Post by Bo/CCPU Founder on Oct 12, 2015 12:53:04 GMT -6
My AR is marked '5.56 NATO' on the barrel, so that means I'm good, right? No, it doesn't.
Patrick Sweeney checked a random sample of ARs during a course he was teaching and found 6 of the 24 were NOT (actually) 5.56 in the internal diameter. He used a gage that owners can get at m-guns.com/tools.php to do so, and they also supply a reamer to correct your rifle if it turns out to be only .223-sized. Mr. Sweeny proceeded to ream the out-of-spec 6 {25%-yikes!] barrels to their (supposed) correct diameter.
So, what could be the consequences of running higher-pressure 5.56 ammo in a gun without a 'true' 5.56 chamber. As you might imagine, a spike in pressure could cause your spiffy AR to blow up in places you don't want, not out the end of the barrel!
More from Sweeney on AR-15s:
This gage tells you if you have a chamber that is 5.56 NATO (or larger), or something shorter/smaller.
The gage looks a lot like a headspace gage but it does not gage headspace. It comes with its own rod which you thread into the tapped hole in the back of the gage. Unload and open your rifle, pull the bolt group, make sure the chamber is clean so there is no false reading, and drop the gage in. If the gage's shoulder "clinks" off on the shoulder of the chamber and the gage drops or pulls free without sticking or resistance, you have a chamber that is 5.56 NATO or larger. If the gage goes in and wants to stick, as in, you let it in and it pulls with a little resistance, or you try and turn it but it does not turn freely, you are short of 5.56 NATO and probably have a .223 chamber. You can color it up with a Sharpie, put it in and spin it (clockwise) to observe where it's contacting the chamber first.
Note that the gage will also stick in a .223 Wylde chamber since the Wylde's freebore is smaller in diameter than the 5.56 NATO's. It's my opinion that the Wylde chamber ought to be OK with 5.56 NATO ammo, but I have not delved into this scientifically. I don't own anything with the Wylde chamber, so I have no first-hand experience with it. The smaller freebore, I suppose, would make it more crud-sensitive.
The newly designed (3/15) handle acts as a case for the gage, preventing loss and damage.
Probing either a .223 SAAMI or .223 Wylde chamber with this gage will not harm the chamber unless you decide to really try by hammering it in. Don't do that.
Price is $50, add $10 for Priority Mail, or $5 for first class.
You can PayPal me the funds using my email, metalmaster@m-guns.com, or send a check made out to Michiguns to:
MG
Box 42
Three Rivers, MI 49093
Now also available in 6.8 SPC with long freebore and throat! Add $20 for 6.8 SPC.
A common problem when firing 5.56 mil-spec ammo in an AR15 with a SAAMI-spec .223 chamber, is that once in a while a spent primer will fall out of a case as it is extracted. Sometimes the primers fall clear and there's no problem, other times they will go under the trigger and get wedged, rendereing the rifle inoperable. I've seen some extreme cases of this where the hammer and trigger were actually hard to get out. I've seen them get wedged between the charging handle and the inside of the receiver, with the bolt out of battery, so that the gun had to have the stock removed so the bolt could be removed to clear the primer. It is not unknown for the primer anvil get stuck on the tubular portion of the carrier key! Popped primers are due in part to the tighter, shorter freebore and shorter, more abrupt throat of the .223 chamber, causing a pressure spike with the hotter, mil- spec ammo. This reamer will address these areas as well as making sure the neck diameter is not too tight or short, without changing headspace. It does not cut the shoulder or anything behind it; it stops off on the shoulder. Of course, whatever rifle you're shooting, you could just look at what's stamped on the barrel-- it might say .223, or it might say 5.56, or it might say nothing. You could call the manufacturer and ask them what chamber you have, but even if you get to talk to somebody who understands the question, they likely don't really know. They may tell you what you want to hear, but truth is, not many AR15 manufacturers make their own barrels. They buy them from someone else, so they don't really, truly know what chamber you have. Some of them will flat decline to discuss it with you.
This reamer is designed as an easy, quick and sure way to know. You just open the upper receiver, remove the bolt group, drop in the reamer with some oil, and slowly turn it in (clockwise only, never reversing it), using a lot of turns and very little pressure. The handle centers itself in the upper receiver. When ithe reamer bottoms out on the chamber's shoulder it will spin freely-- it has stopped cutting and you are done. When you have done this, you know for sure you have a chamber with proper 5.56-plus dimensions in the critical freebore and throat area. Primer popping due to pressure spikes in a short leade will cease, but be advised there can be other factors in popped primers such as hot ammo, hot chambers, and improperly loaded ammo. The new version ($240, shown above) has a redesigned handle that is custom machined from aluminum barstock, so it is quite a bit lighter (handle and reamer weigh less than the original handle alone). It is also shorter to take up less room in your toolbox, and, most importantly, it functions as a storage case for your reamer. When you are finished reaming, simply remove the reamer, reverse it, and insert it into the handle-- your expensive tool is now very well protected and not taking up extra room in your toolbox. There is also a slot in the handle to accept the Allen wrench you need to turn the set screw that retains the reamer. The Allen wrench is retained in the handle so everything you need is right there.
What about chromed-lined chambers? The good news is that in my experience, Colt AR15 chromed barrels have a proper 5.56 chamber. I would consider most others to be suspect. The reamer has been subjected to a secondary heat-treating process, titanium carbo-nitride, which makes it capable of correcting under-spec chromed chambers. Obviously it will do fewer of them, but I have yet to hear of one of my reamers geting dull-- and my personal one has done at least a few dozen chromed chambers. Will removing the chrome be a problem? No. Plenty of AR's don't have chromed bores and chamber and they work fine. I've sectioned some chromed barrels and the chrome doesn't last that long in the throat area anyway. Removing chrome in the chamber won't cause the area to peel like bumper chrome.
Reamer with new lightweight/compact handle that doubles as reamer storage: $240, add $10 for shipping. I always ship Priority Mail which usually gets it there in three days or less.
ORDERING SUGGESTIONS:
I am not set up to take credit cards other than through PayPal. It's easy to set up an account, just go to paypal.com and follow the instructions. I get a lot of orders where the customer doesn't tell me what he's ordering or does not give me an address to ship it to. Sometimes I will receive that info via an Email from a name that is different from the one associated with the payPal order so I don't know what the guy is talking about. Then I might get a phone message that says, "This is So-and-so, just wondering if my stuff shipped yet." The name he gives on the phone is his real name, which is not reflected in his Email address or PayPal order which was sent to Acme, Inc. And no return phone number was left.
Long story short, make sure to state what you're ordering and tell me where to send it..... it'll speed things up for both of us.
If you are ordering more than one tool, there is only one $10 shipping charge.
Patrick Sweeney checked a random sample of ARs during a course he was teaching and found 6 of the 24 were NOT (actually) 5.56 in the internal diameter. He used a gage that owners can get at m-guns.com/tools.php to do so, and they also supply a reamer to correct your rifle if it turns out to be only .223-sized. Mr. Sweeny proceeded to ream the out-of-spec 6 {25%-yikes!] barrels to their (supposed) correct diameter.
So, what could be the consequences of running higher-pressure 5.56 ammo in a gun without a 'true' 5.56 chamber. As you might imagine, a spike in pressure could cause your spiffy AR to blow up in places you don't want, not out the end of the barrel!
More from Sweeney on AR-15s:
.223/5.56? Gage
This gage tells you if you have a chamber that is 5.56 NATO (or larger), or something shorter/smaller.
The gage looks a lot like a headspace gage but it does not gage headspace. It comes with its own rod which you thread into the tapped hole in the back of the gage. Unload and open your rifle, pull the bolt group, make sure the chamber is clean so there is no false reading, and drop the gage in. If the gage's shoulder "clinks" off on the shoulder of the chamber and the gage drops or pulls free without sticking or resistance, you have a chamber that is 5.56 NATO or larger. If the gage goes in and wants to stick, as in, you let it in and it pulls with a little resistance, or you try and turn it but it does not turn freely, you are short of 5.56 NATO and probably have a .223 chamber. You can color it up with a Sharpie, put it in and spin it (clockwise) to observe where it's contacting the chamber first.
Note that the gage will also stick in a .223 Wylde chamber since the Wylde's freebore is smaller in diameter than the 5.56 NATO's. It's my opinion that the Wylde chamber ought to be OK with 5.56 NATO ammo, but I have not delved into this scientifically. I don't own anything with the Wylde chamber, so I have no first-hand experience with it. The smaller freebore, I suppose, would make it more crud-sensitive.
The newly designed (3/15) handle acts as a case for the gage, preventing loss and damage.
Probing either a .223 SAAMI or .223 Wylde chamber with this gage will not harm the chamber unless you decide to really try by hammering it in. Don't do that.
Price is $50, add $10 for Priority Mail, or $5 for first class.
You can PayPal me the funds using my email, metalmaster@m-guns.com, or send a check made out to Michiguns to:
MG
Box 42
Three Rivers, MI 49093
Neck and Throat 5.56 Reamer
Now also available in 6.8 SPC with long freebore and throat! Add $20 for 6.8 SPC.
A common problem when firing 5.56 mil-spec ammo in an AR15 with a SAAMI-spec .223 chamber, is that once in a while a spent primer will fall out of a case as it is extracted. Sometimes the primers fall clear and there's no problem, other times they will go under the trigger and get wedged, rendereing the rifle inoperable. I've seen some extreme cases of this where the hammer and trigger were actually hard to get out. I've seen them get wedged between the charging handle and the inside of the receiver, with the bolt out of battery, so that the gun had to have the stock removed so the bolt could be removed to clear the primer. It is not unknown for the primer anvil get stuck on the tubular portion of the carrier key! Popped primers are due in part to the tighter, shorter freebore and shorter, more abrupt throat of the .223 chamber, causing a pressure spike with the hotter, mil- spec ammo. This reamer will address these areas as well as making sure the neck diameter is not too tight or short, without changing headspace. It does not cut the shoulder or anything behind it; it stops off on the shoulder. Of course, whatever rifle you're shooting, you could just look at what's stamped on the barrel-- it might say .223, or it might say 5.56, or it might say nothing. You could call the manufacturer and ask them what chamber you have, but even if you get to talk to somebody who understands the question, they likely don't really know. They may tell you what you want to hear, but truth is, not many AR15 manufacturers make their own barrels. They buy them from someone else, so they don't really, truly know what chamber you have. Some of them will flat decline to discuss it with you.
This reamer is designed as an easy, quick and sure way to know. You just open the upper receiver, remove the bolt group, drop in the reamer with some oil, and slowly turn it in (clockwise only, never reversing it), using a lot of turns and very little pressure. The handle centers itself in the upper receiver. When ithe reamer bottoms out on the chamber's shoulder it will spin freely-- it has stopped cutting and you are done. When you have done this, you know for sure you have a chamber with proper 5.56-plus dimensions in the critical freebore and throat area. Primer popping due to pressure spikes in a short leade will cease, but be advised there can be other factors in popped primers such as hot ammo, hot chambers, and improperly loaded ammo. The new version ($240, shown above) has a redesigned handle that is custom machined from aluminum barstock, so it is quite a bit lighter (handle and reamer weigh less than the original handle alone). It is also shorter to take up less room in your toolbox, and, most importantly, it functions as a storage case for your reamer. When you are finished reaming, simply remove the reamer, reverse it, and insert it into the handle-- your expensive tool is now very well protected and not taking up extra room in your toolbox. There is also a slot in the handle to accept the Allen wrench you need to turn the set screw that retains the reamer. The Allen wrench is retained in the handle so everything you need is right there.
What about chromed-lined chambers? The good news is that in my experience, Colt AR15 chromed barrels have a proper 5.56 chamber. I would consider most others to be suspect. The reamer has been subjected to a secondary heat-treating process, titanium carbo-nitride, which makes it capable of correcting under-spec chromed chambers. Obviously it will do fewer of them, but I have yet to hear of one of my reamers geting dull-- and my personal one has done at least a few dozen chromed chambers. Will removing the chrome be a problem? No. Plenty of AR's don't have chromed bores and chamber and they work fine. I've sectioned some chromed barrels and the chrome doesn't last that long in the throat area anyway. Removing chrome in the chamber won't cause the area to peel like bumper chrome.
Reamer with new lightweight/compact handle that doubles as reamer storage: $240, add $10 for shipping. I always ship Priority Mail which usually gets it there in three days or less.
ORDERING SUGGESTIONS:
I am not set up to take credit cards other than through PayPal. It's easy to set up an account, just go to paypal.com and follow the instructions. I get a lot of orders where the customer doesn't tell me what he's ordering or does not give me an address to ship it to. Sometimes I will receive that info via an Email from a name that is different from the one associated with the payPal order so I don't know what the guy is talking about. Then I might get a phone message that says, "This is So-and-so, just wondering if my stuff shipped yet." The name he gives on the phone is his real name, which is not reflected in his Email address or PayPal order which was sent to Acme, Inc. And no return phone number was left.
Long story short, make sure to state what you're ordering and tell me where to send it..... it'll speed things up for both of us.
If you are ordering more than one tool, there is only one $10 shipping charge.