FMJ's will likely preserve the pelt better but shot placement is a bit more critical with non expanding ammo. The FMJ will more than likely exit, in fact i'd say that there's a 99.99% chance that the FMJ's will exit so be aware of that. FMJ's don't 'dump' a lot of energy into the target so if this is purely for 'pest control' expanding ammo would likely be the better choice. If you're hunting for pelts the FMJ is likely the better option because your exit wounds will be about .30 cal, where as, soft point ammo could easily leave a soft ball sized exit hole.