Really...how much difference shooting 223 in a 5.56 chamber?

wahoowad

Member
Thinking of a getting a gun with a 5.56 chamber, and I'll probably shoot both 5.56 and 223 in it cuz I have a lot of both. Going forward I prefer to buy 223 and shoot it in it as I shoot more 223 in my other 223 guns. So what's a real world difference in accuracy shooting 223 in a 5.56 chamber?

I prefer a Wylde, but the gun I'm leaning towards doesn't offer the Wylde so just curious the difference I'll experience. If any.

Is there a noticeable difference at 100 yards? 300 yards?
 
every barrel is unique - so its quirks will show itself over time. in that respect its no different than if you got a wylde. only trigger time will prove its individual strong and weak points.


what gun is it that only comes in 5.56?
what twist is the barrel?
how long?
 
I'm not seeing poor accuracy in 223 in the 556. As plant says every barrel is different. Of course part of it is that I handload everything and am not stuck with 556 that historically does not have the best accuracy loadings out there.Of course that also means I'm tailoring the COL to the chamber and that is a plus.

All my AR's are stamped 556 but truth be known lots of manufacturers are sticking WYLDE chambers, or similar types, in them. There is no set in concrete WYLDE dimension as an industry standard that I have seen. For that matter if you bought five various 223 chambered guns if you cast them you might be amazed how inconsistency are. The free bore in some of the 223 bolt guns I own are huge and if you check them the distance to the lands can't be touched with a bullet still in the case. They are longer than a WYLDE so the 223 stamp is no guarantee.

I load to 223 pressures per the manuals and rarely go up to the top end 556 loadings though lately I have been shooting some and the accuracy is holding up. I will probably start cranking up the pressures on some of mine in the future.

Good luck on your search and build.

Greg
 
To follow up with what Greg said, modern 5.56 barrels are made to a much better standard than previous versions. We do not see the difference in accuracy shooting .223's through 5.56 chambers that we used to.

Barrels are made to much better standards, even on the lower end, than they used to be. Yes, you can get a bad one, but that is usually because the barrel MFG doesn't really know what they are doing. A reputable barrel MFG will turn out good barrels with today's technology. And as Greg said they will use the industry standard spec when they chamber the barrel.

Now, 5.56 ammunition is another story. Using mil-surplus ammunition is hit or miss for accuracy regardless of barrels.
 
Originally Posted By: wahoowad...what's a real world difference in accuracy shooting 223 in a 5.56 chamber?

The real world difference in accuracy can vary. However, the real world difference in function is that 223 spec ammo makes less pressure in a 5.56 (and the Wylde chamber) than it does in a SAAMI spec 223 Remington chamber. This is because the 5.56 NATO/223 Wylde chamber uses a longer leade.

Because 223 spec ammo generates less pressure, it causes short stroking in some ARs. To eliminate short stroking with lower pressure ammo, many makers use an overly large port diameter.

Bottom line is, get the AR you want and see what ammo it shoots best because you won't know how accurate or how well it functions until you actually shoot the rifle
 
Last edited:
I shoot both in mine, and with the red dot, I can see no difference. Have no experience as yet with a scope.
 

This is the cut and paste answer,

The difference is in the "Leade". Leade is defined as the portion of the barrel directly in front of the chamber where the rifling has been conically removed to allow room for the seated bullet. It is also more commonly known as the throat. Leade in a .223 Rem chamber is usually .085". In a 5.56mm chamber the leade is typically .162", or almost twice as much as in the 223 Rem chamber.
You can fire .223 Rem cartridges in 5.56mm chambers with this longer leade, but you will generally have a slight loss in accuracy and velocity over firing the .223 round in the chamber with the shorter leade it was designed for.
Problems may occur when firing the higher-pressure 5.56mm cartridge in a .223 chamber with its much shorter leade. It is generally known that shortening the leade can dramatically increase chamber pressure. In some cases, this higher pressure could result in primer pocket gas leaks, blown cartridge case heads and gun functioning issues.
The 5.56mm military cartridge fired in a .223 Rem chamber is considered by SAAMI (Small Arm and Ammunition Manufacturers Institute) to be an unsafe ammunition combination.
 
I don't think I have ever fired a "5.56" round in a 5.56 chamber.

Is a 300 weatherby chambered by weatherby with a long throat a different caliber than a winchester chambered in 300 weatherby with a short throat?

NO.
 
I don't think I have ever fired a "5.56" round in a 5.56 chamber.

Is a 300 weatherby chambered by weatherby with a long throat a different caliber than a winchester chambered in 300 weatherby with a short throat?

NO.
 
No, the caliber might be the same but the pressures are not. Using a 5.56 in a .223 chambered gun can lead to pressures that exceed the safe standards for the .223 chamber. Will it blow up? Maybe not. I have heard plenty of guys say that they shoot them just fine. But metal has a finite stress point. Exceed that and...I just hope I am not next to you when you find out the results.
 
You'll blow primers before you blow your gun in respect to 5.56 in .223. 99.99% it's not an issue. A .223 with 1000 rounds on it is like a .223 wylde. A .223 wylde with 1000 rounds on it is like a 5.56. Throat erosion and such. (generalization, don't blow your gun and blame it on me.)
 
Originally Posted By: wahoowadI was asking about difference in accuracy. Everybody knows there are technical differences in leade and pressures, etc.

While there are a bunch of variables involved with accuracy, generally, 5.56 NATO rounds are FMJ. They are about as accurate as .223 FMJ's, keeping apples to apples. But commercial .223 ammunition that we use for precision shooting or hunting is typically better. Could 5.56 be as accurate? Sure, but we just don't see the same bullet technology being as widely offered by the major ammunition manufacturers.

I build rifles built on the 5.56 chamber just in case one of our customers decides to go and buy a metric truckload of mil surplus ammunition. Then they will be less likely to have a catastrophic failure. Now in terms of accuracy, the barrels seem to do just fine with .223 out of the 5.56 chamber. Not like in the old days when they were really hit or miss. It will vary by manufacturer but if you buy a top quality barrel it will shoot just fine.
 
Simply walking into a room containing a .223 barrel while carrying a single 5.56 round will blow your head off, so beware!
smile.gif
 
This is .223 50 gr V-Max in HMS reman ammo, out of a 5.56 chambered Mossberg MPV. 100 yds.... and I am not the best with a rifle...

QDEA9vw.jpg
 
Back
Top