Ken Waters or perhaps Paul Mathews made up a #1 Ruger for this round many years ago.

I expect whomever chambered up this round, had either Clymer or Manson make the reamer, but I know Pacific can also do this. Personally, I prefer dealing with Dave Kiff at Pacific.

I do not recall the name of the round - Found it - Yipeeee

Designed by Paul- called quite simply, the .37 Rimmed.

His round was not improved, that is, it did not blow out the shoulder of the parent .303 case but merley necked it up with a .415" shoulder, 10 degree 30 minute shoulder angle and .395" neck length. He ran 255gr. bullets up to 2,350fps and 270's at 2,180fps.

This would make a hell of a cool round in an Improved Shaped case.

One of the members here who lives in Alberta built one up on a .45 2.4" case (ie: .45/90 case. This quite literally gave him a similar round to a .375 Chatfield Taylor - if he put in a leade/throat long enough to seat the bullets out an extra 1/10"- a simple accomplishment.

Frank - the .303/.375 IMP (or .375/.303IMP) is a ctg. I've thought about, now and then for a #4 Enfield.

Edited to include: See page 953 in "Jumbo Edition Wildcat Cartridges" - Wolf Pubishing company isbn#1-879356-18-X.