What is the differences between .223 and 5.56 ammo ?
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AR-15 Ammo
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Candrews86
Member
5.56 is a higher pressure, higher velocity round made for military applications. You can shoot .223 in a 5.56 chamber but not vice versa.
Arik
Member
Today if you're buying a modern AR (not one made 35 years ago) you can shot either.
In short: the difference between .223 and 5.56 ammo is pressure; 5.56 is loaded to higher pressure, which is why it's generally considered fine to shoot .223 in an AR specified for 5.56, but not advised to shoot 5.56 if your AR on specs for .223.
Compounding this, barrels built for 5.56 have longer throats than those built for .223, so shooting a higher pressured 5.56 in a shorter-throated .223 barrel further increases overpressure risks.
Compounding this, barrels built for 5.56 have longer throats than those built for .223, so shooting a higher pressured 5.56 in a shorter-throated .223 barrel further increases overpressure risks.
Generally speaking you shouldn't fire large quantities of 5.56 in a barrel marked .223. You are safe firing .223 in a 5.56 barrel. Firing a few 5.56 rounds now and then isn't going to blow up a .223 barrel, but they may cause excessive wear due to the slight differences in the chamber design resulting in slightly higher than normal pressure within the barrel. It's difficult to compare pressure ratings of 5.56 and .223 because they are measured differently. The military has one standard of measurement for 5.56 where SAAMI has a different standard of measurement for .223. However, it is generally accepted that a 5.56 will generate higher pressure in a .223 barrel than will a .223 round. In a 5.56 barrel the differences are negligible due to the longer throat (and often slightly larger bore).
I only buy .223 myself. Why? Because the cost is significantly less than that of 5.56 rounds, and I am cheap.
I only buy .223 myself. Why? Because the cost is significantly less than that of 5.56 rounds, and I am cheap.
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gregintenn
Member
Sort of like a 7.62x51 NATO vs 308 Winchester in reverse.
My take on it: 5.56 is a military designation while 223 Remington is a commercial designation. Cases are the same dimensions. Chambers are slightly different.
My take on it: 5.56 is a military designation while 223 Remington is a commercial designation. Cases are the same dimensions. Chambers are slightly different.
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eyegots2no
Member
I have an input here but I will not swear that I am correct...
1. I keep hearing that 5.56 is higher pressure than .223 and I believe that is incorrect.
2. If you look at the Sierra manual, the loads for bolt guns are hotter than for AR's. If you look at the Cartridges of the World ---in the back and look at the powder and load for the Vietnam era rounds it is not any more that what you see in the bullet company manuals.
With all of this talk---a while back i just went to measure everything myself with what reloading tools I have available and this is what I think is the deal.
3. The old 55 grain 193 bullets has a surface bearing area that was relatively farther forward than many 223 caliber bullets and the M16 chambers were made with a freebore and a long tapered throat.
4. Bolt guns will not have such a freebore and long throat typically, but have commercial rifle throat. The worry was that if you took military rounds and put them in a commercial bolt gun, the rounds may already be jutted into the rifling, hence, a high pressure spike potential.
5. I measured some 1972, and 1980 military rounds, and some reloads of 55 ballistic tips loaded to mag length, and some various factory .223 ammo and the difference was that the military ammo was some 45 to 50 thousanths farther forward (if I remember correctly). On some of the military ammo, ---it was much more---the QC or consistency on the military ammo was quite varied.
6. I saw recently were Dick Treakle in the American Rifleman said the the new 62 grain bullets being so much heavier---so the need for very long throats on the military rifles. I am not sure he knows what he is talking about. The bullets weigh more but that extra bullet is not outside the case, they still have to fit in the magazine---right??. Hence---the extra bullet is deep in the loaded rounds and the exposed portion are as streamlined as the ballistic tips----I have measured them.
7. I have measured recent 55 grain FMJ rounds some even purported to be M193 bullets and they do not have the same configuration as the old military ammo I have measured. They are not as "fat forward" as the old military ammo.
1. I keep hearing that 5.56 is higher pressure than .223 and I believe that is incorrect.
2. If you look at the Sierra manual, the loads for bolt guns are hotter than for AR's. If you look at the Cartridges of the World ---in the back and look at the powder and load for the Vietnam era rounds it is not any more that what you see in the bullet company manuals.
With all of this talk---a while back i just went to measure everything myself with what reloading tools I have available and this is what I think is the deal.
3. The old 55 grain 193 bullets has a surface bearing area that was relatively farther forward than many 223 caliber bullets and the M16 chambers were made with a freebore and a long tapered throat.
4. Bolt guns will not have such a freebore and long throat typically, but have commercial rifle throat. The worry was that if you took military rounds and put them in a commercial bolt gun, the rounds may already be jutted into the rifling, hence, a high pressure spike potential.
5. I measured some 1972, and 1980 military rounds, and some reloads of 55 ballistic tips loaded to mag length, and some various factory .223 ammo and the difference was that the military ammo was some 45 to 50 thousanths farther forward (if I remember correctly). On some of the military ammo, ---it was much more---the QC or consistency on the military ammo was quite varied.
6. I saw recently were Dick Treakle in the American Rifleman said the the new 62 grain bullets being so much heavier---so the need for very long throats on the military rifles. I am not sure he knows what he is talking about. The bullets weigh more but that extra bullet is not outside the case, they still have to fit in the magazine---right??. Hence---the extra bullet is deep in the loaded rounds and the exposed portion are as streamlined as the ballistic tips----I have measured them.
7. I have measured recent 55 grain FMJ rounds some even purported to be M193 bullets and they do not have the same configuration as the old military ammo I have measured. They are not as "fat forward" as the old military ammo.
From what I have read the pressure limit for .223 ammo is stated to
be 50,000, which would be CUP I assume. 5.56 M193 ammo limit is
52,000 and 5.56 M855 ammo is 55,000. The recent article in the
American Rifleman magazine on the search for M855's replacement
confirmed that the 62 gr green tip ammo is loaded to higher pressure
than 55 gr and causes more bore and gun wear. The possible new
round is loaded to even higher pressure and hard on the rifles.
be 50,000, which would be CUP I assume. 5.56 M193 ammo limit is
52,000 and 5.56 M855 ammo is 55,000. The recent article in the
American Rifleman magazine on the search for M855's replacement
confirmed that the 62 gr green tip ammo is loaded to higher pressure
than 55 gr and causes more bore and gun wear. The possible new
round is loaded to even higher pressure and hard on the rifles.
The Great Skeptic
Does your (The?) ammo chamber in your gun?
YES -- pull the trigger
NO -- further investigation required.
Does your (The?) ammo chamber in your gun?
YES -- pull the trigger
NO -- further investigation required.
NJM15
Member
More powerful
To me they are different ,if you alternate rounds you can
readily see ,feel and hear the difference also the 5.56 show a muzzle flash about 8 to 9 inches
To me they are different ,if you alternate rounds you can
readily see ,feel and hear the difference also the 5.56 show a muzzle flash about 8 to 9 inches
