Forums.NitroExpress.com

Sure you can check the data for the 7.65 and the 9X57 on the CIP site.
The standard pressure for the 9X57 is a good bit lower than the 7.65.
In many ways the 9X57 is a better deal since it is based on the 8X57 case. The 8X57 brass is more common and there are known standards for the headspace gauges. Good luck figuring out the dimensions
for a 7.65 No Go Gauge. The 7.65 has something CIP calls the delta L problem. With the delta L problem the longest possible cartridge is longer than the minimum chamber. The delta L is not listed in the English drawing but it is listed on the German language CIP drawing.
I put together a little spreadsheet to calculate the "headspace" and cartridge length dimensions using a .375 datum circle for the 7.65. I found that there is a delta L but it is different than what CIP shows. All in all the 9X57 is a better deal.

7.65 page

http://www.cip-bobp.org/homologation/en/tdcc_public?page=3&cartridge_type_id=1

9X57 page

http://www.cip-bobp.org/homologation/en/tdcc_public?page=4&cartridge_type_id=1

Edited by Ireload2 (04/04/15 07:47 PM)

Post Extras