ryanryan03 said:
I guess it depends on your purpose. Fun range blaster? Get the 7.5". Lots of people seem to like that barrel length for the fun factor, though it's not really my thing. Though keep in mind if you shoot with other people nearby the noise could make them rather angry at you; 10.5" will be loud as heck also, but not quite as loud.
However, in applications such as hunting and home-defense, the 5.56 gets a lot of its effectiveness from fragmentation when using SPs or JHPs. But often those bullets won't properly fragment out of a 7.5" barrel. I have an acquaintance who shot a few turkeys with a 7.5" .223 using JHPs, and the bullets zipped right through causing minimal damage. The turkeys eventually died, but not immediately.
Many people consider a 10.5" 5.56 barrel to be the minimum length if you want to have enough velocity for reliable fragmentation and/or tumbling. Sharkbite has lots of experience using 10.5" ARs, so I definitely would take his advice on that.
Also, keep in mind that most 5.56 silencers aren't rated for 7.5" barrels. And even if you have one that's rated for it, I wouldn't shoot a silencer too much on a barrel that short; too much unburned powder builds up and you get a huge fireball every several shots. Even if that doesn't destroy the inside of your can, it's going to wear it out a lot faster.
ryanryan03 said:
Also do you prefer the 7.62[x39mm] cartridge vs the 223?
The 7.62x39mm cartridge has trouble being reliable in an AR platform. I'm with Sharkbite: if you want a 30 cal bullet in an AR, use 300 Blackout. Sure, ammo is expensive if you don't reload, but that's why lots of people do most of their cheap plinking with 5.56 and then switch uppers to 300 Blackout when they need a 30 cal bullet or they want to be super-quiet with a silencer and subsonic ammo.
If you want to shoot cheaply with 7.62x39mm, I would recommend a different platform than an AR.
