Just how much is lost going with a 16 in barrel in 223/5.56 instead of a 20 in barrel?


howdy

About 40-60 FPS.

You'll lose not more than around 20fps/in. of barrel lost from a 20" barrel down.

What barrel length would you recomend for a first build?

howdy

I would recommend an 18" or 20" barrel if you are building a target upper. I recently went from a 20" barrel to an 18" barrel as I loose very little in terms of velocity w/ 55gr-62gr bullets and about 50fps w/ the 75gr/77gr bullets. A 16" barrel looses about 150fps from a 20" barrel.

The following is something I ran across on arfcom.

LIMITED DATA, ADMITTEDLY, BUT I THINK IT'S INTERESTING:




MK 262 VELOCITY DATA
__________________________________


7.5" 2053 FPS ... 10.5" 2363 FPS
DIFFERENCE 310 FPS
DIFFERENCE/INCH 103 FPS

10.5" 2363 FPS ... 14.5" 2576 FPS
DIFFERENCE 213 FPS
DIFFERENCE/INCH 53 FPS

14.5" 2576 FPS ... 16" 2669 FPS
DIFFERENCE 93 FPS
DIFFERENCE/INCH 62 FPS

16" 2669 FPS ... 18" 2769 FPS
DIFFERENCE 100 FPS
DIFFERENCE/INCH 50 FPS

18" 2769 FPS ... 20" 2818 FPS
DIFFERENCE 49 FPS
DIFFERENCE/INCH 25 FPS



M855 VELOCITY DATA
__________________________

7.5" 2244 FPS ... 10.5" 2639 FPS
DIFFERENCE 395 FPS
DIFFERENCE/INCH 132 FPS

10.5" 2639 FPS ... 14.5" 2861 FPS
DIFFERENCE 222 FPS
DIFFERENCE/INCH 56 FPS

14.5" 2861 FPS ... 16" 2938 FPS
DIFFERENCE 77 FPS
DIFFERENCE/INCH 51 FPS

16" 2938 FPS ... 18" 3046 FPS
DIFFERENCE 108 FPS
DIFFERENCE/INCH 54 FPS

18" 3046 FPS ... 20" 3061 FPS
DIFFERENCE 15 FPS
DIFFERENCE/INCH 7.5 FPS


XM193 VELOCITY DATA
_________________________________


7.5" 2364 FPS ... 10.5" 2755 FPS
DIFFERENCE 391 FPS
DIFFERENCE/INCH 130 FPS PER INCH

10.5" 2755 FPS ... 14.5" 2984 FPS
DIFFERENCE 229 FPS
DIFFERENCE/INCH 57 FPS PER INCH

14.5" 2984 FPS ... 16" 3075 FPS
DIFFERENCE 91 FPS
DIFFERENCE/INCH 61 FPS

16" 3075 FPS ... 18" 3245 FPS
DIFFERENCE 170 FPS
DIFFERENCE/INCH 85 FPS

18" 3245 ... 20" 3254 FPS
DIFFERENCE 9 FPS
DIFFERENCE/INCH 4.5 FPS

I think of .223 as a carbean round. I don't see the need in a carbean with more than a 18" barrel max with 14.5"-16" being about right.

my $.02,
LM

BTW spelling nazis I know how to spell carbine

18" or 16". I went 16" and love it. 18" with a rifle length gas system is smoother. I was more interested in point ability and length with a can. It makes a diff.

I prefer 20" because it is quieter and uses a rifle length system which is the most reliable and softest. Depends on what you want to use it for, but for hunting and long range shooting, a longer barrel will server you better.

Depends on your intended use. Personally I like shorter Barrels the reasons mentioned. A mid lenght gas system is a good compromise if that's important to you.

yeah it will be a hunting/ skin out rig (if need be). I like the idea of a 16" barrel but I know the capabilites of the 20" with an M-16.

Thanks for all the comments guys
Howdy

I split the difference and used a fluted 19" shilen barrel. Less weight on hunting rig and not as loud as 16" and 18". I don't see how guys carry those .920 24" barrels around all day.

I think of the .223 as a Varmint round, and try to optimize my rifles in that chambering for max velocity/range.

For CQB, a short barrel is better, and I like either the 44MAG or the 20ga.

If I ever need to whack at someone across spitting distances, I'm going to want to whack at them with something that has a bunch more punch than a woodchuck slayer. Personally, I can't handle a lot of 12ga recoil, so I choose something that has shotgun capabilities, with recoil I can take a more repetitions from.

Greg

I'd go the the 16" given your intended use or even a 14.5 with the pinned flash suppressor to avoid the NFA bull. My only other "must haves" would be a chrome lined bore/chamber and a 1:7 twist. Apart from that the world's your oyster.

I would say go with an 18" with rifle length gas system. Good compromise of 16" and 20". But if you plan on getting a 16" at some point.. I'd go with the 20".