Slugs in a regular barrel

So I've been looking around trying to find some slugs that might do well im my Beeman Commander. It's a pretty cheap gun but I'd like to make them work and fool around with them if I can. Im aware of barrel diameters and slug weights and that guns can be super picky. From what I've seen Fx Hybrids seem like a good option but really costly. The H&N sample pack looks pretty good too. I really want to get ahold of some NSA slugs but I can't find a sample pack anywhere that doesn't charge $30 and up for shipping. Any suggestions for other slugs? Does anyone know where I can find a NSA .22 sample pack?