It was one of those rainy days,when most people are in bed ,but the deer where moving I was in a tree stand an I shot at 3 different bucks that morning an must have missed every one,no signs of being hit,no blood and no hair on the ground.They were about 40 yards off.I was thinking my gun was off,when a buck comes off a ridge and I down him at 125 yards.I think I missed the first 3 deer because of the steep angle of the shot.If you hit a deer and there is no blood,there will be hair on the ground close by.Sometimes when you hit a deer high up in the chest,you don't have much of a blood trail,they more or less bleed out inside.When you have some time to practice,I would test your old pellets against some new ones and see if you have the same point of impact,that should give you an idea if your pellets have weaken with age.I usually shoot 300 grain bullets.This year I shot one deer kinda facing me.I found the bullet under the skin at the hind quarter,it didn't expand,but it dropped the deer in its tracks.