OAL is just a reference as it varies slightly from gun to gun, barrel to barrel. the best way to determine the OAL for your gun is a "drop-in" test.
load a dummy round long, take out your barrel and drop it in. the cartridge will not turn freely. and then adjust the seating to shorten the cartridge, little by little until the butt sits almost flush with the barrel mouth and can turn freely in the barrel.
that's your OAL. it should fall in the min/max range of the SAAMI standard(free pdf download online). then you are set. and don't be alerted if you get slightly different length from cartridge to cartridge if you are on a progressive press because due to the different situation at different station, the pressure on sizing could vary a little. as long as it's within the limit and fit the drop-in test, you are good.