Fx impact

The skirts dont necessarily have to be bent. The problem is that sometimes, the material is not as dense in one spot as it is in the other one. I believe that due to their shape, pellets are pressed and not cast - sometimes there the lead has some rubbish in it - or sometimes... there is always a bit ot it. After all its just 99% or 99.5% lead or let it be 99.9% - but the rest is just random material. If you have ever cast bullets you certainly now how much crap you have to skim off even when you use over 99% refined lead. Now imagine how much of this poop is left in the lead. So you can get spots that are less dense in one point than they are on the other side of the head/skirt.

You can also see that skirts sometimes are not perfectly even in thickness. Maybe the die was misaligned by just a thousandth of an inch. So when the pellet leaves the barrel with its spin out of the grooves, the heavier point in the head / skirt tends to want to go outwards due to its centifugal force and you get this elongated helix. Its annoying but there is absolutely nothing one can do about it.

I think its always a perfect coincidence when you get this super rare tin of "magic pellets" that will shoot lights out. Absolutely perfect die alignment and very little crap in the lead...

Just my .02