.223 Rem vs 5.56 x 45 NATO Accuracy

[ZeeOSix]

Originally Posted By: billt460
There isn't enough difference to worry about. I no longer segregate my 5.56 MM and .223 brass because there is no need to. Also, I have never heard of, or seen a .223 rifle damaged from shooting 5.56 MM ammunition in it..... Ever. Not even as much as a damaged extractor.


I thought this was a good article by Cheaper Than Dirt.

http://blog.cheaperthandirt.com/ar-15-223-mil-spec-5-56mm-chambers/

 

[ZeeOSix]

Originally Posted By: hatt
Originally Posted By: Shannow
My CZ527 being made in the same factory as the mil stuff has the NATO chambering...well at least I can seat a 63 gr military projectile completely out of a properly trimmed case and still not touch the rifling (boat-tail is still in, but not gripped).

Can't shoot mil stuff with the 1:12, but it will still do MOA with 60gr VMax punted as fast as I can with AR2206 (close to 3031).
1:12 is perfect for M193.


M193 is 55 grains

From AR15.com:

About Barrel Twist
By Corey Sattler ([email protected])

Here is the info I have collected for .223 twist ratios from various sources (including in-house testing & ammo manf. contacts).

1x7 - technically too tight of a twist for any .224 bullet widely available, including the 80 gr. Manufactured originally to stabilize SS109 and/or tracer ammo, but further military testing has shown other twists to be superior. Some of the very heavy custom stuff (87 gr?) may work well, but why????

1x8 - great twist for 69-80 gr bullets. Sierra once informed me that the perfect twist for their 80gr was 1x8.2xxxxx (blah blah blah big long engineers explanation followed).

1x9 - good all around twist ratio. Best suited for 52-69 gr, but either end of the envelope will be questionable.

1x10 - practically the same as 1x9, but favors the lighter side a little more.

1x12 - great for the 40-52 gr bullets. Most often found on bolt action rifles as their primary use is varminting. All right for the 55 gr, but not the best.

1x14 - if you want to under stabilize the .224 bullet, use this twist. Useless except for tumbling effect it causes upon bullet impact. IMHO, better to shoot straight with a good HP bullet as your chances to hit are better and damage will most likely be greater also.

And also:

Barrel Twist
The barrel’s twist rate refers to the distance a bullet travels in the barrel to complete a full revolution. For instance, a 1/9" twist means that the bullet will make a complete revolution for each 9 inches traveled in the barrel. Heavier bullets require a faster twist rate to stabilize them correctly, but too fast of a twist rate will potentially cause a bullet to spin apart. For this reason it is important to match a barrel to the bullets being fired. In selecting a single twist rate for the survival AR, either a 1/7" or a 1/9" will serve the purpose best. These barrels are designed for bullets from 55 to 62 grains, and these are the weights that will most likely be used in survival. The 1/9 is the better of the two, but the majority of Colts/military barrels are 1/7.

 

[Shannow]

Zee0Six,
the 60gr V-Max's are a flat base rather than a boat-tail, so I can get away with the 1:12 with that...have used them out to 600 yards on targets and still nice neat holes.

Greenhil formula is that T=150/L, where both the twist and Length (of the bullet) are in calibres...so a 1:12" .223dia barrel can stabilise things up to 0.62" long theoretically...I always take it that the poly tip is much less dense than the bullet itself and give it a little more leeway.

The A-Max 52gr has the same BC, and I can drive them faster by far, so if I ever get my reloading thing happening again, that's where I'm headed.

 

[demarpaint]

Originally Posted By: ZeeOSix
Originally Posted By: hatt
Originally Posted By: Shannow
My CZ527 being made in the same factory as the mil stuff has the NATO chambering...well at least I can seat a 63 gr military projectile completely out of a properly trimmed case and still not touch the rifling (boat-tail is still in, but not gripped).

Can't shoot mil stuff with the 1:12, but it will still do MOA with 60gr VMax punted as fast as I can with AR2206 (close to 3031).
1:12 is perfect for M193.


M193 is 55 grains

From AR15.com:

About Barrel Twist
By Corey Sattler ([email protected])

Here is the info I have collected for .223 twist ratios from various sources (including in-house testing & ammo manf. contacts).

1x7 - technically too tight of a twist for any .224 bullet widely available, including the 80 gr. Manufactured originally to stabilize SS109 and/or tracer ammo, but further military testing has shown other twists to be superior. Some of the very heavy custom stuff (87 gr?) may work well, but why????

1x8 - great twist for 69-80 gr bullets. Sierra once informed me that the perfect twist for their 80gr was 1x8.2xxxxx (blah blah blah big long engineers explanation followed).

1x9 - good all around twist ratio. Best suited for 52-69 gr, but either end of the envelope will be questionable.

1x10 - practically the same as 1x9, but favors the lighter side a little more.

1x12 - great for the 40-52 gr bullets. Most often found on bolt action rifles as their primary use is varminting. All right for the 55 gr, but not the best.

1x14 - if you want to under stabilize the .224 bullet, use this twist. Useless except for tumbling effect it causes upon bullet impact. IMHO, better to shoot straight with a good HP bullet as your chances to hit are better and damage will most likely be greater also.

And also:

Barrel Twist
The barrel’s twist rate refers to the distance a bullet travels in the barrel to complete a full revolution. For instance, a 1/9" twist means that the bullet will make a complete revolution for each 9 inches traveled in the barrel. Heavier bullets require a faster twist rate to stabilize them correctly, but too fast of a twist rate will potentially cause a bullet to spin apart. For this reason it is important to match a barrel to the bullets being fired. In selecting a single twist rate for the survival AR, either a 1/7" or a 1/9" will serve the purpose best. These barrels are designed for bullets from 55 to 62 grains, and these are the weights that will most likely be used in survival. The 1/9 is the better of the two, but the majority of Colts/military barrels are 1/7.


The right twist and barrel length is the name of the game. I have a few custom rifles ranging from 6.5x284, up to 30x338 Lapua. I had them built around the bullet I planned on using. There are a lot of people out there getting into reloading, learning about BC, heavier bullets etc. and wondering why bullets key-holing, etc. when they hit.

 

[demarpaint]

Originally Posted By: Shannow
Zee0Six,
the 60gr V-Max's are a flat base rather than a boat-tail, so I can get away with the 1:12 with that...have used them out to 600 yards on targets and still nice neat holes.

Greenhil formula is that T=150/L, where both the twist and Length (of the bullet) are in calibres...so a 1:12" .223dia barrel can stabilise things up to 0.62" long theoretically...I always take it that the poly tip is much less dense than the bullet itself and give it a little more leeway.

The A-Max 52gr has the same BC, and I can drive them faster by far, so if I ever get my reloading thing happening again, that's where I'm headed.


I had good luck with 60 gr. V-Max bullets in my Remington 700 22-250. IIRC it has a 12 twist. They're a nice bullet.

 

[billt460]

Originally Posted By: ZeeOSix
Originally Posted By: billt460
There isn't enough difference to worry about. I no longer segregate my 5.56 MM and .223 brass because there is no need to. Also, I have never heard of, or seen a .223 rifle damaged from shooting 5.56 MM ammunition in it..... Ever. Not even as much as a damaged extractor.


I thought this was a good article by Cheaper Than Dirt.

http://blog.cheaperthandirt.com/ar-15-223-mil-spec-5-56mm-chambers/


"So when you shoot 5.56 in a .223 chamber, the case cannot expand as much as it would in a 5.56 chamber.

Therefore, a couple of things happen with varying frequency. The most common is that you will blow primers; that means you will have the primer blow back into the receiver, which decreases reliability as it rattles around in your receiver or on top of your magazine.

You also will experience an increase in failures to eject the spent cases because the case has expanded so much from the hotter load in the smaller chamber, and you may not get the case out of the chamber without putting a rod down the barrel."

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I hear and read this stuff all the time. However in over 45 years of shooting .223 / 5.56 MM ammunition in a dozen different AR-15 rifles, along with shooting 5.56 MM in 3 Ruger Mini 14's, I have yet to experience either. In fact, all my 3 Ruger Mini 14 rifles have EVER SEEN is 5.56 MM ammunition. 2 of them will not even eject properly with light varmint, factory .223 loads. A lot of this stuff gets regurgitated over and over on the Internet, without using any documented cases as proof. As always, there is a big difference in what CAN happen, in regards to what actually DOES happen. I CAN get killed the next time I get in a car or plane. However, is the risk enough to change how I travel?

Shooting 5.56 MM ammo in a .223 chamber, is no different than shooting Weatherby Magnum ammunition in a non Weatherby rifle that is not free bored. Weatherby Mark V Rifles have always been free bored. It is what allowed Roy Weatherby to achieve higher velocities without creating dangerous pressures. When Remington, along with several other manufacturers, started chambering their bolt action rifles for Weatherby Magnum calibers, most all of these rifles were NOT free bored. It was perfectly safe to shoot Weatherby brand ammunition in them. In fact on many of them, (not Remington), it was so stamped right on the barrel to ONLY shoot Weatherby ammunition in them.

This is no different today when shooting 5.56 MM in a .223 chamber. Yes, through the years most all high performance ammunition has been downloaded, because of the current legal climate we all reside in. But it holds true for .223 / 5.56 MM, as it does for the Weatherby Magnum calibers as well. If you doubt that, simply pick up a loading manual from the early 70's, and compare it to the latest edition of any manual being published today. ALL the maximum loads have been significantly reduced.

If .223 chambered rifles were being blown up, damaged, or jammed up by shooting 5.56 MM ammunition in them, you would be seeing examples of it all over the Internet and You Tube. You don't because it simply isn't happening. Because of that, I no longer even bother to segregate my loads, and or cases. There is simply no reason to. This is yet another in a long list of Internet myths that live on without ANY actual proof backing it up.

 

[hatt]

Originally Posted By: Shannow
Oz use the 62 grain which goes through the target sideways at 300 yards.
You guys can't get the 55 grain M193 ammo? There's really nothing special about M855/SS109 unless you're punching through Russian helmets at 500 meters. M193 actually punches through steel at close range better because of the higher velocity. The Israeli firm IMI makes some nice M193 if it's imported down under.

 

[Huie83]

I shoot both in my cheap PSA PTAC build AR, the barrel is a 1:7 twist, non chrome lined. Out to 200 yards I haven't seen any real difference between .223 and 5.56, shoots pretty much the same. 5.56 seems a tad more snappy if that makes sense. I usually shoot M193 if I can find it, or the Federal .223 AR ammo in the black box.

I've even shot 2-300 rounds of cheap Wolf .223 steel case when just messing around out to 75 yards or so, shoots just fine for me. I wouldn't shoot it all the time but some people freak out about shooting steel case in their AR's.

 

[ironman_gq]

I've shot both from a few different AR's. Inside of 150-200yds using decent quality ammunition you won't see a whole lot of difference in accuracy, not enough to rule out the shooter. Whats more important is the quality of the barrel and the quality of the ammunition unless your shooting out to 4-500yds or farther and using very precise handloads there isn't much difference between chambers.

Basically if your shooting under 300yds and using factory ammunition then there is going to be more variation from the ammunition than from the chamber.

As far as the differences between the two, the case dimensions are the same, loads are to different specs. .223 is built to SAAMI specs and 5.56 is built to NATO specs. Pressure differences aren't really as large as they seem when fired in their respective chambers but NATO and SAAMI. The listed difference has more to do with the method used to measure the case pressure than any actual difference. Pressure signs from firing 5.56 in a .223 chamber come from the shorter throat causing a pressure spike, firing a 5.56 in a NATO chamber produces roughly the same pressure as a .223 fire in a SAAMI chamber.

 

[Ws6]

Originally Posted By: ZeeOSix
From what I've researched, a rifle chambered for 5.56 x 45 NATO can also safely shoot .223 Remington, but the accuracy when shooting .223 Rem may suffer. Has anyone verified this in their own rifle at the range?

Also, they say that if your rifle is chambered for only .223 Rem that using the 5.56 x 45 NATO round can be dangerous. My AR is chambered for the 5.56 x 45 NATO spec, but I'm wondering if accuracy will really be noticeably better using the NATO round vs. the .223 Rem.


The accuracy difference really isn't notable unless you're seriously courting 0.75moa or better.

 

[Ws6]

Originally Posted By: ZeeOSix
Originally Posted By: hatt
Originally Posted By: Shannow
My CZ527 being made in the same factory as the mil stuff has the NATO chambering...well at least I can seat a 63 gr military projectile completely out of a properly trimmed case and still not touch the rifling (boat-tail is still in, but not gripped).

Can't shoot mil stuff with the 1:12, but it will still do MOA with 60gr VMax punted as fast as I can with AR2206 (close to 3031).
1:12 is perfect for M193.


M193 is 55 grains

From AR15.com:

About Barrel Twist
By Corey Sattler ([email protected])

Here is the info I have collected for .223 twist ratios from various sources (including in-house testing & ammo manf. contacts).

1x7 - technically too tight of a twist for any .224 bullet widely available, including the 80 gr. Manufactured originally to stabilize SS109 and/or tracer ammo, but further military testing has shown other twists to be superior. Some of the very heavy custom stuff (87 gr?) may work well, but why????

1x8 - great twist for 69-80 gr bullets. Sierra once informed me that the perfect twist for their 80gr was 1x8.2xxxxx (blah blah blah big long engineers explanation followed).

1x9 - good all around twist ratio. Best suited for 52-69 gr, but either end of the envelope will be questionable.

1x10 - practically the same as 1x9, but favors the lighter side a little more.

1x12 - great for the 40-52 gr bullets. Most often found on bolt action rifles as their primary use is varminting. All right for the 55 gr, but not the best.

1x14 - if you want to under stabilize the .224 bullet, use this twist. Useless except for tumbling effect it causes upon bullet impact. IMHO, better to shoot straight with a good HP bullet as your chances to hit are better and damage will most likely be greater also.

And also:

Barrel Twist
The barrel’s twist rate refers to the distance a bullet travels in the barrel to complete a full revolution. For instance, a 1/9" twist means that the bullet will make a complete revolution for each 9 inches traveled in the barrel. Heavier bullets require a faster twist rate to stabilize them correctly, but too fast of a twist rate will potentially cause a bullet to spin apart. For this reason it is important to match a barrel to the bullets being fired. In selecting a single twist rate for the survival AR, either a 1/7" or a 1/9" will serve the purpose best. These barrels are designed for bullets from 55 to 62 grains, and these are the weights that will most likely be used in survival. The 1/9 is the better of the two, but the majority of Colts/military barrels are 1/7.


All my rifles are 1/7. Works fine for anything. 1/9 won't work for 70gr tsx and some other heavier rounds thay are the cream of the crop in 5.56