How can you tell if the M39 is talking the 53r, or 54r? from outside?
I tried chambering 54r brass in my M39 and you can very faintly see markings on the outside of the case rim where the brass came into contact with the rifling grooves. This leads me to believe that the chamber is slightly smaller than your standard 54r mosin.
Although everything I've read seems to indicate that you should have no problem firing 54r in a 53r chambered rifle. You might just have issues with closing the bolt on some rounds, but they are otherwise interchangeable.
Thanks. I was always wondering does the small difference like 0.5mm will make big difference to the chambering? what will be the production tolerance then. Why Russian made 0.311 the bullet size as compare to well settled .308? So intruders will not be able to use the captured bullets? They are totally different anway, 308 54r will not fit into 308 Win.
I tried chambering 54r brass in my M39 and you can very faintly see markings on the outside of the case rim where the brass came into contact with the rifling grooves. This leads me to believe that the chamber is slightly smaller than your standard 54r mosin.
Although everything I've read seems to indicate that you should have no problem firing 54r in a 53r chambered rifle. You might just have issues with closing the bolt on some rounds, but they are otherwise interchangeable.
In a rifle's chamber, in front of the end of the case mouth, there is a smoothbore section, and then the rifling starts. There in no way that a cartridge case can touch the rifling. Are you seeing the remains of the crimp?