I used to use gamo lead ball ammo in my P99 compact but you had to sit and sort a tin first as they were all different sizes. I would get half a tin of useable ammo out of a tin. Then one of the guys in the club gave me some shotgun shot I think it's number 12 and it's great for bb pistols so try to get some of that.
Bill
AA S200T 10m , HW100T, Cometa 220, Diana 27, Original Mod 6, Gamo compact+center, Rohm twinmaster Top, S&W 586/4+6+8, Berretta 92 airsoft, Blinged crossman 2240, CP88 4", CO2 Uzi 6mm, Air arms Alfa proj .177, Drulov DU10 .177, HW 99s, Hammarelli AP20pro