Don, I have a FAQ, that I've meant to post, but just never have, here is the part about Mauser Hump or sometimes called "bump":
quote:
What is a MAUSER BUMP?
Can anyone explain to me the real thinking Mauser had when they produced their early Lugers with the No Mauser hump and then some were intermixed with the Mauser hump and finally all were produced with no Mauser hump?
The early Mauser’s had mixed humps and no humps, but for instance, the Gs seem NOT to be humped, but they all have a thickened back where the hump is to better contain the rear axle pin during the rearward most movement of the receiver forks. The humped Mauser simply had some of the thickened rear frame REMOVED to form the hump.
I have no pictures of the Hump but it is formed at the very rear back of the frame above the lanyard loop. The back of the frame on DWM's is straight up vertical. Some K-dates, G-dates and 1936-S/42 Mauser’s are also straight up or vertical. The Hump causes the rear of the frame to not be vertical, it has a curved appearance to it. You can easily see it from the side. The Mauser Military Lugers are the only ones that have the HUMP, I think! It is interesting Mauser elected to remove that section of metal to return the frame length to the same as a DWM Luger!
Can anyone let me know when Mauser started building the rear frame "bump" to prevent the rear toggle link pin from falling out when the toggle assembly was in its full rear position ?
I have seen some Mauser S/42 coded Lugers without this "bump".
Should this "bump" occur on all Mauser Lugers, i.e. K-dates, G-dates, byf's, Banners, etc. ?
Some K dates had them on them and some Ks had a thickened back edge so if they wanted the HUMP, they could machine metal off the bottom edge of the thickened wall, it was an attempt to keep the rear axle pin from slipping sideways under full recoil. MOST Mauser’s will have it, but they would leave it out for a while then put it back in. Some Navy Lugers approached this problem from a different angle, they made the head of the pin LARGER.
Has anyone ever seen a G-date with a "bump"?
I have never seen or heard of one, and all the data on serial numbers and guns shows none have been recorded. The only possibility in my mind would be a really early G-date in the low "a" block, which would be a transition from the last K-dates. In my mind, there would be a slight possibility of one in this case, but all others I would be very reluctant to believe.
The possibility due to transition brings up the next point. It has been discussed repeatedly here that there was no set pattern as to production and use of parts -- I believe it was stated many times by some that "first in was not necessary first out". -- In my opinion this statement is not correct. There was a transition period with each change and this is when you find the odd configurations -- not before or not after. For instance, the Mauser "bump", or the sharp barrel band, or change from strawed to blued small parts. The 1936 S/42 is a good example of the sharp barrel band. The G-dates all had the sharp barrel band and only the very early 1936's. There is a very short transition period where you find all this -- not thousands of Lugers later. These transition periods show that Lugers were made fairly close to the "first in, first out" concept. Otherwise you would have transition Lugers all throughout the production of each variation, which is just not the case and can be proven as such. Sometimes I get the feeling no one wants to hear about serial numbers or data, but there is still a lot to be learned about Lugers and the different variations, as it is not all in the books as some seem to think, and by recording serial numbers and their characteristics, we can record these transitions and improve our knowledge. I would encourage all when posting to give the entire serial number of their Luger, as it is important for data and for correct information.
I remember that in the 1930s Mauser added metal to the back of the frame in the area of the rear toggle pin in what is sometimes called the Mauser bump. Presumably that "bump" was to prevent this rear toggle pin from coming out during firing.
