be dropping the gun, in that the frame will break more easily than one of steel. These guns, .22 cal for the KGP69s, .32 and .380 for the KGP68(a)s, are much better built and finished than their predecessors, La, Ep, and Et.22s, which are predominantly die-cast construction; and they work better, too.

[Olle]

Originally Posted by ithacaartist

Olle, I was referring to the Ep.22 as Erma's second crankiest gun. The all-time "winner" for being a little bi*ch is their La.22. I think the improvements in the Ep.22 trigger system and extra weight of its firing pin result in fewer FTF than the La model. All the models from the 60s are good for practice in clearing jams, adjusting mag lips, and dialing in ammunition according to the relationship the round's power has in affecting the action as it functions! Failure to feed, failure to fire, stovepipes--empty and unfired, failure to eject, are all part of the "fun" of these early guns. I've had slam-fire, ignition of multiple rounds in full-auto fashion, and I've even experienced the entire bottom blowing off the .22 rimfire round, creating a tube open on both ends! One may well wonder how these things could have ever worked!

My faves are the downsized KGP series. These are all steel, save the grip frame, itself. There is no motion, and no particular stress during functioning between the Zamak frame and the steel upper, except for takedown and re-assembly. The only reasonable worry in this case would be dropping the gun, in that the frame will break more easily than one of steel. These guns, .22 cal for the KGP69s, .32 and .380 for the KGP68(a)s, are much better built and finished than their predecessors, La, Ep, and Et.22s, which are predominantly die-cast construction; and they work better, too.

Then we are in perfect agreement! Like they say in Sweden: "There's degrees even in hell", and there is a difference between the Erma guns for sure. Mine happens to be the LA-22 (i.e. the black sheep of the family), and after hours (days, actually) of tweaking I have admitted defeat. I might pick it up and try again, but I'll probably have to get me some Xanax first. Sometimes I believe that the LA-22 is Hitler's last vengeance weapon, and intended to be the ultimate revenge on the American people.

Now, as you're knowledgeable on Erma's products: How about the RX22 PPK clone? I happened to find one in mint condition and I have been debating whether I should shoot it or not. It's a very simple and hopefully fool proof design, but do they really work? Or should I leave it in the box and hope that it will be a collectible one day?

Way off topic, but anyway...

[ithacaartist]

Way off topic...in for a penny, in for a pound. Yes, the La.22 has a special place in hell, close to the hub; the KGPs are in a slightly cooler corner!

Olle, other than the faux Lugers, the only other Erma I have experience with is the model '72 saddle gun, .22 lr lever action. It was purchased from Ithaca Gun's company store as a blemished example (The tapping in the tang for the butt-stock is hanging by only a few threads.).

But by process of extrapolation, as with the 1911 non-Colt knockoffs, I'd think that the basic, sound designs "borrowed" from other successful pistols, if faithfully executed, would work as well built by Erma as any other manufacturer--just as my High-Standard GI 1911, CNC machined in the Philippines, is dependable and safe as any knockoff in its price range. It is even pretty accurate.

I've considered expanding my Erma experience to other models, like an M1 to match my real M1, or a P-22, or one of the small, Colt style autos. I collected the Luger-esque ones because they cost less than original Parabellum pistols, so at this point the immediate future looks sparse for my collecting activities! If I find a nice "collectible" shooter from WWII era, I'll need to tap my retirement account...

David

[Olle]

David,

I believe a large part of Erma's bad reputation is due to the ill-conceived Luger clones, incorporating a toggle in a straight blowback is simply not a good idea (even though I have to admit that the concept is cool).

From my (intentionally) limited exposure to Erma's product, I gather that the rest of them are, just like you suggested, plain ol' knock-offs of proven designs. I don't know if even Erma was able to screw up a .22 blowback, so I assume that the PPK will work just as well as other cheap, zink frame .22s on the market. It actually looks well made, nice fit, finish and so on, the only possible problem would be the quality of the metal. Zink it's just not a good material for guns, especially if you consider the amounts of ammo you usually run through them.