Shooting 5.56 in a .223 Chamber

[4 eyed six shooter]

I've had more than a few people in the shop ask about the dangers of shooting 5.56 military ammo in a rifle chambered for .223. Here is a good piece on the subject. Bottom line is don't shoot 5.56 in your rifle that is chambered for .223.
http://www.winchester.com/lawenforce...spx?storyid=11

Good shooting, John K.

[Marlin]

Good information, John.

Thanks for bringing it to our atttention.

[ironsight65]

Thanks for the post. I always thought they were the same.

[Glocker]

Have there been any known instances of damaged rifles or injury associated with firing 5.56 in rifles chambered for .223?

[inplanotx]

I have heard of two instances at our range where a shooter with a 223 was using military brass (5.56) and hot rodding them. The pierced primers resulting from this stupidity caused burns from the gas exhaust through the action. It is dangerous.

[CountryGunsmith]

And here's the deal.

The SAAMI bulletin came out in 1979. There are a few differences between the chamber specifications of .223 Remington and 5.56mm NATO. The difference is in the chamber throat. The military chamber has about .080" longer leade (or throat/freebore). The problem is that if you feed 5.56mm NATO cartridges into a tightly-throated .223 Remington chamber you can jam the bullet nose into the start of the rifling which can increase chamber pressures. Some 5.56mm is loaded hotter than commercial .223 as well (but still well within safety margins of any commercially built rifle), most notably imported ammunition.

To my knowledge, this has only resulted in some blown-out primers on an anecdotal basis with known tightly-chambered guns.

The fact is that the differences between COMMERCIAL .223 chambers exceed the difference between the SAAMI .223 and 5.56mm. CZ vs Remington 700 vs Ruger vs whoever all are throated a little differently. Check with your manufacturer to see how your rifle is throated, or have a chamber cast made to include the throat. You'll find that most manufacturers have increased the throat on their rifles to accomodate the longer bullets currently in vogue, and thus have largely eliminated the problem. Earlier rifles chambered in .223 with the slow twist rate specifically for the 50-52gr bullets are the most likely to have the short throat.

[Glocker]

Originally Posted by inplanotx

I have heard of two instances at our range where a shooter with a 223 was using military brass (5.56) and hot rodding them. The pierced primers resulting from this stupidity caused burns from the gas exhaust through the action. It is dangerous.

I was referring to factory ammo, rather than handloads.

[LIKTOSHOOT]

Blah.......Blah.......................................blah



LTS

[ibtrukn]

I think Phishie rams 458's thru his dubble duces, thas Y he gets all them tree rat kills (he says)

[inplanotx]

Originally Posted by Glocker

I was referring to factory ammo, rather than handloads.

So called "factory" ammo is .223 Remington, not 5.56mm. The 5.56 is MILITARY ammo and can usually only be had as surplus or cheap imported military ammo. I have never seen any commercially SOLD, boxed and labeled 5.56mm that was not military to begin with. Someone correct me if I am wrong.

[Glocker]

Originally Posted by inplanotx

So called "factory" ammo is .223 Remington, not 5.56mm. The 5.56 is MILITARY ammo and can usually only be had as surplus or cheap imported military ammo. I have never seen any commercially SOLD, boxed and labeled 5.56mm that was not military to begin with. Someone correct me if I am wrong.

Perhaps instead of calling it "factory" I should have said ammo that hadn't been hot-rodded since the cause of the pierced primers and subsequent injury was likely due to the hot handloads, and not simply the use of 5.56 in a .223. Would it have happened had the 5.56 not been hot-rodded? I don't know.

I'm not advocating the use of 5.56 in .223....just trying to learn if anyone knows of a case of a rifle or shooter actually being damaged or injured due to doing so.

[ryan_marine]

If someone can tell me different please do so.
We were tought, told, and I have seen it shot across a crony, that the m16 using 5.56mm were in the 3250fps range.

My 223 700VLS shoot all day in the 3300fps and that is with a mild load. This is with the same weight of bullet.

Can some one tell my why that it is said the 5.56 round are to much velocity and preasure. I have never heard of 5.56 too much for 223 but I have been told that some 223s are too much for the ol M16 to handle.

Ray

[inplanotx]

Originally Posted by ryan_marine

If someone can tell me different please do so.
We were tought, told, and I have seen it shot across a crony, that the m16 using 5.56mm were in the 3250fps range.

My 223 700VLS shoot all day in the 3300fps and that is with a mild load. This is with the same weight of bullet.

Can some one tell my why that it is said the 5.56 round are to much velocity and preasure. I have never heard of 5.56 too much for 223 but I have been told that some 223s are too much for the ol M16 to handle.

Ray

Your question is answered above by CG and read the original article from the first post!