That is very interesting. I was shooting a 45-70 with hornady leverevolution factory loads at thick cardboard and the jacket never made it through. They would probably perform differently on an animal. Nevertheless it is interesting how they perform after going through something hard compared to...
I clean when my groups start opening up. I find it unnecessary to clean if it is still shooting straight. This is usually past 100 rounds for me. If the rifle needed to be cleaned after around 20 shots I would sell the gun.
The 6.5x55 would be my choice. With the 156-160gr bullets it is very effective on moose, elk and bear. The 130-140 gr bullets are very effective on deer sized game. With the high b.c. of 6.5 bullets they are very good at long range.