In response to KWJohnston's observation that he had seen a Fraser marked as "303" but had a standard rimless cartridge-style box magazine:

.303” Mauser (7.65mm Fraser)

The rimless case of this cartridge was the same as that of the 7.65 x 53 mm Belgian Mauser cartridge, with a length of 2.080” - 2.100”, and the round had a bullet diameter of .311”. The case was stamped 7.65 mm ELEY and was produced for the firm of Daniel Fraser in Edinburgh. Fraser loaded the case with his patented oblique ratchet soft-nose bullet. (Fleming; 30, 31, 206; Hoyem; 144, 213)

http://www.acant.org.au/Articles/Other303Cartridges.html

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