Need some help with a measurement

[Marauder 1]

I need some help from you guys with M19/30's with the original barrels. I need to get the measurement from the front of the receiver (where the barrel and receiver come together to the rear site pivot pin. It appears there is quite a variation across years.

If you guys would like to take part in this experiment here is the info I need

Arsenal
Year
Measurement as stated above
and if it's a standard M91/30 or a Sniper or Ex Sniper

If you guys would help with this I think I might be able to see if there is a pattern.

Thanks
Mark

[AssassinBean]

Izhevsk
1938
5.25"
Standard M91/30

[Gamecock24]

My '37 Tula measures 5.302"

[b0neZ]

Tula
1938
5.125"
Standard 91/30

[Marauder 1]

Any more? I would like to get a large set of numbers for a reference

Thanks
Mark

[iridium-192]

5.277"
1942
Izhevsk
standard m91/30