I have a trackfast gun and I usually use the Fpp100 trackfast pins. They are 1" . What is the difference between pins or concrete nails for the trackfast tool. I sometimes have a hard time making the Fpp100 pins hold in concrete blocks will the nails hold better if there is a difference. Will it make a difference if I use a fastener a little longer?

SOURCE: Senco SN4 misfiring intermittently

This is a discontinued tool by Senco but there are still parts available for it. It sound to me that the o rings and possibly the firing valve need to be replaced. I would recommend going to Senco.com and you will find a complete parts diagram in their discontinued tool section. They also have a toll free number if needed and you can talk to their air pro. I have rebuilt quite a few of these and they are not that hard just make sure to clean all the parts and use lube when replacing O rings.

SOURCE: Nail gun problem

This is a bottom fire tool. (NV83A2) You need to hold the trigger down and then as you place the nailer to the wood the safety will depress and it will fire once. This is usually done in one, swift action. If you do this in the opposite way by placing the tool to the wood and then pulling the trigger they often will double fire.