Swiss 22lr conversion

Rick W. · 02-14-2012, 11:44 AM

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ithacaartist · 02-14-2012, 04:31 PM

Rick,
As you may have noticed, I've been dabbling around with a conversion kit. And during this time, I'm also reading Fred Datig's amazing book, in which the single shot conversions are covered somewhat. It would seem that a ramrod was part of those kits, with which the expended round is pushed from the barrel. I think whether the offset is up or down might not make a difference in having the original firing pin strike the rim. Without a different breech block and spring arrangement, the Luger simply will not cycle from the recoil of a .22lr. For the .22 rim to be chambered in front of an original breech block,it would seem to me that a concentrically cut relief step would be necessary at the rear of the chamber of the barrel insert, to accommodate the rim of the .22 round. I'd also think that the offset would also be limited by the fact that the diameter of the base of the .22 round would need to fall within the relief on the face of the original breech block, let in for the heels of the 9 mm or 7.65 mm Luger rounds. Somehow, proper headspace must also be maintained, as you mentioned, and there is definitely a rectangular chunk on the breech ends of the Erma kits, because they have different breech blocks. The other kits apparently also have an extra bit of dimension in that area, if only to keep the barrel in when the nut on the muzzle end is tightened; but I think this structure would also accommodate what's needed to fully support the round, as you said, and allow for placing everything in battery with proper headspace.
Erma was the only source of repeating .22 conversion kits.
For a single shot setup. one would engage the holdopen by inserting an empty mag after the shot is fired. The action is opened by hand, and the mag is then removed after the holdopen has been engaged. Next, use ramrod to push out shell casing, then insert new round and cycle the action, and you're good to go for one more shot. Too bad the extractor or ejector won't work, but such are the limitations unless you go to a different, blowback top end like the Ermas, whether pistol or Luger conversion kit. The original parts can't be influenced enough to fully cycle--eject, co*c, feed--even if the offset system allowed any of the related parts anywhere near the areas of .22 rim they need to show up near, to do what they need to do.

ithacaartist · 02-15-2012, 06:18 PM

Rick,
From the Datig book, and also Gerben's info posted on my other thread, I understand that ejection was handled two ways in the repeaters. One early Erma kit included an extractor which was intended to be swapped out with the original. From the pics Gerben included, one can see a completely different shape of the one for the kit, with an offset, and probably an extended length to put its business end up farther front where it needs to be to encouter a .22 round. My post war kit uses the forward corner of the right rear mag lip to flick the shell out, and the original extractor is either removed and setaside in a safe place, or--as the tinkerer in me decided--its tip pushed out from the inner slide rail and held out of the way by a small temporary plastic wedge between the outside of the rail and the backside of the extractor shaft.
I noticed on mine that the smaller follower button on the mag does tickle the holdopen and raise it slightly when the mag is empty. But the cycling in general does not move the breech block back very far; therefore I am of the opinion that it just can't work with the kit's toggle train, even if a bigger button were substituted.
The kit's holdopen feature depends on the little blip, against which the heel of the .22 round that sits atop the follower rests. When empty, this little hoink sticks up into the path of the breech block. Instead of stripping off a round, the block encounters the little lug and stops, leaving the breech open. Since this is part of the mag, the action will again snap shut the moment the mag is removed.
My concern is the different energies between a .22 lr and the full sized Luger ammo. I'm thinking that since the .22 would be unable to overcome the main recoil spring and firing pin spring in combination, as does a full powered round, one might change out the mainspring if one could be found to accept and release the proper energies, if the mass of the original toggle train can also be influenced adequately by the .22's explosive force. Sufficient oomph to move the action fully back would also allow the original holdopen to come into play, in conjunction with your larger follower button. Compromise may be impossible if the force of the spring which is strong enough to raise the holdopen into position is great enough to start causing feed issues.
I'm starting to confuse myself now, so will stop. Whew!

02-14-2012, 11:44 AM	#1
Rick W. User Join Date: Jun 2002 Posts: 339 Thanks: 81 Thanked 359 Times in 198 Posts	Swiss 22lr conversion aaa Last edited by Rick W.; 08-30-2015 at 07:41 PM.

02-14-2012, 04:31 PM	#2
ithacaartist Twice a Lifer Lifetime Forum Patron Join Date: Mar 2011 Location: Atop the highest hill in Schuyler County NY Posts: 3,282 Thanks: 7,007 Thanked 2,476 Times in 1,319 Posts	Rick, As you may have noticed, I've been dabbling around with a conversion kit. And during this time, I'm also reading Fred Datig's amazing book, in which the single shot conversions are covered somewhat. It would seem that a ramrod was part of those kits, with which the expended round is pushed from the barrel. I think whether the offset is up or down might not make a difference in having the original firing pin strike the rim. Without a different breech block and spring arrangement, the Luger simply will not cycle from the recoil of a .22lr. For the .22 rim to be chambered in front of an original breech block,it would seem to me that a concentrically cut relief step would be necessary at the rear of the chamber of the barrel insert, to accommodate the rim of the .22 round. I'd also think that the offset would also be limited by the fact that the diameter of the base of the .22 round would need to fall within the relief on the face of the original breech block, let in for the heels of the 9 mm or 7.65 mm Luger rounds. Somehow, proper headspace must also be maintained, as you mentioned, and there is definitely a rectangular chunk on the breech ends of the Erma kits, because they have different breech blocks. The other kits apparently also have an extra bit of dimension in that area, if only to keep the barrel in when the nut on the muzzle end is tightened; but I think this structure would also accommodate what's needed to fully support the round, as you said, and allow for placing everything in battery with proper headspace. Erma was the only source of repeating .22 conversion kits. For a single shot setup. one would engage the holdopen by inserting an empty mag after the shot is fired. The action is opened by hand, and the mag is then removed after the holdopen has been engaged. Next, use ramrod to push out shell casing, then insert new round and cycle the action, and you're good to go for one more shot. Too bad the extractor or ejector won't work, but such are the limitations unless you go to a different, blowback top end like the Ermas, whether pistol or Luger conversion kit. The original parts can't be influenced enough to fully cycle--eject, co*c, feed--even if the offset system allowed any of the related parts anywhere near the areas of .22 rim they need to show up near, to do what they need to do.

02-15-2012, 06:18 PM	#3
ithacaartist Twice a Lifer Lifetime Forum Patron Join Date: Mar 2011 Location: Atop the highest hill in Schuyler County NY Posts: 3,282 Thanks: 7,007 Thanked 2,476 Times in 1,319 Posts	Rick, From the Datig book, and also Gerben's info posted on my other thread, I understand that ejection was handled two ways in the repeaters. One early Erma kit included an extractor which was intended to be swapped out with the original. From the pics Gerben included, one can see a completely different shape of the one for the kit, with an offset, and probably an extended length to put its business end up farther front where it needs to be to encouter a .22 round. My post war kit uses the forward corner of the right rear mag lip to flick the shell out, and the original extractor is either removed and setaside in a safe place, or--as the tinkerer in me decided--its tip pushed out from the inner slide rail and held out of the way by a small temporary plastic wedge between the outside of the rail and the backside of the extractor shaft. I noticed on mine that the smaller follower button on the mag does tickle the holdopen and raise it slightly when the mag is empty. But the cycling in general does not move the breech block back very far; therefore I am of the opinion that it just can't work with the kit's toggle train, even if a bigger button were substituted. The kit's holdopen feature depends on the little blip, against which the heel of the .22 round that sits atop the follower rests. When empty, this little hoink sticks up into the path of the breech block. Instead of stripping off a round, the block encounters the little lug and stops, leaving the breech open. Since this is part of the mag, the action will again snap shut the moment the mag is removed. My concern is the different energies between a .22 lr and the full sized Luger ammo. I'm thinking that since the .22 would be unable to overcome the main recoil spring and firing pin spring in combination, as does a full powered round, one might change out the mainspring if one could be found to accept and release the proper energies, if the mass of the original toggle train can also be influenced adequately by the .22's explosive force. Sufficient oomph to move the action fully back would also allow the original holdopen to come into play, in conjunction with your larger follower button. Compromise may be impossible if the force of the spring which is strong enough to raise the holdopen into position is great enough to start causing feed issues. I'm starting to confuse myself now, so will stop. Whew!