Modification of a Standard Upper to .22

[sheepherder]

Originally Posted by ithacaartist

I have lots of all these springs, in case you need some.

Dave, I don't need any at this time; I'm just trying to figure out what Patrick Villiers meant about replacing the Erma SE 08/2 kit springs with a 'P38 mainspring'. I don't see how that would work. A chopped-down P-38 recoil spring looks more likely. My experience (in '.22 Long barrel' thread further down in the forum) was that the springs were too strong. Both the Erma firing pin spring and the recoil spring absorb .22 recoil until the firing pin cocks, then it's just the recoil spring. It wasn't recoiling far enough to eject or chamber a round.

The entire cannon assembly has to recoil the ~1/4" in order to line up the magazine with the barrel/chamber. Otherwise the cartridge won't be picked up by the breechblock. The breechblock has to recoil all the way or the spent case won't hit the Erma ejector.

The Erma toggle assembly I tested wasn't going back any further than ~3/4" and with one frame it was binding.

I couldn't do any physical changes because it wasn't my Erma kit and I wasn't about to machine my Luger.

Weaker springs sound like the next step in getting that particular kit to work, but Patrick's comments are pretty discouraging vis-a-vis Erma .22 kits collectively.