doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com 70 mm ammo in 67 mm chambers?

I would expect the pressure increase due to the shorter chamber to be slight. I am more concerned about the pressure of the load. I would be quite surprised if anything on your gun broke or bulged. However, I'd avoid a steady diet as I would expect accelerated wear. A few a year probably won't hurt anything. Note, however, that Sauer guns do have a reputation for robustness and this advice is not for all guns.

Rocketman,

Thanks! This gun is NITRO proofed, of about 1920 vintage +/- a few years, with same proof stamps as my Merkel, which is pre 1935. Do you or anyone here happen to know what that equates to in PSI or modern CIP? I have always taken these vintage german proof stamps to equate pretty much to modern CIP.

Thanks,
Niklas

I think CIP would be safe, for sure. However, SAAMI limits are higher than CIP - caution on SAAMI shells. I'd worry about the wood as much as the metal.

Thanks Rocketman,

The 16X70 mm Federal and Winchester ( latter made in Australia and Italia) shotshells I would most likely buy and use, when I do not have my own reloads, are known to have chamber pressures below CIP max two of three times tested in independent lab. Even highest chamber pressures are similar to some brands of European and British 67 and 65 mm CIP loads intended for use in 16X65 and 16X67 guns.

So far, on my other German and all my Swedish hammer doubles, wood has held up nicely to few thousands of 24 gram loads and hundreds of 28-32 gram hunting loads at 1200-1250 fps. May that continue.

Thanks,
Niklas