Amount you can carry
Fighting between the big-round and small-round groups reached a peak in the early 1960s, when test after test showed the .223 Remington (M193 5.56×45mm) cartridge fired from the AR-15 allowed an eight-soldier unit to outgun an 11-soldier unit armed with M14s at ranges closer than 300 meters. U.S. troops were able to carry more than twice as much 5.56×45mm ammunition as 7.62×51mm NATO for the same weight, which allowed them an advantage against a typical NVA unit armed with Type 56-1s.
https://en.wikipedia.org/wiki/7.62%C3%9751mm_NATO#Adoption_in_battle_rifles
Interesting chart there too about how much ammo you can carry in a 10kg load of magazines.
260 rounds of 762 NATO
620 rounds of 556
360 rounds of 762 Soviet.
Long Range Effective Accuracy
On the other hand, once you get out to like 300 yards/meters, lighter rounds will get tossed around by the wind, but personally I was having success with very heavy 85gr Open-Tip Match 5.56. But that's premium stuff, and standard 55gr and 62gr projectiles were very hit or miss shooting prone at a 8-inch target.
Recoil and Quickness of Follow-up Shots
.308 out of an AR-10 feels like twice the recoil of 5.56 out of an AR-15. It's not fun. The gun weight too feels like twice as much. If I'm lugging something around I know which I'd prefer.
What are your thoughts? Also, is the new larger US military rifle/caliber contract won by SIG Sauer dead in the water? I think it is, except maybe for specialized roles like DMRs.
This was helpful, I have been thinking about getting a smaller caliber rifle. Only really shot .338 and .50 before.
I don't know anybody with a 5.56 AK to compare against AR-15 though
I haven't shot a 5.56 or 5.54 AK but I did recently get to shoot a 7.62x39 AKM clone. It was very cool, but I'd stick with an AR-15 style platform. AR-15 is far more modular, customizable, and ubiquitous. Also, ergonomics and heat. Hanguard got really hot from the piston system after one mag. Can't do a C-clamp grip with AK iron sights.
I shoot my buddies 101 every other week. It's extremely loud. Like, when we start shooting everyone else at the range snaps their necks over to see what the hell is going on. Zero perceptible recoil tho, it literally feels like shooting a .22. I bet they are amazing in full auto.
However, if you take the muzzle brake off, fixing the noise issue, the recoil becomes a problem. It's still mild, but it feels like it's almost entirely turned into muzzle flip. Making the gun hard to control.
Also, accessories are very expensive. Even basic stuff like, an mlok handguard is a good chunk of $100. The guns don't function properly unless you get the expensive $35-40 mags either. And you have to buy expensive extras to get basic functionality like an optics rail. Plus the guns are really expensive for some reason. Double the cost of an AR of similar quality.
The ergos are also terrible. Like, you can't chamber a round with the safety on, you have to shift your grip to manipulate the fire selector, if you fumble the mag insertion you can cause the gun to jam, you have to reach around the gun to reload, you have to use a riser on your optic or else you have to hold the gun weird to not be blocking the sights with your hand, etc.
They look cool tho.
There are an enormous number of small machine shops in the US that make AR parts as contractors for various arms companies, who in turn have contracts with the military or other buyers. With so many shops turning out parts supply is rarely an issue, shortages are rare, and you can slap together parts from different shops to make a functioning rifles.
On the other hand there are far fewer shops building AKs.
Just basic supply and demand - Everyone makes AR parts and everyone knows how to make AR parts so prices stay low and availability stays high. AKs are a niche luxury product.
If you're in the US get an AR-15. Parts and magazine inter-compatibility is far more important than anything else no matter what nerds with 6k rifles say. If you're not in the US get whatever the most common pattern of local rifle is.
You can have the most comfortable rifle in the world that fits your hands perfectly and it won't matter at all if you can't find ammo, magazines, and parts for it if things go to shit. People also don't consider that you really, really want to be able to share mags with your comrades when shit goes south.