Someone give me the quick low down on barrel lengths.. i'm sure the answer will be "it depends". I know of course it depends on what the purpose is.. but "generally" what are the popular lengths? Are the pros/cons just the usual stuff that would apply to any weapon (accuracy) ?

 

I won't even ask about twist rates here.

 

i dunno.. in some pics it looks like barrels are sticking out 8 inches past the gas block.. and in others it looks like 3 inches. Could this be because gas blocks are at different lenghts too?

 

like for example.. these both say 16" but one barrel looks way bigger than other.. just an illusion?

 

http://www.budsgunshop.com/catalog/product_info.php/cPath/977/products_id/71971/Rifles/Smith+%26+Wesson+Rifles/M%26P+15+Rifles/S/W%20M/P-15%20SPORT%205.56%2016/quot;%2010+1%20CA%20Compliant/

 

http://www.budsgunshop.com/catalog/product_info.php/cPath/977/products_id/53497/Rifles/Smith+%26+Wesson+Rifles/M%26P+15+Rifles/Smith%20/%20Wesson%2010%20+%201%20223%20Remington%20Carbine%20w/16/quot;%20Barrel/

 

Or is it something else this AR newbie isnt catching.

You might be deceived by the length of the handguard/rail systems. The first one has a carbine handguard and the second has a mid length quad rail. The first has a fixed front sight post whereas the second has a back up iron sight mounted on the rail. Welcome to the world of the AR where combinations are near endless.

 

 

 

 

 

 

What are you looking to do? Range/plinking? Run & Gun competition?

Anybody have a 24" barrel? I've seen them for sale but never saw one assembled.

The barrel lengths often correspond to the gas system. The original AR configuration was a rifle length gas system and a 20 inch barrel to maximize velocity. Any barrel longer than 20" uses a rifle gas system. The carbine length gas system was invented to allow for a shorter rifle with a 14.5" barrel. The gas block is closer to the receiver. The recoil impulse is a little more sharp. It is on the majority of non-precision ARs you see. The midlength gas system is a recent invention. It is just what you think, midway between rifle and carbine gas system. It is optimized for 16" barrels. Of course there are exceptions to these.

Rubber: that animation is AWESOME.. i will watch it for hours... is the short barrel 14 inch? then 16? then 18?

 

KRD: still in infancy stage here.. i doubt i will be running with it though.. i'm not that extreme.... YET!

 

Lunker: i'm not looking to shoot 200+ yards so i think 16 is just fine for a suburb guy like me.. ?

 

is the difference between 14.5 and 16" anything significant? would people that pick 14.5 be guys that are thinking CLOSE QUARTERS, like a guy who picks an 18" shotgun?

 

Oh, and in that animation was the gas block/capture spot ont the barrel the same for all those lenghts? or did it get farther out as the barrel got longer? yeah what i think threw me was the extension of the rails past the block.

Your best bet would probably be a 16" Carbine or Midlength. My first AR was a 16" Carbine. It's a pretty decent AR and I built it for a relatively cheap price. I just assembled a 14.5" Midlength and it's a nice shooter too.

Remember that all these barrel lengths do not include a muzzle device. 16" is the Federal minimim lngth, which can include a permanently attached muzzle brake. You have to decide whether you want to put three shots into a dime sized grouping (heavy rifle with 20+" heavy barrel) or a light, fast handling carbine (carbine/mid length gas and 14.5-16" barrel), or something in between. Will you be shooting from a bench, prone, standing, run-and-gun?

Anybody have a 24" barrel? I've seen them for sale but never saw one assembled.

 

24" Is the top.

 

compare the different lengths.

24" Is the top.

 

compare the different lengths.

 

Does the 24" barrel make for much better accuracy over a 20"?

 

 

Also is 24" the longest barrel in production for ARs?

16" is the popular length.

 

Of course it depends. How good is your vision? Do you plan to shoot with irons, red dot or scope? I shoot with a red dot at 100 to 150 yards tops and with my middle aged vision, a 16" gives me all the accuracy I can handle. In other words, going longer than 16" won't help me.

Barrel length has more to do with velocity and range than it does with accuracy. I regularly shoot a 11.5" Colt R0933, and I am just as accurate with that as I am with a 14.5" M4 or my 16" mid length AR, at distances appropriate for the short barrel.

 

The extra barrel length allows the projectile to build more velocity before leaving the muzzle, increasing lethality at greater distances, and giving the projectile longer range.

 

The longer barrel also allows you to have a rifle length gas system, which is arguably more reliable than the carbine length gas system found on most 14.5-16" ARs or the mid-length gas system that is becoming more popular for its subjectively softer recoil.

Barrel length has more to do with velocity and range than it does with accuracy.

 

True but a higher velocity bullet gets to the target faster which means less drop and wind drift. So in a roundabout way you could still say it helps with shot placement

The rifle length also has a longer sight radius and a smaller looking front post if you're using iron sights. The smaller front post should (in theory) translate to a better grouping at distance.

this is my very short summary, of info i have read online when researching. i am by no means an expert. just an accumulation of observations that i have managed to retain. anyone is welcome to correct me if i am misspeaking to anything.

 

16" is minimum by law.

you can do a 14.5" or 14.7" with the NJ required welded compensator or brake to bring to the legal minimum of 16". no flash hiders in NJ.

beyond that, its up to you for use and preference. i chose 16"

 

gas system length - carbine vs midlength vs rifle

carbine is shortest, most felt recoil, most reliable, fastest cyclic rate - mil-spec. midlength is is slightly longer, slightly slower, just as reliable, less felt recoil. rifle length is longest... i chose midlength.

 

twist rate - 1:7 / 1:8 / 1:9... others

1:7 is mil-spec, most accurate for heavier bullets, 64 - 79 grain. will shoot 55 grain xm193 fine, but less accurately. 1:8 covers the spread from 55 grain to 72 grain. most 223 target guns are rifled at 1:7.7 which is mathematically the best. 1:9 is best for lighter weight 55 grain bullets - ideal for a plinking/target gun. i chose 1:8.