Welcome to the Fire!!
Mickey Coleman built me a 25-204 on a M700 to my specs, with the help of Erich. I love it. I only load 80 Gr. TTSX and 75 Gr VMAX. 3,000 fps is plenty good for me. Feeds perfectly with the factory box and follower.
I did the old Campfire trick on the ADL mag box - remove the factory spacer and screw in some .25" aluminum bar stock. Can't remember what COL I'm loading, but it gives me plenty.
I also have a 6mm/223 (Steelhead here had it built by IT&D) and love it equally. Not sure of the velocity, but I only load 105 AMAX and it has the same mag box mod.
