My longest is a 1943 Izshevsk Mosin-Nagant 91/30 with rubber recoil pad butt extension and Uncle Mike's slip-on recoil pad.
Its overall length is 50 1/2" and it has a 15 1/2" LOP, which fits my 6' 5 1/2" frame rather well.
I have two more that have only the slip-on pad, their OAL is 49 1/", LOP 14 1/2" and this LOP is appropriate for my teenaged Grandkiddos.
The original, unmodified rifle's OAL is 48 1/2", with a 13 1/2" LOP, which was, one assumes, adopted to be appropriate for Russian conscripts wearing thick Winter clothing somewhere in Siberia.
Removing the slip-on pad allows the rifle to be shortened a bit more than an inch for fitting it into a case.
Greg