Hello holo07
I assume you know the Trapmaster is CO2 powered.
It requires 2, 12 gram cartridges.
The ammo is lead or bismuth shot (usually # 8) loaded into Crosman plastic shells.
You can find preloaded shells on eBay
Here's a link to a current auction, ending Monday
https://www.ebay.com/itm/255038789148?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649 Every so often Baker Air Guns has a box of 100 preloaded shells on sale. Last price was $75 plus shipping (ouch!)
You can also buy empty shells (plastic or aluminum) and load shot yourself
To do so you will need shot, shells, & wads
You will find examples of these on eBay also
Regarding led balls
I've shot .375 lead balls
Available from Track of the Wolf
https://www.trackofthewolf.com/?p=BALL-375 I put them into the plastic shot shells for loading so that they do not roll out of the barrel
Hope this helps
Enjoy the Trapmaster
FWIW
Mine is a starling annihilator at 12 yards and under
Ed