Hello. I purchased an 1909 7.65 x 53 Argentine Mauser a while back. It is all numbers matching and in really nice shape. I went ahead and purchased a set of headspace gauges to make sure it was safe before shooting. I tried the NO GO and the bolt will not close then the GO gauge. That did not close either. Took it to a gun smith (who has been taking a long time with my rifle) and he said he will do a chmber cast to make sure it is the right caliber. Well it was so the other option he suggested would be to replace the barrel. I am no gunsmith, but cannot the chamber possibly be reamed out a bit? Also I have read that there is a place that won't even make these gauges due to the difference of the headspace dimensions of military rifles manufactured early in the century. What would be the best course of action to get this rifle up to spec?
