.223 vs 5.56?

[langss]

Initially I never actually kept track of what I shot out of which AR because it was so inexpensive I never considered reloading for it. Then I got a Winchester chambered in .223 to use the brass from the AR's in. I never paid attention to whether it was 5.56 or .223 I was shooting out of it, and never noticed any signs of over pressure or anything else, that is until I bought the Remington XP 100 in .223. The first shot told me something was wrong when I had to open the bolt with a block of wood. Obvious sign of over pressure. But me being me I thought it was perhaps just the brand of ammo and pressed on with a different brand with the same result. So I tried another brand and had no sign of over pressure. I now know what I did and I will say that Remington builds a pretty tough gun to withstand what amounts to serious over pressure loads and still shoot just fine.The point being that if it says 5.56 on your barrel your good to use either. If it says .223 on your barrel....stick with .223 or carry a block of wood to open your bolt.

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[jmoore]

...Remington XP 100 in .223. The first shot told me something was wrong when I had to open the bolt with a block of wood. Obvious sign of over pressure. But me being me I thought it was perhaps just the brand of ammo and pressed on with a different brand with the same result. So I tried another brand and had no sign of over pressure. I now know what I did and I will say that Remington builds a pretty tough gun to withstand what amounts to serious over pressure loads and still shoot just fine.The point being that if it says 5.56 on your barrel your good to use either. If it says .223 on your barrel....stick with .223 or carry a block of wood to open your bolt.

The wood block works up to a point. But I've seen more than one 700 bolt minus it's handle after the braze fails! One was in fact a .223. But in that case it was the owner's fault for getting too aggresssive with his loads. Blew the entire case head off BEFORE he proceded to further mangle the bolt. Funnily enough, the rifle was later returned to service with the same bolt after some major rework including the addition of a SAKO type extractor and a silver soldered ring replacing the ruined area surrounding the bolt face...

[browningautorifle]

Blew the entire case head off

But that was the reloader's fault. I still maintain no problem.

[jmoore]

But that was the reloader's fault. I still maintain no problem.

Noted!

...it was the owner's fault for getting too aggresssive with his loads.

Nor was he shooting 5,56 even though the rifle had some sort of wretched M16 magazine conversion which reduced the thickness of the feed area behind the lower locking lug. The point being that bolt handles on modern Remingtons aren't as stout as the old timey stuff.

langss was the one with the cautionary example which seems not out of the question.

[vintage hunter]

I had a similar experience to the one JM describes in post 19. Mine involved a Rem. 700 Varmint in 6mm Remington and it was caused by defective factory ammo but I digress.
I also have a Howa 1500 bolt gun and 99% of the ammo I shoot in it is surplus M193 ball. I came into a 5 gallon bucket of mixed(foreign and domestic manufacture) 5.56 M193 ammo at a gun years ago and separated according to headstamp, it's about gone now but I never once had any kind of problems related to the use of 5.56 ammo in a .223 chamber.

[DaveN]

But that was the reloader's fault. I still maintain no problem.

I will after reading all this experience go with better safe then sorry.
Rifles marked .223 get .223. Rifles marked 5.56 get 5.56 and or .223. Rifles marked 5.56/.223 I'll use either or at this rate what I can get my hands on.
But in the case of life and death....whatever I can chamber (5.56 or .223).
Thanks again for making it interesting as usual.