I've been perusing websites and catalogues and observing manufacturers who publish a chambering of 450-400 for newly built rifles.

I did, however have a sudden thought;

I've been assuming these are all the 3" version, but there is of course the possibility that at some of these manufacturers may be producing riles in 3 1/4" or some other variation.

Have I been correct in assuming the 3" or have I been leading myself down the garden path?