[Muliemaster]

Originally Posted by bigjim

A 5.56 rifle has a longer throat than a 223 rifle. The shoulder of the 5.56 case is at a different angle and will seal in a 5.56 barrel better. The 5.56 is loaded hotter and may or may not have a smaller inside diamiter because of more material in the case (hotter load).

You do not want to use 5.56 in a 223 rifle, you will burn the barrel out.

Jim

You will not burn the barrel out either.

[Txhillbilly]

Originally Posted by bigjim

You do not want to use 5.56 in a 223 rifle, you will burn the barrel out.

Jim

Where the hell did you here this? That is total BS.

It's a fact that most 5.56 loads have higher chamber pressures than a 223 load,but that will not cause your barrel to burn out the throat any faster.
Besides,it takes thousands of rounds out of a 223/5.56 caliber barrel before it will erode the throat enough to need a new barrel,and most people don't shoot their guns that much.

I've been shooting 5.56/223's for over 30yrs,and have never seen a 223 caliber rifle damaged from shooting a 5.56 x 45 round.
Now I will say if your 223 has a tight chamber,I'd probably try not to shoot 5.56 rounds thru it,as the higher pressures can cause damage to the bolt head,extractors,etc or cause the bolt to be hard to open.

[Muliemaster]

Originally Posted by Txhillbilly

Where the hell did you here this? That is total BS.

It's a fact that most 5.56 loads have higher chamber pressures than a 223 load,but that will not cause your barrel to burn out the throat any faster.
Besides,it takes thousands of rounds out of a 223/5.56 caliber barrel before it will erode the throat enough to need a new barrel,and most people don't shoot their guns that much.

I've been shooting 5.56/223's for over 30yrs,and have never seen a 223 caliber rifle damaged from shooting a 5.56 x 45 round.
Now I will say if your 223 has a tight chamber,I'd probably try not to shoot 5.56 rounds thru it,as the higher pressures can cause damage to the bolt head,extractors,etc or cause the bolt to be hard to open.

Thank you, i have tried to say this 3 times now, what a damn mess of mis info here, the 5.56 will not hurt a damn thing in a 223 ,or vise versa. This has been debated over an over an over till the cows come home. The pressure diff between the 2 is not enough to hurt any damn thing.

[dirtysancho]

Thanks for the info guys I'm calling BS on the vendor in that he wanted to make an extra buck, went to another store found one with a heavy barrel , DPMS AR-15

[Muliemaster]

Originally Posted by dirtysancho

Thanks for the info guys I'm calling BS on the vendor in that he wanted to make an extra buck, went to another store found one with a heavy barrel , DPMS AR-15

Yes thats all he wanted, why sell you cheaper mil spec when he can get ya for premi ammo cost

[Durangokid]

You won't burn the barrel out. But the pressure difference can exceed 50,000 CUPs or 20,000 CUPs over a .223 Remington. The pressure is taken from the side of the 5.56 Ctg. The chamber wall pressure is a concern due to the reduced inside deminsions of the 5.56. Shooting a 5.56 in a tight bolt action rifle with a .223 chamber can damage extractors.

[303tom]

According to the official Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives (C.I.P.) guidelines the .223 Remington case can handle up to 430 megapascals (62,366 psi) piezo pressure. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers. This is equal to the NATO maximum service pressure guideline for the 5.56x45mm NATO cartridge.

[alsaqr]

What 303tom said.

There is a difference in the length of the freebore (leade). i've been shooting milsurp ammo in .223 chambers since 1968 when i had a .222 Sako re-chambered for .223. Since then i've fired hundreds of thousands of military rounds in my .223 rifles.

The problem comes when handloaders use long for caliber heavy bullets in .223 chambers. If they are not careful about OAL pressure will go up.

[beatnutzz]

To add to this thread,
The 5.56 Nato is design for more tolerance for the many different military rifles around the world that chamber it. vs The .223 rem is a sporting cartridge was design truly with the 55 grain bullet in mind to project light weight bullet as fast as it can at less pressure then that of it counter parts at the time of the early days of the AR-15 civilian and M-16, M-16A1 rifles. That round was not yet the NATO round of chose that still preferred the heavier 308 NATO.
The skinny of it is the .223 Remington and 5.56x45mm differ in both maximum pressure and chamber shape. The maximum and mean pressures for some varieties of the 5.56 mm (different cartridge designations have different standards) exceed the SAAMI maximums for the .223 Remington, and the methods for measuring pressures differ between NATO and SAAMI.

[HOSSFLY]

Originally Posted by dirtysancho

Thanks for the info guys I'm calling BS on the vendor in that he wanted to make an extra buck, went to another store found one with a heavy barrel , DPMS AR-15

My last one was a DPMS - I doubt you'll be dissapointed
Bet your buttcakes its marked 223/5.56