I'm trying to staple carpet to a 4x4 piece of wood to make a scratching
post for my cats. The staples are 1/2" (12mm) and I'm having trouble
getting them all the way into the wood. They don't seem to go all the
way in and they're easy to pull out of the carpet and wood (too short).
Also, one side of the staple keeps bending everytime which I suspect
may be part of the problem. Here's a picture of the bent staple -
www.geocities.com/littleboyblu87/staples1.jpg

What am I doing wrong? Do I need longer staples? The only other size
staple is 9/16 (14 mm). Or is the problem that I need to use more
strength/force to get that staple in?

Last year, I used another staple gun to do the same thing and I had no
problems. But I may have used longer staples. Or maybe that staple gun
is better than the one I'm currently using.

Just in case anyone wants to know, the staple gun I'm using is the
Stanley Heavy Duty Staple and Nail Gun - Model TR250.