1936 S/42. I've fired this Luger before with milsurp Finn machinegun ammo and my own handloads using 124 gr RN FMJ with nary a hitch. Load on both these was 4.7 grs Unique with NOE 134 gr boolit diameter .358". Magazines are Triple K and Meggar and both have worked flawless prior.
About half the time the bolt was failing to strip the top round off. But there were strings of 3, 4 and 5 rds rapid fire that ran like a champion race horse.
I have some ammo from yesterday unfired. First thought is to seat the bullets .005 to .008" deeper and re-run the taper crimp. I used the OAL from Lyman and it wasn't the exact same cast bullet. I will also take some of my older FMJ and run a couple magazines through just to eliminate some unknown possibility. I've shot about 300 rds through this pistol since first acquired in 1998. (Southern Ohio Gun Dist.). It was missing the magazine and had East German police grip panels. Only a couple mis-match numbers. Its a fun shooter.
The S&W MP 4th change: mfg about 1923 and has J.P.D. 33 on the grip. Almost no blue remains. At least 2 factory star stamps indicating factory re-blue. And there are dates stamped into the grip frame from 1933 up to 1971. Despite its hard ~holster~ life the bore is excellent and the double-action is smooth and perfect timing. I shot it rapid fire and it never skipped a beat.
Books:
Fast & Fancy Shooting by Ed McGivern.
Luger Pistols by Fred Datig, revised edition (very outdated)
yes I know... too much LLA