Chambering Problems

Sieger · 11-07-2003, 02:46 PM

<blockquote>quote:<hr />Originally posted by unspellable:
Johnny, the cartridge does not headspave on the step. The step is 14.1 mm from the breech face while the headspace is 19.1 mm at the step between the end of the chamber and the beginning of the barrel. A point to note is the SAAMI max case length is 19.15 mm, another point of discrepancy.

So I am still wondering if they went to the straight tapered case but retained the original bottle necked chamber. The bottle neck was very slight.

At the risk of being called an iconoclast, I have a theory that the 9 mm round was developed directly from the 7.65 Borchardt/7.63 Mauser case without the 7.65 Parabellum case being involved, as opposed to the more usual theory that the 9 mm is a necked up 7.65 Parabellum case.<hr /></blockquote>Dear Unspellable:

I just read last week that there were two reamers involved in the chambering process. Why this was done...?

Well, the practice persisted from 1902 through 1942 so the German Engineers must have had a good reason for it.

For the origins of the 9mm casing, study Luger's 480 and 480A casings, as these were, indeed, bottle neck 9mms.

Sieger

11-07-2003, 02:46 PM	#27
Sieger User Join Date: Jul 2003 Location: New York, NY Posts: 1,579 Thanks: 2,144 Thanked 402 Times in 251 Posts	</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by unspellable: <strong>Johnny, the cartridge does not headspave on the step. The step is 14.1 mm from the breech face while the headspace is 19.1 mm at the step between the end of the chamber and the beginning of the barrel. A point to note is the SAAMI max case length is 19.15 mm, another point of discrepancy. So I am still wondering if they went to the straight tapered case but retained the original bottle necked chamber. The bottle neck was very slight. At the risk of being called an iconoclast, I have a theory that the 9 mm round was developed directly from the 7.65 Borchardt/7.63 Mauser case without the 7.65 Parabellum case being involved, as opposed to the more usual theory that the 9 mm is a necked up 7.65 Parabellum case.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Dear Unspellable: I just read last week that there were two reamers involved in the chambering process. Why this was done...? Well, the practice persisted from 1902 through 1942 so the German Engineers must have had a good reason for it. For the origins of the 9mm casing, study Luger's 480 and 480A casings, as these were, indeed, bottle neck 9mms. Sieger