Cartridges

[RCS]

I do not think the Mauser Express cartridges were ever as popular as the British Express cartridges were for hunting big game. Also more difficult to locate for the collector too.
The large Mauser square bridge bolt action rifles were imported to the USA late 1920's into the 30's but expensive. The surplus Model 1917 Enfields or Model 30 Remingtons were used for large caliber custom rifles.

Small bore cartridges outside of the USA:

The 222 rimmed from Australia appeared in the 1960's, perfect for the Martini Cadet actions.
although I once rebarreled a Martini Cadet to 218 Bee which worked out. The 222R will fire a 45gr bullet at 3450 fps.

5.6x61 Vom Hofe also rimmed, introduced in Germany 1937 and re-introduced in 1962 will fire a 77 gr bullet at 3700 fps.

244 H&H uses the 375 H&H necked down introduced in 1955 in custom bolt action rifles in Scotland. will fire a 100 gr bullet at 3500 fps

5,6x57 RWS first appeared around 1964 with a 50 gr bullet at 3900 fps. Also difficult to locate cartridges in the USA