Left the 300 Blackout camp....
I briefly took a trip into the 300 Blackout. I loved it, BUT ammo is totally unaffordable. Even reloading cost 3X to 4X more at least than 5.56. Correct bullets cost about $200 or more for 500 - when you can even find them. I found I almost stopped plinking when I made the switch, because I didn't know when I could afford to load more at .75 to .80 a round.
I am on a disability retirement, and only working part time now. I just could not afford to shoot the .300. I sold off the 300 and went back to 5.56. I have my Retro 20" SP1/602 clone and will build "one piece at a time" a super light weight KISS carbine with early CAR15 fiberlite stock, 16" pencil barrel and slick side SP1/604 upper. Hopefully I'll find a 1/7" twist pencil barrel I can afford so I can shoot MK262 Mod 1, occasionally.