All gunshops need to run background checks for firearms purchases. Unless you have a C&R or FFL. The Powderhorn probably has some of the best prices and selection in the area. I used to work at the Powderhorn. But there are others:
B&J's on Industrial ave, Williston. (way over priced, not very flexible)
Midstate Sports, rte 7 Ferrisburg?. ( not the most pleasant of owners to deal with, but fair.)
Bobs Gunshop, Georgia. (Well, Lets just say his name should be Dick)
Dave Pidgeons, Rte 7 Middlebury. (Provides gunsmith services as well, hard to deal with at times.)
Alder run, Franklin. (competetive with the Powderhorn in prices, but way out in the sticks, has a nice gun range.)
Parro's Gunshop, Waterbury.(Class 3 dealer, Good selection, priced reasonably)
Datillios, Shelburne rd, So Burlington. ( Jimmy is a good guy, good prices, crappy selection, no display area to look at stuff)
John's Gunshop, Morrisville. (good people, good prices, but very religious and sometimes pushy about it to new customers.)
There are others, But those are just off the top of my head.