5.56 vs .223 accuracy - I am thoroughly confused


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.cheese.
June 1, 2008, 02:08 AM
I'm confused on this issue. Here is why.

Here on THR, many many times I have read that in general, .223 is more accurate than 5.56mm even out of a 5.56mm gun.

However, in a recent magazine article, I read just the opposite, that due to the longer lead with 5.56mm, .223 will not properly fill the chamber of a 5.56mm gun, and will reduce accuracy as compared to 5.56mm out of a 5.56mm gun.

So which is it - out of a 5.56mm gun, which would be more accurate - .223 or 5.56mm assuming both are using the same bullet (take Hornady TAP for example where the .223 and the 5.56mm version can use the same bullet). Assume that the distance being shot at is the maximum effective distance .223 allows (just for the sake of maximizing deviation from POA).

I currently have mostly 5.56mm TAP. However, it is even easier to get .223 TAP. Right now I'm just concentrating on accuracy. Not potential for over penetration, not stopping power, not effective range, etc.

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Ridgerunner665
June 1, 2008, 03:09 AM
The closer to the lands (rifling) you get the bullet...the more accurate the round. BUT you can not have it touching the lands...or it may Kaboom!

Now...the OAL of 223 ammo can be slightly longer than 5.56 because of the magazines. Most AR 15 types won't reliably feed anything over 2.26 inches OAL because that is as long as you can fit in the mag...I have 1 mag (out of many) that will feed 2.27...but barely.

I don't know for sure, but I doubt there is any difference in the length of the Hornady rounds you have...5.56 or 223.

But if you want to reload to 2.27 - 2.28 AOL and feed them by hand, one at a time, you can get more accuracy.

The only difference between the Hornady 5.56 and 223 TAP rounds is the powder charge...the 5.56 is a hotter load.

.cheese.
June 3, 2008, 07:14 PM
So was the article wrong then? I think it was in Guns & Ammo, but maybe not.

cpttango30
June 3, 2008, 07:39 PM
BUT you can not have it touching the lands...or it may Kaboom!

NOT true. I know quite a few varmint hunters and benchrest guys that run the bullet into the rifling with no problems. Now for the layman reloader like 99% of us on here I am sure you would get plenty of KABOOMS. But, it can and is done.

csmkersh
June 3, 2008, 07:43 PM
Handloaders often start with the bullet touching the lands and slowly back way with each load until the find the optimum distance off the lands for that particular rifle. That's where micrometer seating dies pay for themselves.

longdayjake
June 3, 2008, 08:26 PM
I think you are having a little bit of confusion. When people say that .223 is more accurate they are probably referring to the chamber. Ar-15 style rifles can be chambered for .223 or 5.56. The chambers for a .223 are tighter to fit the .223 well, whereas the chamber for a 5.56 is built looser so that it can reliably feed for military purposes. Usually when the casing fits tighter in the chamber it is more consistent from shot to shot. So, technically the .223 has better potential for accuracy. I have heard that shooting 5.56 out of a 223 chamber is unsafe so if you go with a .223 chamber you are limited to shooting just the .223. 5.56 chambers will safely shoot both rounds. I have a rock river arms wylde chamber which is somewhere in between the .223 and the 5.56. You can shoot both types out of it and get consistancy with both. I don't know if this helps but there you go.

cracked butt
June 3, 2008, 08:36 PM
The quality of the components are much more important than the .223 or 556 designation. Externally, both cartridges are identical. The 556 cartridges are usually going to have milspec primers/powder/brass/bullets which aren't the best and aren't the worst, commercial .223 is going to be all over the map in terms of quality ( I actually tried a certain brand of ammo this weekend that has a name that starts with 'ultra' and ends in 'max' where I had 3 rounds out of 2 boxes that wouldn't even chamber). With handloading, its very easy to beat the accuracy of 556 ammo- my only experience with 556 is is a few hundred rounds of XM-193 that I've shot which never did better than 2MOA out of my rifle- not bad at all, but Black Hills 52gr match shoots consistantly much better out of my rifle.

As someone mentioned, the AR mags will only take cartridges that are 2.260" or less, so the length of the leade is not really important unless you are shooting a .223 chambered match grade rifle. The longer leade can be overcome by single loading handloads with the bullets seated longer than 2.260".

Swampy
June 4, 2008, 09:19 AM
Originally Posted by Ridgerunner665
BUT you can not have it touching the lands...or it may Kaboom!
NOT true. I know quite a few varmint hunters and benchrest guys that run the bullet into the rifling with no problems. Now for the layman reloader like 99% of us on here I am sure you would get plenty of KABOOMS. But, it can and is done.

Ditto....

It is not just common practice... it is STANDARD practice for most BR, Palma, LR Highpower, varmint, etc... shooters to seat bullets long so that they will either be touching or even jammed into the lands for solid contact. This is how ultimate accuracy is best acheived in the vast majority of rifle/bullet combinations.

Powder charges must be compensated for the possible higher pressures, but to say that it is not or cannot be safely done is pure-D hogwash.

Best to all,
Swampy

Garands forever
2007 NRA Missouri State 600 yard Service Rifle Champion.... with an M1

Onmilo
June 4, 2008, 09:43 AM
My favorite gun magazine "Gun Tests" :D, wrote an article about several top notch varmint specific hunting AR15 rifles.
They came to the conclusion that the Fulton Armory offering was the most accurate and the Bushmaster Varminteer rifle was the least accurate but all the loads tested were caliber .223 Remington and none were in 5.56 Nato caliber.

I have a rifle I built using a 24" Bushmaster stainless steel varminteer/match barrel that will outgroup all the rifles that Gun Tests checked out at 100 meters but only if I use cartridges that are dimensioned to 5.56 Nato specifications.
As a matter of fact the very best groups obtained with this rifle are shot with South African M193 specification full metal jacket ammunition and are consistently sub minute of angle.

Is it the ammunition or the chambering of the barrel or a combination of both?

It is always smart to test fire a number of factory loads in your rifle to determine what will produce the best accuracy.

sadlsor
June 4, 2008, 11:30 AM
I'm often amused by the degrees of emotion surrounding battle rifles and accuracy, in general. Given *most* ARs are perfectly acceptable for *most* hobby-type and general-purpose shooting, the give-or-take an inch here, or two inches there, at the short-to-midrange distances is completely over the top. Unless you simply want bragging rights.

Perhaps I should state that I bought my Bushmaster from CMP, strictly for NRA hi-power matches, so that's my basis. I also roll my own ammo for this purpose, and only use moly bullets. A half-inch, give or take, DOES make a difference in my scores. But I very rarely see hi-power shooting mentioned in any of this type of thread. Besides that, and here's the rub - I can't consistently shoot that well. The gun certainly can, but not me. I'm not a machine and I wasn't put together in a factory.

The one or two inches difference in accuracy doesn't come into play nearly as much, if you're shooting 3-gun or action or tactical rifle matches. Shoot 'n move, or run 'n gunnin' in these scenarios nullifies the perceived accuracy of one gun over another.

That's my opinion, and it should be yours. :)

cracked butt
June 4, 2008, 11:56 AM
I'm often amused by the degrees of emotion surrounding battle rifles and accuracy, in general. Given *most* ARs are perfectly acceptable for *most* hobby-type and general-purpose shooting, the give-or-take an inch here, or two inches there, at the short-to-midrange distances is completely over the top. Unless you simply want bragging rights.

Perhaps I should state that I bought my Bushmaster from CMP, strictly for NRA hi-power matches, so that's my basis. I also roll my own ammo for this purpose, and only use moly bullets. A half-inch, give or take, DOES make a difference in my scores. But I very rarely see hi-power shooting mentioned in any of this type of thread. Besides that, and here's the rub - I can't consistently shoot that well. The gun certainly can, but not me. I'm not a machine and I wasn't put together in a factory.


I pretty much agree.
Mine's a Bushy 20" HBAR. I use it mainly for NRA Highpower, and for practice. If I can shot 10 shots into 2" at 100 yards from a bench with a scope mounted, the ammo and gun are shooting at least twice as good as I can hold at the present time with iron sights. (yeah, it doesn't sound as impressive as people who shoot 2" groups with iron sights using nothing but folded up sweatshirt on the tailgate of their truck as a rest, but amazingly enough those people don't show up to high power rifle shoots) I do handload, mainly to save money at this point, the extra accuracy gained from my reloads probably helps me a lot more psychologically than anything else.

GarandOwner
June 4, 2008, 12:30 PM
I currently have mostly 5.56mm TAP. However, it is even easier to get .223 TAP. Right now I'm just concentrating on accuracy. Not potential for over penetration, not stopping power, not effective range, etc.

Who cares what it does out of other's guns, shoot each out of yours, see which shoots better and then you will have your answer. What works for one gun may not be true for another.

That said, in my opinion, when I reload, I like to have a bullet that is seated as close to the rifling as possible, I find that this makes it more accurate, but thats just me, others might be different.

sqlbullet
June 4, 2008, 12:40 PM
It was Guns and Ammo. The article went on to state that the drawbacks to the longer lead were compensated for by the lower pressure of the 223 loads, and the longer lead and fast twist of the gun in question, a Stag Arms varmint gun in an AR platform, were really helpful to heavier bullets with a longer COL as are used by varmint hunters. Here is a link (http://www.gunsandammomag.com/long_guns/GA_stagssupertack_200806/index1.html). Refence the section titles 5.56 vs. .223.

If your goal is accuracy without other concerns as you state, test the loads in question and settle on the one that provides the best groups. As is always the case when the best accuracy is desired, the cleanliness of theory is no match for the fun of poking holes in paper (or prairie dogs) in practical testing.

strat81
June 4, 2008, 12:51 PM
A few things... most 5.56 ammo is not match ammo, or even "very good" ammo. Most 5.56 is mil-spec where minute of human is fine. With .223, better bullets are available and it may be made in smaller batches which might lead to better quality control.

Hornady TAP is designed for shooting people, not paper. If you want Hornady match ammo, look at their 75gr BTHP Match stuff. I'd also look at Federal Gold Medal and Black Hills Match. I've never heard of a match shooter using V-Max bullets. I'm not saying it's never happened or that no one does it, but V-Maxes are for varmints.

Of course, if accuracy is your primary concern, you'd be handloading.

That being said, rifles are finicky. What works best in yours may not work best in mine. Some rifles like hot loads and ball powders, others don't. Some prefer heavy bullets, others prefer light bullets. Buy a few boxes of ammo and see what yours likes.

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