mostly range toy they could be useful for HD less so for hunting
they have an interesting recoil pulse because they are primarily direct blow back there are not direct blow back but mine is direct blow back
they are crazy fun and surely a 10.5 inch barrel would give you about all the velocity your going to get out of a 9mm
so from the ability to put 9mm rounds on target stupid fast like 2x the speed of a pistol yes
from the point of view that a gas operated rifle like an AR in 5.56 or 300blackout would be a little more dependable combat arm
pros
less cost per round
you can train in close on steel safely >25 feet where you can not with 5.56
feeding the same ammo as your handgun
in my case sharing mags with my handgun
less blast than the 10.5 5.56 or the 16 inch 5.56
can be shot on the indoor range
con
it is a pistol round it just doesn't have the energy of a rifle round
direct below back
no last round hold open
so if you put it against a rifle it just doesn't do rifle things as well
but if you put it up against the pistol other than conceal ability it does pistol stuff great
Brigade braced AR9 pistol with a 4inch barrel and an osprey dot sight, runs like a dream and can make accurate hits at an easy 100 yards
While I prefer running standard capacity mags in it I have many of the 33 round ones and a few of the drum mags and so far all have run flawlessly through it, I originally bought it back during the peaceful protest so I could carry it loaded in the vehicle just in case, it has proven to be not only a reliable but also a fun gun to shoot
I also have a kel tech sub 2000 which also takes glock mags, and while it’s a decent gun I also found it kicks a lot more then one would expect from a 9mm firearm, or at least it felt that way to me and I’m not one to really be recoil sensitive but I also wouldn’t sell or trade it because It’s a perfect camp gun for summer camping trips where it spends more time folded up in my pack then anything else
Wolfdog I’d your feeling the itch go ahead and scratch it, i don’t think you will be disappointed, while many of the commercial ones are a bit pricey in my preferred AR style there not that hard to build from off the shelf parts using a standard AR lower and a mag insert, in made one last year as a gift for my brother as a 10 inch barrel pistol for his bday and he loves it, perhaps his most shot firearm