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.