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9/22/2017 12:11:25 AM
Posted: 12/24/2005 3:21:50 PM EDT
Can anyone suggest a way to identify whether my upper is chambered for .223 or 5.56? I want to know whether or not I can shoot 5.56 ammo safely. I have a DPMS lower marked .223/5.56, but no markings on my upper or barrel that I can see, except for what looks like a small "keyhole" raised graphic near the forward assist. Unfortunately, my upper is of unknown manufacture. It's 16" OAL, M4 profile, chrome lined, unknown twist (also something I would like to somehow identify).
Link Posted: 12/24/2005 3:23:43 PM EDT
Most barrels should be stamped...

Try pulling the handguards and see if the info is there.
Link Posted: 12/24/2005 9:33:30 PM EDT
The keyhole is Cerro forge's mark. Check the barrel for markings, or if you have them, use head space gauges...
Link Posted: 12/24/2005 11:24:50 PM EDT
I pulled the forend and found no marking or stamp, unless it's underneath the barrel nut...

I searched out some headspace gauges for sale online, but I can use a little instruction on how one is used. Am I supposed to finger it into the chamber and look for...something? Can I get away with just trying a 5.56 "GO" gauge to find out if I have a 5.56 chamber?
Link Posted: 12/25/2005 12:03:56 AM EDT
[Last Edit: 12/25/2005 12:09:56 AM EDT by Randall_Rausch]
Link Posted: 1/6/2006 8:12:08 PM EDT
Randall, thanks for the details. I'm interested in collecting the whole gamut of headspace gauges and trying to figure it all out. I've found a couple sites on the web selling the various .223/5.56 GO/NO GO/FIELD gauges for $35-$40 each, so looks like it's gonna add up. If you know where I might find them cheaper, or have any specific recommendations (brands?) please let me know.
Link Posted: 1/7/2006 12:04:32 AM EDT
Link Posted: 1/7/2006 12:40:54 AM EDT
[Last Edit: 1/7/2006 12:42:34 AM EDT by Tweak]
Link Posted: 1/7/2006 12:46:59 AM EDT
[Last Edit: 1/7/2006 12:54:33 AM EDT by MudBug]
I recently got a good deal on a new Oly stainless carbine barrel. It is marked 5.56, but someone told me that Oly mis-marked these barrels and that it is actually 223. Is this true?


ETA: Changed wording a bit.
Link Posted: 1/7/2006 12:52:40 AM EDT
Randall,

excellent information. Since all those NATO reamers differs a little bit from another, which one of them is "real" NATO reamer,

JGS 5.56 Compass Lake
JGS 5.56 NATO
PTG 5.56 NATO
or
Clymer 5.56NATO?

MN
Link Posted: 1/7/2006 12:59:10 AM EDT
Link Posted: 1/7/2006 1:07:17 AM EDT
[Last Edit: 1/7/2006 1:09:59 AM EDT by Tweak]
Link Posted: 1/7/2006 1:44:10 AM EDT

Originally Posted By Randall_Rausch:
I really don't know.
What I SUSPECT is that the PTG is on the minimum end of NATO specs while the Clymer is on the maximum end of the specs.
I don't know what NATO throat angle is called out.
A lot of this is really up to the reamer makers to look at the specs and then decide how they want to grind the reamer.
It's not uncommon at all to move throat lengths and angles around.
Most people are not aware of the minor nuances of throating, but that's where the accuracy lives and dies in a barrel.



That´s what I thought.

I´d really appreciate, if you could add JGS .223 Wylde reamer specs to your comparison chart. I have the technical drawings for the reamer if you need them.

Thanks,
MN
Link Posted: 1/7/2006 4:21:17 AM EDT

Originally Posted By Tweak:HS gages only tell you the length of the chamber not if it's a 5.56 or .223.

even in barrels that are stamped one or the other the chambers may be the other. the only way to be certain is to cast the chamber and check the throat against the print.


+1
Link Posted: 1/7/2006 9:05:32 PM EDT
So what do you use to cast the chamber?
Link Posted: 1/7/2006 9:27:17 PM EDT

Originally Posted By MudBug:
So what do you use to cast the chamber?



Cerrosafe is probably the best thing to use...
Link Posted: 1/7/2006 9:46:05 PM EDT

Originally Posted By Gunzilla:

Originally Posted By MudBug:
So what do you use to cast the chamber?



Cerrosafe is probably the best thing to use...



Thanks.
Link Posted: 1/7/2006 10:38:44 PM EDT

Originally Posted By MudBug:
I recently got a good deal on a new Oly stainless carbine barrel. It is marked 5.56, but someone told me that Oly mis-marked these barrels and that it is actually 223. Is this true?


ETA: Changed wording a bit.



I've heard that all the barrels are all marked 556 like mine reguardless of lower markings. I've shot nothing but Federal 5.56 through my K3B-MIL4 since day one with out a problem so I have to believe it's 5.56 reguardless of the lower's "Multi caliber" stamp.

Remember 5.56 will fire .223 no problem but not necessarily the other way around.
Link Posted: 1/7/2006 11:27:22 PM EDT

Originally Posted By exccsracer89:

Originally Posted By MudBug:
I recently got a good deal on a new Oly stainless carbine barrel. It is marked 5.56, but someone told me that Oly mis-marked these barrels and that it is actually 223. Is this true?


ETA: Changed wording a bit.



I've heard that all the barrels are all marked 556 like mine reguardless of lower markings. I've shot nothing but Federal 5.56 through my K3B-MIL4 since day one with out a problem so I have to believe it's 5.56 reguardless of the lower's "Multi caliber" stamp.

Remember 5.56 will fire .223 no problem but not necessarily the other way around.




And that's my worry.

This barrel is brand new, but that is all I bought, no lower to be marked "Multi".

The Barrel is marked 5.56, but I'm wondering if it's really a 223 because others have told me that it is. I want to make sure I won't have problems if I shoot XM193 or Q3131 in it.
Link Posted: 1/8/2006 2:37:15 AM EDT
[Last Edit: 1/8/2006 2:42:07 AM EDT by Tweak]
Link Posted: 1/8/2006 2:42:17 AM EDT
Link Posted: 1/8/2006 7:23:33 AM EDT
from seeing the specs of different reamers, and that they are all accross the board , I now think that the main differnce is only in the powder charge/pressure, which I have heard before. I think that the only reason to not shoot 5.56 in a 223 chamberd gun is if it may not handle the increased pressure of the 5.56.. but since the AR IS safe for 5.56 there should be no problem even if no markings confirm it. I could be all wrong, but I have seen no REAL proof yet.
Jim
Link Posted: 1/9/2006 2:26:32 AM EDT
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