.223 Rem best barrel length bullet weight combo


September 14, 2010, 05:06 PM
What is the best (ballistically speaking) barrel length to bullet weigt combo in 5.56/.223?
I thought I saw a table somewhere, can' t remember where...

Or, what is the best compromise and what twist rate ?


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September 14, 2010, 05:21 PM
I think this comes down to what your looking to do with the gun. Pretty much a longer barrel will always be better till you reach the point of no useable return (id guess someplace out around 30" or so for a .223, but thats very slightly educated guess). Personally I like 24"s with 1-9" twist, and 55-70grn bullets. But again this is personal prefferance, i dont like short rifle, dont shoot a semi at this time and weight of the gun isnt an issue. I also used my .223 (its changed to a 6x47) for goats and deer not ground hogs or chucks.

If i was building a semi, or a light rifle, id go with a 20-22" barrel. A defensive rifle for indoors shorter still.

September 14, 2010, 05:38 PM
Forgot to mention that it would be a AR-15.

September 14, 2010, 05:42 PM
maybe post your likely uses and im sure there will be a number of very knowledgeable people who can help you out with recomendations and options. Im going to have to bow out of this question for the simple fact ive GASP!!! never used an AR

Jim Watson
September 14, 2010, 05:47 PM
Same question still applies, what is it FOR?

The Army thought 20" was about right for marching and shooting, 14.5" for getting in and out of vehicles.

I have a 28" that is a good shooter but not much fun to carry farther than from the car to the firing line.

A 14" twist was always good for target and varmint bullets up to 55 grains, 12" for 55 gr FMJ boattails, 9" for 68 gr match, 7.5-8" for 75-80 gr match, 7" for M855 ball and M856 tracer, 6.5" for 90 gr match.

Bear in mind that most heavy bullet target loads are too long for the magazine and are used single shot slowfire. The military ammo and 77 gr target loads are magazine length.

September 14, 2010, 06:49 PM
It would be used for long range 'self defense'.

Like to get the most performance out of a AR-15 type barrel - which should also be quite useful at close range, right?

Want to avoid getting to short a barrel which defeats the original concept.

OAL of the cartridge needs to be short enough to fit in a magazine.

Thanks to all for answering.

September 15, 2010, 12:11 AM
....er could you define "long range self defense". I Dont think ive heard of anyone getting robbed by a crook with a DMR from 300yds...(just trying to be funny, tho i would like a bit more of an explanation)

September 15, 2010, 12:17 AM
It would be used for long range 'self defense'.

I suppose some jurors in Texas or Montana might not laugh at that concept... sure wouldn't try it around here.

20" is a nice compromise, and 1:8 twist lets you shoot any bullet that will fit into a standard magazine. 1:7 lets you shoot the same bullets at -50 F. if that's important to you. (An AR will likely be a single shot bolt action, at best, at that temperature...) 1:9 lets you shoot most common bullets up to 69gr match and 62gr SS109 (used in M855 ammo) and also won't make 45-50gr varmint bullets blow up 10 feet out of the muzzle from excessive spin.

Personally, if I needed "long range 'self defense'" I would grabbing a .308 with an 18" barrel, but that's just me.

Jim Watson
September 15, 2010, 01:44 AM
I'd get the 8 twist if the rifle I otherwise liked was made with it, otherwise USGI 7 twist. I would load up on M855/SS109/"green tip" hardball and try to buy, scrounge, or handload some Mk 262 with 77 gr SMK.

September 15, 2010, 12:04 PM
I get great results from a 20" Bull barrel 1:9 twist using 69gr bullets. Plenty accurate @ 300 yards.

September 15, 2010, 12:27 PM
1:9 from 16-20" seems to be the most common combination as you can shoot the widest variety of bullet weights while keeping velocity. Its also the combo most frequently offered by AR manufacturers, there is a reason for that.

A more important consideration is to make sure you match up the proper gas system and buffer to your barrel length.

September 16, 2010, 07:40 AM
Thanks to all - that answers my question.

Double Naught Spy
September 16, 2010, 08:04 AM
Long range self defense and located in the desert SW? Hmm. I think I would want something bigger than .223.

While the 1:9 will give you the best range of cartridge options, you might want to consider 1:7 and using heavier bullets, such as 75 gr instead of the old standard 55 gr. or current military standard 62.

Art Eatman
September 16, 2010, 09:04 AM
Since the OP says he's happy...

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