What additional parts would be needed to swap out the factory barrel on a Colt m4 carbine with an ER Shaw .300 ham’r barrel. I don’t want to build a whole new upper, just swap barrels.
I can't speak with first-hand knowledge of the Shaw barrel, or the Colt M4 Carbine, but my Wilson .300 Ham'r barrel has an intermediate-length gas tube. It's not one of the regular carbine, mid, or rifle length gas tubes.
Shaw's website says they use a mid-length gas system for their .300 Ham'r barrels. If your Colt uses a carbine-length gas system, you'll need to swap it out for the Shaw barrel.
Get some magazines too. I believe 350 Legend mags will work. Anyway, you have to remove the front vertical rib from standard plastic 5.56 mags. Wilson sells ready to use mags if you want the easy button.
i shot factory 130gr hot core at first, till i got setup for handloading. they killed fine and was one of bill wilson's favorite hog rounds at the time. since then i've shot most all of their bullets from 110 to 135 grains. i like a bullet until i miss or the hog doesn't go down right away, then i think i need a different bullet, lol
there is an informative thread on thf that has a lot of info. it's too long to go thru, but you can search it for bill wilson's replies. lots of folks ask him questions and he seems happy to respond. i suspect a lot of people pm him too. he will tell you exactly what you need to convert your current ar to a wilson combat ham'r. however, i would think er shaw would be the one to tell you the tube length required for their barrel.