Stupid .223/5.56 question

[Rick Courtright]

Hi,

Discussion over coffee yesterday turned to why manufacturers don't just automatically chamber most or all their rifles to handle both those cartridges (later the .308/7.62x51 combo came up, too.) One of the fellows involved has two Savages, one .223, one .308, and was curious considering the current ammo situation. He called Savage to ask about what he could feed the .223 and they told him NO on using 5.56 ammo. He can find 5.56 now and again, so he's been buying it and trading w/ a buddy for .223. Buddy can shoot both in his AR--but now HE's running short on .223s. Uh, oh!

Dealing w/ the pressure differences seems like an easy enough engineering challenge, but is there some other reason as well, like accuracy, poor case life due to the ever so slight chamber/leade differences, or ???

I don't shoot any of those four cartridges, and didn't know the answers but promised I'd ask and relay what I could learn from you guys. Thanks!

Rick C

 

[Busterswoodshop]

Here is a pretty good article that explains it pretty well. http://www.gundigest.com/223-vs-5-56

There is also a good article about it in the new Gun Digest 67th edition.
There is a reamer you can purchase that will ream your chamber out to 5.56
Both articles talk about the reamer and how it works.

 

[gramps]

I have .223, and .308. I shoot both incarnations in their respective guns. No problems. If you're hand loading at the top end then you may have a problem, but by then the brass should be fire formed to your platform. Pretty much academic stuff, and theoretical musings. IMO making a mountain of a mole hill.
gramps

 

[Mobuck]

This is only my opinion but this opinion is based on shooting 5.56 M193 in at least 1/2 dozen .223 rifles. In my specific rifles, the M193(55 grain FMJBT bullets) cause no problems except in an NEF single shot(it shows some serious signs of high pressure with 5.56 ammo).
The bigger problems arise when the longer, heavier 62 grain M855 is used in the shorter throat of the .223.

 

[Snake45]

Hard to imagine a Savage 110 not being able to handle 5.56. It's a VERY strong action.

Also, this whole .223/5.56 thing has only been well known for the last decade or so. Before that, people were shooting USGI 5.56 "surplus" ammo in every kind of civilian .223 rifle ever made for four decades and I never heard of any problems or one blowing up. :?

 

[anachronism]

It's not a matter of action strength, the issue is in the chamber throating. The civilian .223 has shorter throats, which can raise chamber pressures with 5.56 spec ammo to potentially dangerous levels. The throat can be lengthened in .223 guns, but you can experience a degradation in accuracy by lengthening the throat. This is very likely why Savage doesn't chamber their rifles in 5.56, people expect a certain level of accuracy from their rifles, and they cannot guarantee satisfactory accuracy when .223 ammo is fired in a 5.56 military spec chamber. Individual rifles may vary of course, but also remember that 5.56 spec ammo isn't really noted for accuracy in the first place. Customer satisfaction is what pays the bills.