I have a very limited selection of pellets (.22) available locally. I've been using crossman precision max's will decent results. I've had a few pass throughs on some birds and mongoose, where the hit was a solid body shot, but they seem to sometimes have enough in them to make it to cover. Anyways I decided to concave the face of the pellet using a cordless drill/bit, I leave the drill resting on the table and hold the pellet in my hand to center it on the spinning bit, just got to be steady though and gently ease it on to the bit, i've only made 5 to try. Needless to say they are not perfect but not all that bad either. I just tried one 5 mins. ago on a mongoose at about 30yds. away, I hit him behind the shoulder but the angle was really sharp, I seen him roll into the bushes, to my surprise, the was a bunch of "insides" on the outside, as he scrambled deeper into the bush. Normally when I shoot them with a standard, I get pretty clean holes through and though, only when I bust their shoulders or brain them then I have some sort of wreckage. Kinda impressed ATM. If and when I get another shot I may go ahead and do a before and after picture.
