AR ammo question
If a lower on an AR is marked 5.56 - 223, would it be safe to shoot 556 in that rifle? There's no markings on the barrel. Factory DPMS.
I've read where 223 barrels are tested at 63,000 psi and 556 barrels are tested to 80,000. If true, would guess the mfg and the dealer selling the rifle would be liable for any damage while firing 556 ammo since the barrel might not meet the 556 standard.
Your thoughts.
I've read where 223 barrels are tested at 63,000 psi and 556 barrels are tested to 80,000. If true, would guess the mfg and the dealer selling the rifle would be liable for any damage while firing 556 ammo since the barrel might not meet the 556 standard.
Your thoughts.
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DPMS says
"Yes, despite external dimensions being identical, 5.56 NATO ammunition is a higher pressure round than commercial .223. If your rifle is chambered in .223 only .223 should be used as using .556 NATO can create an unsafe high pressure condition. If your rifle is chambered in 5.56 NATO it is safe to fire both .223 and 5.56 NATO.
The specific chambering of the rifle is stamped on the bottom side of the barrel in front of the gas block/front sight."
If your barrel is not marked, then you should either
1. Stick to .223.
2. Ask DPMS what you have.
3. Load and go, the difference is not as great as it is made out to be.0 -
Thank you. 0 -
quote:I've read where 223 barrels are tested at 63,000 psi and 556 barrels are tested to 80,000. If true, would guess the mfg and the dealer selling the rifle would be liable for any damage while firing 556 ammo since the barrel might not meet the 556 standard.
Well, yes and no.
First of all, almost all AR style rifles now use the 5.56 chamber, or some 5.56-acceptable hybrid chambered designed for increased accuracy (ie the Wylde type chamber). Chances are good that's what you have, whether you know it or not.
For example, *EVERY* 223 type rifle currently listed by DPMS on its website is listed as .223/5.56. Yours is probably perfectly fine with 5.56.
To know for sure, the specific acceptable caliber is, by industry standard, stamped on the barrel. Take a look and see if you can find it. If you CANNOT, call DPMS, tell them what you have (they will want the model number, and likely want the serial #), and ask them if 5.56 is OK. I'd be pretty surprised if they said "no", but whatever they say, or whatever you find on the barrel, please come back and post it here.
Next, most commercially loaded ammo isn't loaded to true full max 5.56 pressure, despite how its labelled. So firing this probably wouldn't "grenade" the gun, even if fired in the wrong chamber. I think a bigger concern is that higher than acceptable pressures will cause the primer to back out of .223 ammo, causing it to drop into the gun action, locking it up. That's "OK" at the range (maybe. . .if you're not competing), not so OK during a firefight!
As to liability, despite the often stated concern about firing 5.56 ammo in .223 guns, I'm not aware of any examples where someone has actually "blown up" a .223 gun with 5.56 factory ammo. I think manufacturers are MORE than aware of this issue, and that's the primary reason why most of the guns are 223/556 now.
I don't want to speculate too much about hypotheticals, but I actually have seen a "blown up" AR (from a too hot reload) and the shooter wasn't actually injured. If this did happen, the manufacturer would probably graciously spot you a new gun. Proving manufacturer liability, I think, could be tough if you were using the wrong ammo in your gun. What did the user manual say? Well. . .what do you mean you didn't read it? Etc. [;)] You could TRY, but I think by far the smarter thing is just to use the right ammo for you gun, ear, and eye protection!
Edit: This is a pretty serious essay on said topic, with actual testing. http://www.luckygunner.com/labs/5-56-vs-223/
Skipping to bottom line, this author did the testing and did NOT see dangerous increase in pressure firing actual 556 ammo through actual 223 guns. As a matter of practice, lots of people DO fire 556 through 223 guns (knowingly or unknowingly) and guns "blowing up" are effectively unheard of. So, this appears to be a case of the theoretical risk exceeding the actual risk.0 -
You're not going to blow up any barrels.
If anything were to let go it would be the locking lugs on bolt and/or barrel.
Since these are the same on both chamberings, it's not an issue.0 -
"There's no markings on the barrel. Factory DPMS."
So, how do you know WHAT it is(other than what the seller told you)?
The markings on the lower MEAN NOTHING.0
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