.30-40 Kragicon will also work, being VERY similar in shape and size to .303.

After I finish my "L-41 1/2", the next little project looks like it will involve raiding the "spares" boxes to cobble together a No5 style carbine (No4 Body) in 6.5 x 53R (Dutch / Romanian rimmed version of the classic 6.5 x 54MS). Rim and general case are very similar to .303. Should be a neat little "field" rifle.