>>64123344
>mechanically-illiterate
Literally just google it. Most off the shelf 300blk loadings use bullets with better BCs than the off the shelf 7.62x39 rounds.
>You can use 308 in x39
No one is talking about your autistic hobby of home loading 7.62x39 with a handful of nice high BC .308 bullets.
>Fucking horseshit, x39 has more case capacity, it makes more energy at ALL barrel lengths.
>case capacity
Once again, no one gives a shit about your gay reloading hobby boomer. Factory ammo to factory ammo, for the barrel lengths of interest (7-9"), 300blk has more muzzle energy (supers). And no one gives a shit about 11-16" barrel lengths in a 300blk discussion because said long barrels entirely defeat the purpose of a short subsonic/supersonic capable rifle.
>Factory ammo? So you're cheating the comparison
>Factory = cheating
What the fuck are you going on about? For literally 99% of of shooters factory ammo is all that we care about or consider, and guess what, factory supersonic 300blk beats out factory 7.62x39 in barrels 7-9"
Deal with it.

Also this entire conversation is fucking stupid because 7.62x39 doesn't reliably cycle subsonics in short platforms of any type, 300blk does. The entire point of the cartridge was that you can hot swap subs to supers in a tactical situation.