When NUMRICH received the drums, the magazine catch notch was located approx. .080" too high, which in turn, means the drum sets too low in the Luger to effect proper ejection! (I know, me too, it took me 6 months and two cases of ammo to figure that one out!!!!)

... Anyway, one of the major operations in the revision is to weld up the mag. catch notch on the drum, (no small feat in it's self!) re-radius the front spine inside and out, and re-mill the notch in the proper location, same as an original...
Having done that, the loader has to have the stop ears at the top, formed upwards, so the magazine will index correctly, and snap into the loading tool! Soooo, it means, the loader will work on all NUMRICH drum that have been revised, and most all original drums, especially BING manufacture... I sometime also relieve the mag catch cross pin so it engages deeper and as a result, hold it more positively.. Bill has it pretty much nailed, I try to make them as close to original as possible.. Not perfect! But, I'd say it's an easy 95% of what an original is?... Just my opinion, mostly doing them so forum members have a little "Luger spice" in their shooting range bag!

... best to all, til….lat'r….GT.....