Don't own a Cetme , but a Polytech M14 works fine. I just bought myself a couple 5 shot mags, tried some softpoints for function, and away we went.
Some will say the Cetme cartridge, 7.62 Nato, and .308 Winchester are not the same cartridge. Thats true, and I have no idea how it relates to the mechanics and such of the Cetme.
The Polytech M14 is marked ".308" and has functioned perfectly with everything from Egyption ball to Remington roundnose .308 Winchesters!
The Poly is a heavy beast! Like jmorris say's, a regular rifle is much easier to tote!
Better check the game laws in your state regarding mag capacity and semi-auto's.