PP, I beg to differ that Mosins are in a class by themselves. In a friendly manner of course.
IMHO, rimmed cartridges are in a class all by themselves but are all very much alike.
There is a member on this board that goes by the alias of smellie. His pet peeve is the misunderstanding of head space in Lee Enfields. He could and probably should elaborate more on the subject and include all rimmed firearms.
Any cartridge with a rim, has a notorious habit of not matching the rim thickness of the cartridge next to it. Even out of the same batch. Start mixing factories, countries of origin war time specs, peace time specs and it all goes down the toilet.
The only thing that may be a cause of concern in a rifle that shoots rimmed cartridges is wear on the lugs and the seats they fit into. When the seats set back or the lugs compress or wear then a dangerous situation can be encountered.
That was one of the appeals of the rimmed cartridge and why it continued in service for over 100 years. You just didn't have to be that careful with head space issues. To tell the truth, most military rifles have generous chambers that wouldn't even be considered acceptable on today's commercial offerings.
You know as well as I do that there is no way that one size fits all can be any sort of a standard to go by. The good thing is, most nations did follow a modicum quality control but during wartime extingencies, they pushed the limits to the extreme.
I have a 1942 dated No4 MkI* Long Branch with a 2 groove barrel that I purchased in 1963, new in the grease out of the basement of the Hudsons Bay store in Vernon. It cost me the princely sum of $5 and came with a 50 round box of surplus ammunition "to get the kid started". I was 12 years old and the money came from a ridiculously long paper route. Anyway before I run off at the keyboard, I took the rifle, cleaned all of the cosmolene out of it and shot it. Big problem, I didn't realise that you had to clean the cosmo out of the bolt as well. Luckily a neighbour that had spent a lot of time curled up with one during WWII, took me under his wing and showed me how to take care of it. He also explained about corrosive ammuniton.
That rifle, which I still own shoots very well. The bolt head is a number 3 and it closes easily on the Max field gauge. What can I say. It was shipped from the factory this way. Everything on it has matching numbers that should have numbers, including the stock. Winchester Mod 94s are the same and so are the Model 95s in 30-40 Krag. The 6.5 Romanian Mannlicher I have is similar and if you ever want to see a real nightmare of rim thicknesses I think it beats the pack.
IMHO, we make way to much fuss over head space, even in rifles with rimless cartridges.
