I use 8 x 11 MM leads and I knock a fare bit of game over on a regular basis I hit squirrels behind the front leg and they drop but with steel ball bearings the just run off if you don't hit them bang on and lead you can make your self
I wouldent dive straight in with a ppsg mate you will only regret it when you fork hit lol I have some ttf cattys here multiplex it's bomb proof I'm selling them £20 banded and posted to any were in the UK if you wanna try ttf it's how I started
I used to shoot a natural mate the I switched to ttf and my accuracy has increased and my first hunt with a ttf catty got me 9 squirrels so I'm pretty sure I'm gonna stay ttf so yea it dose increase your accuracy some times