Sorry if this is in the wrong forum. I'm thinking of turning my Bushmaster A2 upper into a dedicated 22lr upper. I'd like to remove the 20" barrel and install a 16" 1/12 twist postban barrel and remove the gas tube. It seems like it would be cheaper and more fun to do it myself. What's required? Where's a good place to get a barrel and tools? I have a vise and ability but no specialized tools.