.300 WSM — SAAMI's maximum case dimensions

[Ken Howell]

Just got the SAAMI drawings for the .300 Winchester Short Magnum case and chamber.

Here are the maximum CASE dimensions. Chamber dimensions, of course, are altogether different.

rim diameter (Ø) — 0.535 inch

base Ø at 0.200 inch from breech reference line (BRL) — 0.5550 inch

shoulder Ø at 1.664 inches from BRL — 0.5381 inch (angle 35º)

neck Ø at 1.8021 inches from BRL — 0.3440 inch

mouth Ø at 2.100 inches from BRL — 0.3440 inch

cartridge over-all length 2.56 to 2.86 inches

 

[danr55]

Well, they didn't exactly start with anyone elses brass, but they didn't stray too far. The dimensions given are all within about .010 inches of the 404 Rimless, Nitro Express. Regardless, they did not take the 404 Jeffreys and shorten it. They did a few other things also. Ken, this is good info. I can start with this and play my 6.5 game with it. This may turn out quite nicely. Thanks for the info.

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Dan AZ www.huntandlodge.com