Hello Felixx
At least with my Rivet Tool, i think that the problem u are having is that u are not usingthe right size rivet tip on your rivet tool, ( theses are the 3 tips that are on the side of your rivet tool) u need to use the same size tip for the rivet stem. Sizes tips on mine are 2.4, 3.2, 4.0, 4.8 and so on. so try to use the same tip with the same stem. after 2-3 practic rivets and notice this it was great, Stem shoots out almost like if it were a ejection chamber.
oh one other thing to, what rivets u use, Down here there are only 2 type Aluminium and Steel ( not steel but thats what its called) if your rivet tool is not a Pro tool i would uses the Aluminium. >The Steel are harder to place even if it is a pro.
Thats my 2 pesos hope it helps, but i would pm Matt 16 yrs is 16 yrs