Montana Man has given you a good assessment--most likely you have a "light-strike" issue going on there.
WW primers are fairly soft, so even more likely it is so.
i usually recommend Federal primers for pocket rigs--due to their low hammer mass issues, smaller springs, etc., and ultra soft primers provide some degree of mitigation for those issues.
a tired hammer spring, or a tired firing pin spring are a couple of the potential gremlins in this situation.
(just as an aside, pocket rigs are prone to getting packed with lint, and they should be dismantled regularly, and wiped clean of debris).
i've used numerous Kel-Tecs over the years, and have a lot of experience with them--in my opinion and experience, they are not built nearly as well as the Rugers, but on the other hand, they are not the "poor quality, bottom of the barrel" rigs some would have you to believe...
bottom line--know your rig and work with it/use it often...
