Hi DarylS,

Yes, it certainly muddies the water but that is not unusual for this cartridge.

I believe that at one time, both Western and Rem Peters made a cartridge which fitted both the Mauser 9x57 and the 9x56 MS.

The 9x56MS seems to have a wider variation in cases, chambers and bores than most.

Bores in good condition seem to range from.352" to .358".

Some chambers will not accept cases larger than .464" at the web others will accept them at .468".

All the British proofs I have seen photos of have 2.22" case length, but mine will not accept this length, so I trim to 2.216"

Interestingly, there is also a range of British proofs on 9x56MS rifles, I have seen photos of the following:
- 31gns cordite x 245 max (one in South Africa and also mine)
- 35gns cordite x 250 max
- 35gns cordite x 232 max and
- 46.5gns NC x 245 max.

Also, even reputable reference books show a variation in cartridge dimensions and bullet diameters.

What is a MUST with rifles in this calibre, is to slug the bore and test different cases until you find ones that fit. I had to wrap the cases at one spot with cello tape, lube then FLS to get them to fit, once fired they were fine.

What is critical is the loaded neck OD, make sure that a bullet will slip fit into a fired case. Mine must be < .380".

Challenges make life interesting and the 9x56MS is certainly an interesting cartridge.

Looking forward to copies of those articles.

Fraser