Chamber Min-Max variation?

[Ray B]

Recently I had occasion to compare the fired cases of three somewhat vintage but well cared for rifles, all chambered for 257 Roberts. The oldest was a Remington Model 30S from 1935, followed by two Winchester Model 70s, 1938 and 1949. The Remington has by far the largest chamber. Cases fired in it then with only neck sizing won't chamber in either M70. The case can be pushed into the chamber but significant resistance is met when trying to turn the bolt handle down. The bolt can be turned just enough to disengage the sear from the bolt but anything further would require a mallet. The tightest chamber is the 1949 M70. Slight resistance is felt when chambering fresh factory ammo in the 1949 M70. Factory ammo in the 1938 M70 feels just snug on the last bit of bolt turn. Factory ammo in the M30S is as if it isn't there- the bolt pushes the cartridge into the chamber and turns down not unlike the same movements with an empty chamber.

Cases from the 30S do not appear to have stretching problems as a case can be fired, neck sized, loaded and refired several times (with moderate loads) until the case fails due to splits at the neck. The main issue is that cases from the Winchesters are not mixed with the Remingtons, and it is best if all three rifles have cases that are specific to each rifle.

I'm wondering if such a spread in chamber size is within standards of tolerances or were things a little more variable 80 years ago.

 

[nztimb]

Not unusual for factory rifles as the reamer dulls and is sharpened so it makes for marginally tighter chambers. It is always best to keep brass seperate for each rifle unless you are FLS every case every time

 

[Shootist43]

I totally agree with Von Gruff. If you have multiple rifles in a given caliber than you need to keep the cases separated or Full Length resize to get them to work.