I used K&N Match Kugeln in mine, it loved them, actully all my Umarex Pistol like them.
WildBill as a Umarex owner why don't you join the UBC (Umarex Boys Club) and join in our pistol Comp, all i need is your first name and a tag line. (Look at Gang thread below)
http://www.airgunbbs.com/forums/showthread.php?t=268048
atvb
Jason