ive heard this around and i have experienced it myself and thought i should point this out so people know.
the whinchester 7.62x54r rounds that is softpoint and has 180 grain has some issues
ive noticed when firing this the rear of every 6th bullet blows off and the charge metal will get stuck in the BOLT, if you notice a hole in the rear of your casing, take bolt apart and clean, then gap the pin using the tool that comes with the mosin.
the reason as some have pointed out is due to the inconsistent quality of the Winchester version. i find this bullet to not be reliable or consistent personally. but its up to you, i find them overly expensive and just not worth the price(fun to shoot milk jugs filled with colored water)
now ive never had issues withe surplus (windex or hopps the barrel after), they are less accurate
now the brand i do approve of is the brown bear(my m1a loves this brand too) version of the 7.62x54r, this brand offer the same style as Winchester also a silver bear which is non re-loadable (i like these cause the range guys jack my brass)
now i can pick up the brown bear for 10 bucks with 20 rounds, soft point and everything (hell they have various grain size too)(midway USA)
Winchester is 27.99$ at big five for 20 rounds
twice the price half the quality.
now my mosin is choosy in rounds that are consistent (don't know your preference) i have used brown bear, surplus , whinchester ect
various sites for ammo