AR Chambered for 556 can shoot 223 ?

[Puma]

This is a newbee as you will see by the question I am asking. But I am a quick lerner......LOL ! I recall reading that a rifle chambered for 556 can also shoot 223. Please shed some light as to whether I am correct. I ordered a DPMS 3G1 and I failed to clarify this.

Any and all information will be gratly appreciated.

[sirveyr]

From the Winchester website, I think?

There are a lot of questions about these two cartridges. Many people think they are identical - merely different designations for commercial and military. The truth is that, although somewhat similar, they are not the same and you should know the differences before buying either cartridge.

* The cartridge casings for both calibers have basically the same length and exterior dimensions.

* The 5.56 round, loaded to Military Specification, typically has higher velocity and chamber pressure than the .223 Rem.

* The 5.56 cartridge case may have thicker walls, and a thicker head, for extra strength. This better contains the higher chamber pressure. However, a thicker case reduces powder capacity, which is of concern to the reloader.

* The 5.56mm and .223 Rem chambers are nearly identical. 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.

Before buying either of these two types of ammunition, always check your gun to find what caliber it is chambered for, then buy the appropriate ammunition. Most 5.56mm rounds made have full metal jacket bullets. Performance bullets - soft points, hollow points, Ballistic Silvertips, etc. - are loaded in .223 Rem cartridges. Firing a .223 Rem cartridge in a 5.56mm-chambered gun is safe and merely gives you slightly reduced velocity and accuracy. However we do not recommend, nor does SAAMI recommend, firing a 5.56mm cartridge in a gun chambered for the .223 Rem as the shorter leade can cause pressure-related problems.

Edited November 15, 2011 by sirveyr

[sirveyr]

Controlled pair post.

Edited November 15, 2011 by sirveyr

[warpspeed]

This is a newbee as you will see by the question I am asking. But I am a quick lerner......LOL ! I recall reading that a rifle chambered for 556 can also shoot 223. Please shed some light as to whether I am correct. I ordered a DPMS 3G1 and I failed to clarify this.

Any and all information will be gratly appreciated.

Yes. 223rem in 5.56NATO is GTG.

[Flatland Shooter]

Would throating a .223 chamber out to .164" make this gun OK to use with 5.56 rounds or is there more to it?

I have several in 5.56 but only one in .223 and don't really like the multiple ammo issue.

Thanks.

Bill

[Alaskapopo]

Would throating a .223 chamber out to .164" make this gun OK to use with 5.56 rounds or is there more to it?

I have several in 5.56 but only one in .223 and don't really like the multiple ammo issue.

Thanks.

Bill

You could just shoot .223 ammo in all your guns. Most ammo out there is .223 spec not 5.56. You have to look for 5.56 ammo.

Pat

[gerritm]

This is a newbee as you will see by the question I am asking. But I am a quick lerner......LOL ! I recall reading that a rifle chambered for 556 can also shoot 223. Please shed some light as to whether I am correct. I ordered a DPMS 3G1 and I failed to clarify this.

Any and all information will be gratly appreciated.

I have a DPMS 3g and just to verify checked the DPMS website and the 3G1 is a 5.56 chamber so you will be able to shoot either .223 or 5.56. Good thing cause I just ordered 900 rounds of 5.56.

Highlighting the new lightweight rifle is the exceptionally accurate, 18” (black) Teflon®-coated MK-12 stainless steel heavy barrel, chambered in 5.56 NATO with a 1x8 twist and finished with the muzzle stabilizing Miculek Compensator.

[Flatland Shooter]

Would throating a .223 chamber out to .164" make this gun OK to use with 5.56 rounds or is there more to it?

I have several in 5.56 but only one in .223 and don't really like the multiple ammo issue.

Thanks.

Bill

You could just shoot .223 ammo in all your guns. Most ammo out there is .223 spec not 5.56. You have to look for 5.56 ammo.

Pat

That would work but I stocked up (several thousand rounds) of Federal XM193. Got more than I will shoot in the next 5 years.

Bill

[twodownzero]

Would throating a .223 chamber out to .164" make this gun OK to use with 5.56 rounds or is there more to it?

I have several in 5.56 but only one in .223 and don't really like the multiple ammo issue.

Thanks.

Bill

You could just shoot .223 ammo in all your guns. Most ammo out there is .223 spec not 5.56. You have to look for 5.56 ammo.

Pat

That would work but I stocked up (several thousand rounds) of Federal XM193. Got more than I will shoot in the next 5 years.

Bill

Sell it. That stuff is worth a fortune!

[Flatland Shooter]

Would throating a .223 chamber out to .164" make this gun OK to use with 5.56 rounds or is there more to it?

I have several in 5.56 but only one in .223 and don't really like the multiple ammo issue.

Thanks.

Bill

You could just shoot .223 ammo in all your guns. Most ammo out there is .223 spec not 5.56. You have to look for 5.56 ammo.

Pat

That would work but I stocked up (several thousand rounds) of Federal XM193. Got more than I will shoot in the next 5 years.

Bill

Sell it. That stuff is worth a fortune!

Not gonna happen. I survived (barely) when primers were hard to get a few years ago. Decided at that time to stockpile anything that I felt I really wanted. As I use, I replace it.

Bill

[A38337]

Per SAMMI, firing 5.56 ammo in .223 chamber is an unsafe practice. In addition ao the dimensional differences between the two cartridges, 5.56 has higher pressure than .223.

There have been many instances of barrels being marked as 5.56 Nato when in fact they are not.

It would be worth one's time to use chamber gauges to make sure of what you have.

I use 5.56 ammo occasionally, so I have 5.56 chambers in all my carbines.

I own 5.56 Nato GO, NO GO, and FIELD gauges and for guys in the Marysville/Everett WA areas, if you want to use my gauges to check your chamber, PM me.

Ned Christiansen (michiguns.com) offers a chamber reamer for the purpose of modifying .223 Rem chambers to 5.56 Nato dimensions.

(no affilition with him)

Edited November 15, 2011 by A38337

[mpeltier]

Per SAMMI, firing 5.56 ammo in .223 chamber is an unsafe practice. In addition ao the dimensional differences between the two cartridges, 5.56 has higher pressure than .223.

There have been many instances of barrels being marked as 5.56 Nato when in fact they are not.

It would be worth one's time to use chamber gauges to make sure of what you have.

I use 5.56 ammo occasionally, so I have 5.56 chambers in all my carbines.

I own 5.56 Nato GO, NO GO, and FIELD gauges and for guys in the Marysville/Everett WA areas, if you want to use my gauges to check your chamber, PM me.

Ned Christiansen (michiguns.com) offers a chamber reamer for the purpose of modifying .223 Rem chambers to 5.56 Nato dimensions.

(no affilition with him)

Go, No Go, and Field gauges are for checking headspace. Those gauges do not generally go beyond the shoulder of the chamber. They wont do much good indicating the amount of leade.

Edited November 16, 2011 by mpeltier

[Mark Gale]

Per SAMMI, firing 5.56 ammo in .223 chamber is an unsafe practice. In addition ao the dimensional differences between the two cartridges, 5.56 has higher pressure than .223.

There have been many instances of barrels being marked as 5.56 Nato when in fact they are not.

It would be worth one's time to use chamber gauges to make sure of what you have.

I use 5.56 ammo occasionally, so I have 5.56 chambers in all my carbines.

I own 5.56 Nato GO, NO GO, and FIELD gauges and for guys in the Marysville/Everett WA areas, if you want to use my gauges to check your chamber, PM me.

Ned Christiansen (michiguns.com) offers a chamber reamer for the purpose of modifying .223 Rem chambers to 5.56 Nato dimensions.

(no affilition with him)

The dimensional differences are only internal (thicker web and case wall). The term "chamber guage" is a bit of a misnomer because it can't be used to identify which chamber your rifle has. It only gives you information on head space. Two similar rifles could have the same head space dimension but different throat dimensions.

[A38337]

Good points. Thanks.

Stoney Point makes a gauge you can be used along with a RCBS case mic that will allow one to determine distance to the rifling.

Edited November 16, 2011 by A38337