a fellow rimfire afficianado on assaultweb.net sent me one of his spare 20-round mpi69 .22 rimfire trainer rifle magazines.
it arrived this morning and i though i would take time out to describe what a team of ddr/east german engineers (that should have been off designing porsches for the west!) would go thru to make a simple .22 training magazine.
first, start with a blued steel ak47/akm magazine body. the finish on this example is about 80% with pleanty of wear showing in the expected areas that come in contact with the rifle. the workmanship is typical of the east german military gear from the '70's...very good. this mag was obviously used and used a lot. i rate the overall condition as 'good to very good', all things considered.
this one is serialized with the number 034.
grind the flanges off the bottom...the ones that hold on the floor plate. grind off the feed lips, too, while you are at it.
edit...after a trial loading, it appears to be only a 20-round capacity AND the lower assembly must be dropped in order to get the last 10 rounds inside.
punch not one, but two push-button detent holes (one has an impressed area that allows the bottom portion of the inner .22 mag to drop about about one inch. why? who the frick knows what those damn germans were thinking? store the mag loaded? increase capacity???) in the right side.
punch two roll pin holes and two rivet holes thru both sides of the top of the mag outer body. these retain the steel inner .22 mag body AND the two-piece adapter body that locates the small mag inside the big one. the adapter is made of some sort of pea-green plastic.
are you still with me? good!
the .22 mag body uses a conventional looking follower that is made of steel and a long, fragile looking spring to drive it that is wound from some very thin wire.
perhaps the lower drops in order to keep tesion off of this delicate spring?
now...bacl to that movable lower...
the lower is made of two pieces of that pea-green plastic that have been glued and riveted together. this assembly contains the bottom of the sprig and a really funky spring guide! the spring guide doubles as the mags 'inner' floor plate (in a sense) and is retained in the plastic bu a spring-loaded pushbutton. that is the push-button mentioned above and it retains the entire lower assembly inside the outer mag body...in those two positions i mentioned earlier.
if you are STILL with me, you are entiitled to a docorate in mechanical engineering!
no less than 21 pieces are required to manufacture this magizine! the rear rib contains SEVENTEEN spot welds! the front lap seam has at least eleven spot welds.
to say it is complex is akin to stating that a ferrari boxer berlinetta is a good commuter car.
you can find a rifle and mag conversion thread goping on here: p077.ezboard.com/fparallaxscurioandrelicfirearmsforumsfrm23.showMessage?topicID=1186.topic
this has a couple of nice pics of the rifle and some test targets.