.223 vs barrel length

6

62bmw

New member
I was ordering my new AR today and I was going to get a 24 inch barrel . My sheriff buddy and gunsmith(former marine armorer) both told me 24" for what I want to do . The builder that I was ordering from said 24 was a bad idea, 20 is better anything over 22 inches and a .223 starts looseing velocity . Any insite on this . I figure a slow accurate kill is a good one , a fast miss is a ......miss. Thanks Bruce
 
My chronograph says different my 24 inch barrel is about 150fps faster than my 20 inch barrel both are AR's.
 
My reading (not personal research) showed that with many loads the 223 and other fast similar rounds, the max velocity is reached in a 24 - 26" barrel. A shorter barrel will lose about 40 fps per inch. You will not lose and often gain accuracy with a short stiff barrel. I found the long barrel out of balance in an AR compared to a bolt gun and would recommend one of each.

There is much to found on this topic on this site.
 
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....both told me 24" for what I want to do.



Hard to answer your question without knowing "what you want to do". /ubbthreads/images/graemlins/confused1.gif

To start with, unless you're planning on LOOOOOOONG range shooting, you're not going to benefit from the extra 4". Not to mention the added weight of the rifle if you plan to tote it anywhere.

Give us more info about your plans for this rifle. /ubbthreads/images/graemlins/wink.gif
 
I bought the 24 inch RR AR and I loved it for long range due to the weight it kept pretty steady but was a tad cumbersome to tote.I sold the upper here in the classifieds and purchased a RR 18 inch upper which is easier to carry swing and point they both have their unique benefits it just depends on how you plan on using it.
 
I retired from the AF 3 years ago after 24 years and too am an armorer. I am also a Colt armorer and my instructor also feels 24" is a good "Reach out and Touch someone" length. I currently own a upper in 24" from DPMS. It is a super shooter. 24" is about the optimum for .223. The best twist (My opinion) is 1 in 9". This allows the use of both light and heavy bullets up to 69gr. Although the heavy barrel is much heaver than a 20" it's what YOU want or need. Your the one who is carrying it.
 
I have two AR-15 rifles. One is set up for long range varminting with a 24" ER Shaw barrel, the other is your basic 16" flattop that I got for carrying around in my truck and ATV and for coyote hunting. Trust me on this one- that 24" barrel is way more comfortable to shoot. Much less blast, easier hold steady, and it shoots a lot tighter groups as well.

I think that the shorter AR looks more like an AR-15 should look like, but I am after performance, not classic lines.
 
The loss of velocity would depend on the powder used in the round. Ideally you'd want all of the powder to burn right before bullet exits the muzzle. A really fast powder could possibly cause loss of velocity with a longer barrel due to friction but I wouldn't think it likely. Matching ammo to the barrel you get shouldn't be difficult no matter what length you choose.

peace.
unloaded
 
Your GS's advice is wrong. Until the volume of the bore exceeds the volume of the burning gases, your velocity will increase with bore length.

In a "typical" .223 Rem loading, approximately 50% of your velocity is attained within the first 6" of barrel length, 75% by 10", and the remainder is graphed as a gentle upward slope for the remainder of your barrel length. Within reason, the velocity increases ~30-50 fps per extra inch of barrel beyond 20" of barrel length.

Theoretically, you could have a barrel too long for your chambering/load, but chances of such a long barrel being available, even a custom one, is pretty remote.

At the practical level, you've pretty much wrung out all you're going to get from a .223 Rem with a 26" barrel. The velocity gains with a barrel longer than that are pretty insignificant with this chambering. Powder choices will of course make a difference, but not enough that your gunsmith's advice could be considered correct when using powders suitable for the .223 Rem.

If I were considering long range shooting with the .223 Rem, I'd certainly opt for the 24" (or 26") tube over the 20".

Mike
 
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My chronograph says different my 24 inch barrel is about 150fps faster than my 20 inch barrel both are AR's.



This is as far as I read. Thanks
 
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Many tests have been performed and state that 24" is the point of diminishing returns on a .223. My 26" is about 10fps (on average) faster than my 24" or 25" barrels (which average out about equal.
 
This rifle has a 21" barrel and a mid length handguard on it. It's 30 fps slower than my 22" rifle but a little better handling.

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Your gunsmith gave you some very WRONG advise in saying that the velocity started slowing down after 20". That statement is right up there with the American Govm't introduced aids to rid the Earth of Black people. Are you sure you understood him properly?

AR's with a 24" barrel can be very unwieldy in handling which is probably what prompted him to say such an outlandish thing.
 
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the longer the berrel the mor time the gases push the bullet withch = faster speeds


Only if you are using a slow burning powder. With a fast burning powder the powder will be burnt before it reaches the end of the barrel and the extra barrel length will slow the bullet down.
 
Figure about +30-35 fps for every inch of barrel between 20"-26".

3550-3600 fps with 50g Bullets is ho hum for a 26" barrel, try that from a 20" barrel. Having said that, the 55's out of a 26" barrel will get 3450+ depending on the powder used.

If you have some big Max SAAMI spec chamber, you are loosing a lot of gasses blowing by the bullet before the bullet ever obturates in the rifling, thus an additional loss in velocity. Max SAAMI spec chambers do not see the velocity gains in barrel lengths that Minimum SAAMI spec chambers see.
 
I'am useing this gun for coyotes and prarrie dogs . The "semi-custom" builder of the rifle told me not to get the 24" . After talking with the builder and his sales associate several more times I decided to opt out of the deal . He offers 3 different barrell lengths , the one I want he big deals , what a pain it is to get the barrell , I go for the next option a 22 " , he say's that'a a better shooter but he has to find a 24" and cut it down . Then I realise in 2 weeks the price has changed 3 times and gone up 100.00 with no upgrades . Thanks for the education . Bruce
 
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the longer the berrel the mor time the gases push the bullet withch = faster speeds


Only if you are using a slow burning powder. With a fast burning powder the powder will be burnt before it reaches the end of the barrel and the extra barrel length will slow the bullet down.



It doesn't make any difference when the powder is "burned out", as the gas pressure will still push the bullet.

Whether burned out at 12 inches or 15 inches, 26 grains of powder makes ~26 grains of gas, and that gas takes up the same amount of space, no matter what.

The speed of the powder might make small differences in pressure, but not enough to stop the acceleration down the barrel.


.
 


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