Nails don't go all the way through? - Dewalt 1 - 1/4 - 2 - 1/2" 15 - GAUGE 34 Degree Angled Finish Nailer Kit

sounds like your firing pin may be bent

I have the same staplegun. Are you sure it shoots nails? If it does I don't know it and have had mine a long time.

I don't have that same model but my gun started doing something similar a while back. I was able to disassemble the head of the gun and found that the hammer or piston that drives the nail had rounded itself off and wasn't able to make good contact with the nail head. Instead it pushed itself on top of the nail and got wedged. It's nearly impossible to see the stuck nail or dulled piston head without taking it apart. Hopefully this will help.

A close inspection around the outlet area may reveal a piece on "nail-head", or other fragment causing the new nails to lean slightly. There could even be an entire smaller nail crammed into the area just forward of the nail exit (or just to the side). If I were you I'd get it in bright light, where I can sit and take my time, and with magnifying glasses (unless you have 20-20) use a small tool and inspect closely.

I have had this happen to me and I thought, "well there's not all that much place to hide"... And I didn't see it the first time I looked. But sure enough, there was an entire nail lodged in there in such a way that I thought it was part of the nail gun the first time! Good luck.

Oh, give it a liberal oiling while your at it.
Don

If the driver is not returning to top of cylinder, the nails will not feed into position. Remove nails from the gun and Insert thin tool into nose to verify that the driver is all the way up. If the driver is already at the top of the cylinder, then nails are not feeding correctly (check for debris in rails or for proper nails). If the driver was not all the way up, check for bent driver blade, loose or too tight piston ring or restriction in the headvalve (upper bumper cracked). Good luck

Assuming that the nails are moving ok down the rails and the pusher is in good order, if the driver does not return to the top position, the nails will not move into position. Remove air line to gun. Use metal rod to push driver to top position and verify that nails move into position. If the driver was at the top position, check for debris in rails or wrong nails. Place a strip of nails on the outside of the rails and align the nail heads with the rails. The first nail should align with the path of the driver. If the first nail head is tilted back away from the path of the driver, the driver will just push nails back into the rails and slip past. If nails are correct and driver does not return to top, suspect worn piston oring or cracked lower bumper or lack of lubrication.

There are two ways dependent upon the gun model. Pull the charging handle back and insert the nail clip with the forward facing, leading edge POINT in first. Some guns allow you to put the nail clip(RACK) in the gun then pull back on the charging handle. BOOM your ready to shoot.

It may already have a nail jammed in it. You may have to take off the front face that holds the firing pin. There should be one or two screws in front just above where the nails come out. If you remove these there will be a plate that comes off and then you can remove a jammed nail. Look first to see if there is a jam before doing this. Also maybe you have the wrong guage nails or maybe you don't have proper air pressure. Hope this helps.

I ran into this problem many times. Don`t use the Bostitch brand nails. Use the generic or other name brand. You`ll notice the generic one`s heads are just a little bigger and the driver blade won`t run down the side of the nail!
Thanks,
Jeff