buy the best paint you can that will go through it, nothing more frustrating than hitting someone with the one or two shots you have only to have it bounce. I got someone on the lens with my pump last Sunday - bounced, his shot back broke on my neck - that's the last time I buy cheap paint!
Not for a pistol. It needs to be a balance of being able to break and not squishing in the mag. I tend to find 2* / silver grade stuff works, I tried gold in a 8 ball mag for tpx and it squished them into a pile of poo. You can off course cut tension out of the mag spring. Its a fine balance as we all know paint changes batch to batch. I tend to find someone using something that looks good for a pistol and get a handfull off them. Winter paints good but doesnt always break at distance . .a pistols not for distance really though.
@Ninjabreadman get a pump gun mate, you'd love it. Tippmann Sl68ii is what ive used for years