It is completely legal and they will not give you trouble on those items.
"Do you have anything to declare?"
"Yes I bought a tactical vest and camo, and some great porn and a bottle of bourbon"
"Whats the vest and camo for, and whats the total value of goods?"
"I play airsoft/paintball/whatever and value is [insert number below the personal exemption for however many days you're there]"
Done. The worst that happens is the agent asks you what it's for and if you respond truthfully, you're golden.
Views are my own.