AbitNutz,

I have not had my actions barreled for the 303 yet, but I did try cycling 303 ammo through the actions alone, and had no issue at all. It was almost as if the action had been made for the 303. I also know a friend who has a Siamese built into 30-40 Krag, and it shoots and feeds brilliantly as well. So there are possibilities . . .