Depends on it's needed use . The .30 is light and handy but not accurate past about 200 and is kind of weak . Ars are in 5.56 and 300Blackout ( which can do anything a 30 carbine can do and more ) and my close-in favorite , .458 Socom . It can be in the 45-70 class of whoomph with 10 shots of 300 gr bullets or push a 500 grain slug at close to 1500 ( or 1000-1100 ish suppressed out of a 8 inch barrel ) . Fast twist 10.5 inch barrels are available now and fast twist 8 inchers by early next year ( stabilized for suppressor use ) .
Chris