I have observed at least four different action types on these PH Mausers. Early ones used reworked '98 military type actions. I assume Spanish origin. The next three types were Spanish made variants of the FN style action. The first used a receiver with the internal breeching collar, with only one cut for the extractor. C style collar. The left hand bolt lugway stops before the collar. The bolt has elongated gas vents, and the firing pin shoulder engages one of the cuts as a mechanical block against discharge when partially locked. The second has a similar bolt, but the left hand lugway is cut right through the collar for ease of manufacture. The third style has no internal collar, round gas ports on the bolt, and the shoulder on the firing pin is simple and round like a '93 Mauser, and the bolt stop/ejector is the abortion from the Midland rifle, secured by a single Allen head screw. The best features of the '98 Mauser were eliminated in this last version in the interest of economy.
Frequently one can see a little grind mark on the left side of the receiver tang, where the "Spain" was ground out.
Invariably stocks are Italian, made by Sile. Trigger guard/magazine assemblies are PH diecastings, and the triggers are PH commercials. Metal polish and bluing are superior. Never saw one with a chromed bolt; usually finely polished. Some were blued.
Never cared much for the detachable magazine conversion used on the C models. Best that can be said is that the magazine is detachable, for those who prefer this.
s for the info - there is not another mark on the barrel or reciever ! You are right there is a square sign after the 19.5 tons - nothing else ! Does ser # not help in a ph case ? RJ 
