terminal performance sub sonic isn't better than super sonic in most cases you have to hit some extremes
of course 308 Win that reaches the target with hundreds of fps and fpe is also better than 300 black out
we shoot 300 black-out because it fills some niche purpose not because it is a wonderful hunting round
we are looking for
fits in an AR mag
low recoil
works form a 8-10 inch barrel
sub sonic
something like that
I got into 300blk because we hunt a shotgun and pistol only township. now you can have a 30-06 pistol in WI
there is also no law saying you can't have a 16 inch barrel pistol
so we built pistols with 16 inch barrels that shoot 300blackout because the parts were available and at a decent price at the time.
so our braced pistols fit into the legal pistols to hunt deer with in WI
my dad is also very recoil sensitive with neck, back , and shoulder surgeries over the last 3 decades so I built it to explore proof of concept and then he loved it.
he shot more deer in 3 years with his 300blk than he had in 15 years with his 870 12ga.
he walks himself down to the swamp sits , shoots a deer then walks down to it and calls me or my brother or my son and we come gut and drag it out for him.
honestly I think a well constructed 223 bullet like a triple shock or even 64gr power points would do anything a 110gr 30blk
you only have so much case capacity in 7.62x35 aka 300blk so a good bullet in 5.56x45 leaves you with more case capacity.
if your not wanting to fill the sub sonic niche or a short barrel 6.5 Grendel might be the way to go you get more case capacity but stay in lighter recoiling and fits in an AR , Scuba1 has played with the Grendel and can probably comment more Grendel is a 7.62x39 case necked down to 6.5mm/0.264" this was a round developed by blackwater the private military to make a long range cartridge fit in an Stanag mag and AR platform it requires a barrel , bolt , and mag follower change from a standard AR
300hammer would also be a better option it is Wilson combat's answer to the most punch they could pack in a 30cal super sonic that uses a standard AR bolt face for a 5.56 case head and fits in a stanag mag
https://en.wikipedia.org/wiki/STANAG_magazinethe issue is it didn't take off like 300 black out did mostly because of cost and in-availability.
350 legend lets you push a heavier bullet and more ammo intended for deer is available this was developed by Winchester to fill the niche of a strait wall cartridge state that fits an AR mag
300blk was really developed as a way to put a sub sonic round in an AR platform it's near twin 300wishiper was the wild cat and 300blk is the name sent to SAAMI and in supers it found a following for better terminal performance than 5.56 with a short barrel at close ranges.
before 300blk most agencies were running suppressed MP5 with suppressors and 147gr 9mm
the 300blk shines in a suppressed role from a short barrel because it is a gas gun direct impingement and not a blow back or like the MP5 a roller delay blow back. it also runs the same mags and controls and all but the barrel and gas tube as the AR-15 so parts were very interchangeable which made cost less.
so what niche are you trying to fill , if you can shoot a rifle in your area and want to make deer meat 308win all day long I like it with 180gr bullets