Barrel length effectiveness

Crossbones

Crossbones

Regular
EE Expired
Rating - 100%
1   0   0
Location
Witness Protection Program
I've decided to take my first foray into the AR-15 platform and chose a Spike's Tactical Complete Magpul Edition as a lower receiver. I want to build a shorty and have been eyeballing the PWS DC-10 and the DC-7 as my upper receiver. My question is how much of a difference in range and accuracy is there in three inches of barrel? If there has been a prior discussion on this please direct me to the relevant thread as my search for my topic has not turned up any results. Thanks in advance :)
 
Crossbones said:
I've decided to take my first foray into the AR-15 platform and chose a Spike's Tactical Complete Magpul Edition as a lower receiver. I want to build a shorty and have been eyeballing the PWS DC-10 and the DC-7 as my upper receiver. My question is how much of a difference in range and accuracy is there in three inches of barrel? If there has been a prior discussion on this please direct me to the relevant thread as my search for my topic has not turned up any results. Thanks in advance :)
Click to expand...

Just like your highschool girlfriend I'm sure you'll appreciate every inch. I've heard you can lose up to 100 ft/s per inch or more of barrel lost. 11-12 inches is a good practical shorty without losing too much velocity but the longer the better. Below about 11.5" there isn't sufficient powder burn and then its just for fun. Sure makes a flash hider functionally useless when you burn half your charge out of the barrel on a 7 incher... but it looks pretty at night.
 
Last edited:
Below about 11.5" there isn't sufficient powder burn and then its just for fun.
Click to expand...

And when in Canada is an AR rifle not for fun.

The entire, short barrels reduce ballistic performance is a HUGE moot point in this country cause the chances of any of us actually having to use a personal AR rifle in a deadly force encounter is statistically ZERO.

So get whatever barrel length you want. Whatever rifle configuration you think is fun is as relevant as any other because paper does not care about bullet velocity.
 
Suputin said:
And when in Canada is an AR rifle not for fun.

The entire, short barrels reduce ballistic performance is a HUGE moot point in this country cause the chances of any of us actually having to use a personal AR rifle in a deadly force encounter is statistically ZERO.

So get whatever barrel length you want. Whatever rifle configuration you think is fun is as relevant as any other because paper does not care about bullet velocity.
Click to expand...

Very true !

But if you want long range accuracy a longer barrel is better - the higher velocity round is more stable and bucks the wind better .

Having said that my 10 " AR has never been blown off the gong at 200 yds -

It has shot 1/2 " at 200 yds. with absolutely no wind , and up to 6 inch groups in strong gusty wind.
swingerlh.gif
 
Suputin said:
And when in Canada is an AR rifle not for fun.

The entire, short barrels reduce ballistic performance is a HUGE moot point in this country cause the chances of any of us actually having to use a personal AR rifle in a deadly force encounter is statistically ZERO.

So get whatever barrel length you want. Whatever rifle configuration you think is fun is as relevant as any other because paper does not care about bullet velocity.
Click to expand...

So true, but we have to always be on guard for those pesky zombies :D
Thanks for the advice guys!
 
chopper 1 said:
Very true !

But if you want long range accuracy a longer barrel is better - the higher velocity round is more stable and bucks the wind better .

Having said that my 10 " AR has never been blown off the gong at 200 yds -

It has shot 1/2 " at 200 yds. with absolutely no wind , and up to 6 inch groups in strong gusty wind.
swingerlh.gif
Click to expand...

Wrong firearm for the job. The AR platform is a service rifle, not a precision rifle. If you want long range accuracy/consistency get a bolt gun. However, as you mentioned, short barreled AR's are more than capable of decent accuracy at extended ranges.

TDC
 
TDC +1

A short barrel AR's real forte is not terminal velocity or outright accuracy, it is all about getting on target quickly.

If you fantasize about being a sniper there are much better choices than an AR or short barrel AR. (there a great excuse to buy another gun right?)

I get decent enough groups out of my 7.5" .223 AR at 100 yards that I am not complaining. Up close an personal (<50 yards) it's a hoot to shoot, especially when you have multiple targets.
 
RedDuc said:
TDC +1

A short barrel AR's real forte is not terminal velocity or outright accuracy, it is all about getting on target quickly.

If you fantasize about being a sniper there are much better choices than an AR or short barrel AR. (there a great excuse to buy another gun right?)

I get decent enough groups out of my 7.5" .223 AR at 100 yards that I am not complaining. Up close an personal (<50 yards) it's a hoot to shoot, especially when you have multiple targets.
Click to expand...

Works even better with PWS brake (no muzzle jump)a red dot and a legal 40 rnd mag (4 10 rdrs wedged and bridged)

VERY FAST double taps - Go through a lot of money in ammo tho ::(

(
 
TDC said:
Wrong firearm for the job. The AR platform is a service rifle, not a precision rifle. If you want long range accuracy/consistency get a bolt gun. However, as you mentioned, short barreled AR's are more than capable of decent accuracy at extended ranges.

TDC
Click to expand...

200m is not an extended range for an AR, unless you saw half the barrel off. :dancingbanana:
 
Some hard data I got somewhere concerning velocity and barrel length for 5.56 rounds. Hope it may help your choice.

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 was looking for something fun to shoot and initially thought of getting a 16" barrel but I saw a couple of pics on the web (RRA machine pistol 10.5" and LWRC PSD) and then the PWS Diablo 7" and was in love with the shorty AR from that point onwards. I asked about the barrel length effectiveness out of curiosity and how much change to expect from a typical length AR.
And thanks for the data sofduc :)
 
to answer your original question barrel length has no affect on accuracy (within reason 1" barrel is not going to be accurate) 18 inches seems to be about the right lenth where the highest pressures exist and will give you the best range, at times shorter barrels are more accurate as the harmonics have less affect. Buy the rifle you want to use it for want you want to use it for and have fun. Understanding the science behind it all will take you years.
 
Ive got a PWS DC-10 upper with the CQB comp and its a flawless performer, stays very clean and will get 1.5 to 3 inch 10rd rapid fire groups at 100 yards depending on me :) with a TRG-24 .

The PWS CQB comp makes the DC-10 very quiet(not bad really) and fast on target for follow ups.


IMG_0636.jpg




And just to follow up, I really wish more dealers would carry PWS. Top quality gear! Check out all the goodness you get in a 10.5 long stroke piston carbine for $1549us .
http://primaryweapons.com/store/pc/viewPrd.asp?idproduct=174&idcategory=15
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom