.223/5.56 Marked Lowers...?

[wake.joe]

Deleted

[Captains1911]

delete

[Captains1911]

The OP asked about markings on the lower, on that much we can agree.

Then you made an incorrect statement about the barrel, I corrected you, and you are having a hard time accepting it.

Move on...

You're right dude, from now on we must all disregard barrel markings, and accept the fact that there is absolutely no way to tell what chamber you have. Hell, I'm not even sure if my .45 pistols that have ".45 ACP" marked on the barrels are actually .45s

[rmecapn]

Not really, it only matters how the chamber was actually reamed!

Then exactly how do I determine what chamber I have on my AR?

[Captains1911]

Then exactly how do I determine what chamber I have on my AR?

According to "Omega", you better call up your reamer and ask.

The correct answer is you look at the markings on the barrel.

[Iraqgunz]

Without starting a pissing contest you are incorrect. Bushmaster barrels are marked BMP 5.56, but the chambers are in fact not 5.56. I believe that some other makers do the same. The only way to know for sure is to rely on the manufacturers reputation or use a 5.56 chamber reamer from M-guns.

According to "Omega", you better call up your reamer and ask.

The correct answer is you look at the markings on the barrel.

[Iraqgunz]

Who makes your barrel or upper? That says alot. Colt, LMT, Daniel Defense and I believe Sabre all use 5.56 chambers. Noveske has a modified 5.56 chamber.

Oly Arms, Bushmaster, DPMS, and a few others that don't come to mind generally do not have 5.56 chambers.

Then exactly how do I determine what chamber I have on my AR?

[Omega_556]

Then exactly how do I determine what chamber I have on my AR?

You can use Cerrosafe to make a cast of your chamber. Then you measure the casting to know exactly what chamber is in your weapon.

Here is a link to the dimensions from .223 vs 5.56 from AR15barrels

Reamers are available from Ned Christiansen of Michiguns LTD. in the event you don't have a true 5.56 chamber.

[rmecapn]

Without starting a pissing contest you are incorrect. Bushmaster barrels are marked BMP 5.56, but the chambers are in fact not 5.56.

Then that leaves Bushmaster (and any other manufacturer who does the same) open for some serious liability.

I know Ned's reamer has pulled shavings from all sorts of manufacturers' chambers. I'm not going to debate that issue. But I believe that C1911's point was that the manufacturer is identifying the chamber as 5.56. Whether they actually QC the chamber to insure it meets those specs is another matter.

[rmecapn]

You can use Cerrosafe to make a cast of your chamber. Then you measure the casting to know exactly what chamber is in your weapon.

Here is a link to the dimensions from .223 vs 5.56 from AR15barrels

Reamers are available from Ned Christiansen of Michiguns LTD. in the event you don't have a true 5.56 chamber.

And you've done that to each of your AR's?