Please comment if you know if I buy a 5.56 upper will it shoot223 accurate
- Thread starter nbsrtue
- Start date
UtahShooter
Active member
Yes it will. The difference is in the case and not the projectiles. You will be fine.
223 and 556 have different chambers.
556 is the military chamber and is very "sloppy" compared to a 223 chamber, this is for reliability in the field, and to deal with war time mass produced ammo which does not always hold to the tightest specs.
You can shoot 223 out of 556 chambers but the accuracy will not be as good as it could be when using commercial ammo in a 223 chamber.
You should not try to run 556 ammo in a 223 chamber, for a number of reasons.
There is a happy medium, the 223 wylde chamber, this chamber will allow you to shoot both safely, and shoot 223 accurately.
556 is the military chamber and is very "sloppy" compared to a 223 chamber, this is for reliability in the field, and to deal with war time mass produced ammo which does not always hold to the tightest specs.
You can shoot 223 out of 556 chambers but the accuracy will not be as good as it could be when using commercial ammo in a 223 chamber.
You should not try to run 556 ammo in a 223 chamber, for a number of reasons.
There is a happy medium, the 223 wylde chamber, this chamber will allow you to shoot both safely, and shoot 223 accurately.
Yote Yoda USMC
New member
2nd that. Good Info here.Originally Posted By: Kies_firearms223 and 556 have different chambers.
556 is the military chamber and is very "sloppy" compared to a 223 chamber, this is for reliability in the field, and to deal with war time mass produced ammo which does not always hold to the tightest specs.
You can shoot 223 out of 556 chambers but the accuracy will not be as good as it could be when using commercial ammo in a 223 chamber.
You should not try to run 556 ammo in a 223 chamber, for a number of reasons.
There is a happy medium, the 223 wylde chamber, this chamber will allow you to shoot both safely, and shoot 223 accurately.
556 is the military chamber and is very "sloppy" compared to a 223 chamber, this is for reliability in the field, and to deal with war time mass produced ammo which does not always hold to the tightest specs.
You can shoot 223 out of 556 chambers but the accuracy will not be as good as it could be when using commercial ammo in a 223 chamber.
You should not try to run 556 ammo in a 223 chamber, for a number of reasons.
There is a happy medium, the 223 wylde chamber, this chamber will allow you to shoot both safely, and shoot 223 accurately.
5.56 barrel here just so I could shoot bulk 5.56 plinking ammo. Mine does very respectable with .223 ammo, with 100rd bulk American Eagle it does about 1.5moa, with good Hornady loads it's pretty easy to keep it under moa. I will be tightening those up soon though, my stock trigger is absolutely terrible. I did connect with a red fox at 240yds last night, still looking for it though...
Widow maker 223
Well-known member
5.56 is loaded to higher pressures. Thats why its a no no to shoot it in a .223
willy1947
Active member
The Difference Between 223 Rem and 5.56 Military Cartridges
There is a general misperception by the shooting public that the 223 Rem and 5.56 Military cartridges are
identical – just different designations for commercial and military – and can routinely be interchanged. The
fact however is that, although somewhat similar, they are not the same.
• The cartridge casings of each have basically the same length and exterior dimensions.
• Mil Spec 5.56 ammo typically has higher velocity and chamber pressure than the 223 Rem.
• The 5.56 cartridge case may have a thicker sidewall and a thicker head - to better withstand the
stresses generated by the higher chamber pressures. This, however, reduces the powder capacity of
the case - which is of concern to the reloader.
• The 5.56mm and 223 Rem. chambers are similar but not identical. The difference is in the “Leade”.
Leade is defined as a portion of the barrel directly in front of the chamber where the rifling has been
conically removed to allow room for the seated bullet. This portion of the chamber is 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 – compared to 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 Arms and
Ammunition Manufacturers Institute) to be an unsafe ammunition combination and is listed in the
“Unsafe Arms and Ammunition Combinations” Section of the SAAMI Technical Correspondent’s
Handbook. It clearly states; “In firearms chambered for 223 Rem – do not use 5.56 Military cartridges.”
Federal Cartridge is a member of SAAMI and supports this position.
• Federal’s XM193 packaging currently has a warning that states “For use in standard 5.56 Chambers.
Do not use in non-standard 5.56 chambers.” This warning is also listed on the XM193 Product
Specification Sheet. Winchester also has a similar warning on their USA brand 5.56 ammunition
packaging: “Use only in firearms in good condition designed and chambered by firearm manufacturer
specifically for this 5.56 ammunition and so marked on the firearm.”
• It is our understanding that commercially available AR15’s and M16’s – although some are stamped 5.56
Rem on the receiver – are manufactured with .223 chambers. Our advice however should be that
it is the customer’s responsibility to know what their firearm is chambered for and choose their ammo
accordingly.
There is a general misperception by the shooting public that the 223 Rem and 5.56 Military cartridges are
identical – just different designations for commercial and military – and can routinely be interchanged. The
fact however is that, although somewhat similar, they are not the same.
• The cartridge casings of each have basically the same length and exterior dimensions.
• Mil Spec 5.56 ammo typically has higher velocity and chamber pressure than the 223 Rem.
• The 5.56 cartridge case may have a thicker sidewall and a thicker head - to better withstand the
stresses generated by the higher chamber pressures. This, however, reduces the powder capacity of
the case - which is of concern to the reloader.
• The 5.56mm and 223 Rem. chambers are similar but not identical. The difference is in the “Leade”.
Leade is defined as a portion of the barrel directly in front of the chamber where the rifling has been
conically removed to allow room for the seated bullet. This portion of the chamber is 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 – compared to 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 Arms and
Ammunition Manufacturers Institute) to be an unsafe ammunition combination and is listed in the
“Unsafe Arms and Ammunition Combinations” Section of the SAAMI Technical Correspondent’s
Handbook. It clearly states; “In firearms chambered for 223 Rem – do not use 5.56 Military cartridges.”
Federal Cartridge is a member of SAAMI and supports this position.
• Federal’s XM193 packaging currently has a warning that states “For use in standard 5.56 Chambers.
Do not use in non-standard 5.56 chambers.” This warning is also listed on the XM193 Product
Specification Sheet. Winchester also has a similar warning on their USA brand 5.56 ammunition
packaging: “Use only in firearms in good condition designed and chambered by firearm manufacturer
specifically for this 5.56 ammunition and so marked on the firearm.”
• It is our understanding that commercially available AR15’s and M16’s – although some are stamped 5.56
Rem on the receiver – are manufactured with .223 chambers. Our advice however should be that
it is the customer’s responsibility to know what their firearm is chambered for and choose their ammo
accordingly.
willy1947
Active member
Originally Posted By: UtahShooterYes it will. The difference is in the case and not the projectiles. You will be fine. Actually the difference is in the chamber
a rifle chambered for 5.56 nato has a longer lead than a rifle chambered for .223 Remington. When it comes to the ammo, a 5.56 nato round is loaded to 62000 psi. a .223 Remington round is only loaded to 55000 psi. the actual case dimensions are identical. the nato round is simply loaded hotter.
a shooter should not see any accuracy issues shooting .223 Remington in a nato chamber. shooting a nato round in a Remington chamber will damage the rifle.
a rifle chambered for 5.56 nato has a longer lead than a rifle chambered for .223 Remington. When it comes to the ammo, a 5.56 nato round is loaded to 62000 psi. a .223 Remington round is only loaded to 55000 psi. the actual case dimensions are identical. the nato round is simply loaded hotter.
a shooter should not see any accuracy issues shooting .223 Remington in a nato chamber. shooting a nato round in a Remington chamber will damage the rifle.
Evil_Lurker
New member
Quote:• The 5.56 cartridge case may have a thicker sidewall and a thicker head - to better withstand the
stresses generated by the higher chamber pressures. This, however, reduces the powder capacity of
the case - which is of concern to the reloader.
I've never found one yet, out of thousands of cases. It IS possible that somebody, somewhere, makes them though.
Weigh a couple of empty cases. If they weigh the same as commercial, they're obviously not thicker or have a reduced capacity.
Quote:• It is our understanding that commercially available AR15’s and M16’s – although some are stamped 5.56
Rem on the receiver – are manufactured with .223 chambers. Our advice however should be that
it is the customer’s responsibility to know what their firearm is chambered for and choose their ammo
accordingly.
Yeah, the barrel is stamped with the chamber info. The receiver stamp is useless, it could have a 50 Beowulf upper on it and show 5.56 NATO on the receiver.
stresses generated by the higher chamber pressures. This, however, reduces the powder capacity of
the case - which is of concern to the reloader.
I've never found one yet, out of thousands of cases. It IS possible that somebody, somewhere, makes them though.
Weigh a couple of empty cases. If they weigh the same as commercial, they're obviously not thicker or have a reduced capacity.
Quote:• It is our understanding that commercially available AR15’s and M16’s – although some are stamped 5.56
Rem on the receiver – are manufactured with .223 chambers. Our advice however should be that
it is the customer’s responsibility to know what their firearm is chambered for and choose their ammo
accordingly.
Yeah, the barrel is stamped with the chamber info. The receiver stamp is useless, it could have a 50 Beowulf upper on it and show 5.56 NATO on the receiver.
RowdyRawhide
New member
Originally Posted By: Evil_Lurker