Quote:
Originally Posted by sheepherder
John -
I am looking at the OP's picture, and my 1937 S/42, and another Mauser frame...How do you tell the three apart??? Unreinforced, reinforced, and humped???  |
Richard,
This whole issue goes back to DWM and the 129 mm frame they used. Apparently this frame, at full recoil exposed the rear axle pin and there were cases of it moving and jamming the toggle train. DWM frames have noticeably thinner ears.
Mauser initially remedied the problem by lengthening just the upper part of the frame by 1 mm. Since they were using half finished DWM frames this caused the hump seen on some early K-dates. Thus, they reinforced the DWM frames and caused the hump appearance.
Then as they started using their own forged frames, they just machined the entire frame at 130mm, thus lengthening the frame, hence re-inforced as compared to the DWM frame. But the hump disappeared. This continued until early 1937.
Then, in 1937, about the same time they decided to reduce costs by going to Salt Bluing, they decided to go back to their original thought of just extending the top of the frame to prevent the axle pin from moving; and the hump returned. Maybe it saved a little weight or there was some other reason to go back to their original thought/design to solve the axle pin problem. Who knows??
So, a DWM frame with thin ears is un-reinforced.
The early Mauser P.08s using partially finished DWM frames with the top elongated causing the hump is the reinforcement with a hump. The so called Mauser Hump.
Later in 1934, Mauser built frames with the entire rear of the ears at 130 mm, i.e. a little thicker, is called the reinforced frame.
Then the return in 1937 to machining just the top of the frame to 130mm, are frames with the so called Mauser Hump. Basically this returned to the 1934 solution. This design with the hump remained in place until end of production.
So basically, ALL Mauser made guns had reinforced frames to solve the axle pin problem. But some were uniformly 130mm long (no hump) and some were 130mm long just at the top ( with hump) You can see the hump in post 23.
Sorry for the long message. Hope it helped.
John
PS: Parenthetically, Krieghoff, faced with the same directive, simply machined to 130mm thus thickening the ears and stayed with that solution throughout their entire production. That was their solution to the axle pin problem.