Tinker,

Martinis were made in 303 and issued as police rifles in India in the past. For a long time, the British armed the police with either Martini 303s or, later, with SMLEs with a sealed magazine so that they were converted to single shot as India policemen in the Raj days had a reputation for trigger-happiness.

I am looking at a deluxe Martini in 303 that a member on these forums has suggested to me - it is not in the USA but it is a supremely beautiful rifle and worth the paperwork for importing it here.

Do let us know how your rifle turns out.

Good hunting!