Barrels less than 10.5". Let's say 8" or 9". Let's also establish that we're talking about out to 200 meters max. Now a PDW is obviously intended for CQB-type distances but if need be you could reach out and touch someone at intermediate ranges. Not talking a hill-to-hill shootout in Afghanistan but within 200m.
From chrono data I've seen over the years 5.56 NATO (not talking .223) starts to really fall off terminal performance-wise with barrels < 10.5". However, 300BLK is designed for short-azz barrels, namely in the "PDW" envelope I'm referring to.
So the hypothesis I'm putting forward is that in barrels shorter than 10.5" the 300BLK will surpass 5.56 terminal performance out to 200 meters. You go 10.5" or longer and the 5.56 shines (with good ammo of course).
Fire away.
Bookmarks