If you want to claim the 7.62x39 does everything the .300BO does
I don't really need to make such claims. It just does more. Well-proven and widely used as a subsonic round - hey, even my early 90's service rifle, Sako RK95/M92S has a suppressor - it exceeds the legal minimum of 1700J/1254ft-lbs at 100m/110yd with a 123gr or heavier JSP for Finnish class 3 game (whitetail, fallow deer, red deer, sika deer etc.) with factory ammo, surplus ammo is dirt cheap, common and plentiful when you can't be bothered to reload for plinking.
If you really want to select a barrel twist common with the BO off the shelf, any gunsmith can turn one from a blank if need be. I don't really see the point, though. If you want a full power + subsonic combo rifle at ~200gr .30 caliber bullet weight range, regardless of whether you shoot factory ammo or reload, .308Win wipes the floor with either and has done so for decades. My R25 groups 1" at 150m/165yd with Lapua B416 200gr FMJBT subsonics like a clockwork with Jaki Super Classic reflex/telescopic can and reaches out to 400-ish yards at comparable <MOA accuracy with off-the-shelf Hornady 165gr GMX Superformance International. That's pretty much the only suppressed, sub- & supersonic rifle caliber AR I've realized I need, or want for that matter. Its OEM 1:10 twist stabilizes even 220gr reloads nicely, so I wouldn't imagine identical twist on my Mini 30 has any problems doing the same, even though ~180gr are the heaviest bullets I've loaded for it so far.
As far as intermediate rounds and rifle designs other than the AR are concerned, I think I've made my point rather clear by now. I've experimented with the BO myself, and concluded that it doesn't do a thing for me that other rounds wouldn't do better so I gave up on it for a solid reason. And it doesn't even have anywhere near the case capacity for duplicating my favorite, hot, long range 7.62x39 compression loads either.
Like I've said a few times, if you like it and think it fits the bill for whatever you want to use it for, go for it. It has the undeniable advantage of feeding through regular AR mags and magwell if you don't want a dedicated AK mag lower. That's about it.