It's not a matter of distance, it's energy on target at any distance. 

Ammo weight is a concern, but... Do push-ups. 🤷‍♂️ 

 And the gun is heavier and longer. 

 Heavier, yes, but it's the same length as my AR15. 

So... No.  

 I will never carry a gun longer than my dick, so I have an AR pistol 10 inch 

 Cool. I don't have that issue, so... 🤷‍♂️ 

 Same
https://i.nostr.build/h7ywfz0Xii2XI1Kc.jpg 

 My friend actually has the north American arms 22 it's very cool and he actually fended off a car jacker with it 

 The only real difference is the ammo. It was Eugene Stoner's original design, but governmemts wanted cheaper ammo, so he modified it to make the AR-15. 

 On paper. 
Building and running them are far different experiences. 

 Possibly, but, not really ask that much for any decently strong enough dude to tote and shoot well, with more energy on target than any 22 caliber bullet can ever hope to achieve. 

Sure, there's a big difference in 308 ammo. That's why you stick with one type and leave it alone once you figure out what the rifle prefers. Tuning one to run on military ball is probably your best bet.  

 I'm not saying it a failure to build and own. Or that or can't be done

Example-
Getting a 6.5 creed chambered ar10 to cycle right makes for an amazing range toy.
(There's a reason i keep several adjustable bleed-off gas blocks on hand)

I'm addressing the claim of "ultimate". 

They are almost always much more finicky and issue prone and it wouldn't be my first choice in a complex situation.

 

 That makes sense. I've yet to finish my 16" 308 build. Maybe I'll find the issues you are talking about. 😅  

 Or maybe you'll be one of the lucky ones that gets it set up right the first time.
Let me know if you do run into issues. I may be able to help.
 

 I *think* I have most things figured out. The one thing I don't know is if the gas port on the upper is sized correctly. It seems some of them aren't from Aero... So, I may end up having to pull the upper apart if it is undergassed.

I've got a solid plan for the buffer system:
A5 length buffer tube 
Tubbs rifle length spring 
Odinworks heavy adjustable carbine length buffer 

I am going to spend the money on a set of go and no go headspace gages. I'm not playing around with 308 being out of spec. That gets into big oof territory if that is wonky.