I'm not sure how much manufacturing Browning actually does in Utah, they have a factory outlet store in Morgan (Up the canyon from Ogden,) but I don't know if they make apparel, bows, firearms, or what. I will settle for giving Utah a chunk of credit for Browning's designs. (I met Val Browning a couple of times before he died, great guy and big philanthropist, there are college buildings all over the state named after him.)
You guys named North American Arms, but I also can think of LAR (as in Grizzly), Black Rain Ordnance, Barnes Bullets (factory off the I-15 in Nephi, recently acquired by Cerebrus, or however you spell it,) and ATK Thiokol. Now that the NASA budget is on indefinite hold, ammo might become their biggest business. (Or might be already, what the heck to I know?)