Don't pin/weld a suppressor to a 10" barrel unless you have two suppressors. You'll want to use that thing on every gun you own. Open a trust first, then apply for your stamp. Been down that Form1 road.
Build what you want. Nobody is going to do it for you... 223 is boring but works. 300blk is cheap and loves cast boolits. 6.5 Grendel is exotic, sexy, and ballistically superior. 450 Bush is big but indexes off the case mouth. Same problem for 350 Legend. 300 Hamr, 458 Socom, and 6.8 SPC are great but with a small following in the tacticool crowd. Shame.
Animals are rarely killed past 200 yards.
I've taken quite a few deer with proper, handloaded 223 under 100 yards using Speer 70gr and Sierra 65gr. Don't use Barnes bullets in 223 for deer. They pencil right through even though they expand.
I have no doubts the 300Blk would work great at the same ranges with a wider variety of bullets. But whatever you do, don't shoot elk with a 300Blk. Poor thing deserves better.