Dave, I have CAW Borchardt C93 and two MGC MP40's (from the sixties), but not the Luger.
I am somewhat surprised that this modelgun is so radically different in function from a 'real' Luger. The CAW C93 is a direct 1-to-1 copy (Japanese site shows interchangeability of CAW and Borchardt parts). The MGC MP40's are also mechanically identical, and share some parts interchangeability with 'real' MP40, but gauge of steel is thinner.
Smootik on MP40modelguns.com is like the Master Collector of modelguns, and Cerwyn [site owner] is not far behind. They have both commented on my C93 review and MP40 postings there. Nice guys, very friendly and helpful. Cerwyn is in UK and has a large collection, as does as Smootik.
What is so fascinating about the Japanese modelguns is the 'cartridge'. In these modelguns the firing pin is fixed in the barrel/chamber, and it intrudes into the screw-apart cartridge to fire the cap (cap is almost like a primer). The cap produces enough noise, sparks, and recoil to look realistic. (The barrel is not solid but has channels so sparks/smoke come out muzzle).
And they are expensive.
