i have a .30 cal, i thought the .50 was a little too big, and i was goin to put both but then i didn't like the "mini roadking" look it had LOL!
i just drilled holes through the box and fender, couple of o rings for water sealing, i could just unscrew it if i want to take it off(i had a can of dew explode in it SO being watertight it didn't go anywhere lol, took it off to clean out)
looking back, i didn't even measure where the holes were going, i kinda just eyeballed them on the box, then the fender lol lucky it worked!
this is an old pic btw, almost everything is flat black now, including the handlebars as of yesterday lol