I recommend the above mention of the bore hole size - 1.5" - for barrel vise. I managed to buy a length of 1.5" diameter aluminum round bar and cut to 1.5" lengths to make the barrel vise inserts on my lathe. My miter saw with 60 tooth carbide blade seems to slice the 6061 aluminum easily. Biggest barrel that I have fitted are for M1917 / P14 - about 1.290 at the fat end of their barrel, made tapered inserts - so not much "insert" thickness, even with a 1.5" bore hole in the vise. I have another four bolt barrel vise here that appears home made - 1.75" bore, but I have not yet found aluminum stock to make that size insert, nor have I needed it. I found that a dusting of rosin, and a wrap of computer printer paper completely eliminate any aluminum scuff marks on the barrels.
For action wrench, I ended up with the Brownells system - probably 10 or more "heads" for various actions. Also have one internal wrench - a "spade" wrench, I suppose. I prefer to use that one to tighten up a receiver, rather than break it loose. Had to make a tall "jack stand" for outboard end of socket - hard to keep that long internal "spade" wrench straight with action / barrel when leaning into it with a 18" strong-arm, often with a 3 foot pipe over it as a snipe.