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Posted: 11/21/2012 2:14:30 AM EDT
I have not. It seems like it would be an easy mistake to make and not notice until it booms.
Link Posted: 11/21/2012 2:38:53 AM EDT
[#1]
a 556 will not chamber in a 300 blk rifle.
Link Posted: 11/21/2012 2:41:05 AM EDT
[#2]
Quoted:
a 556 will not chamber in a 300 blk rifle.


how do you figure this?
Link Posted: 11/21/2012 2:46:30 AM EDT
[#3]
Link Posted: 11/21/2012 3:32:21 AM EDT
[#4]
NO.....
but I have seen .300 Winchester Mag fired in a .300 Weatherby chamber.I'll see if I can find a photo.

here it is:


center is .300 Weatherby,right is .300 Win Mag.
Link Posted: 11/21/2012 4:05:25 AM EDT
[#5]
Quoted:
Quoted:
a 556 will not chamber in a 300 blk rifle.


how do you figure this?


The shoulder on the .300 is quite a bit further back than on 5.56.

ETA: if you were able to get it to chamber for some reason, it wouldn't do much.  Obviously the gun would t cycle due to no gas pressure.  The case would be blown out.
Link Posted: 11/21/2012 4:16:38 AM EDT
[#6]


That's a 300 chambered in a 5.56.
Link Posted: 11/21/2012 4:34:27 AM EDT
[#7]
Seen plenty of 9mm brass that managed to get fired in a .40



Link Posted: 11/21/2012 9:01:56 AM EDT
[#8]
5.56 and .223 will not  chamber in a .300 blackout, the .223 case is too large of a diameter at the same point of the shoulder of the .300 blackout case.  It will partially seat but the bolt will be out of battery by a noticeable amount.
Link Posted: 11/21/2012 9:36:44 AM EDT
[#9]
It would be very noticeable if you try to chamber a 223 in a 300 Blk Out.

I just ran a 223 dummy through a 300 Blk sizing die with the decapper removed and here is what it looks like.

Left normal 223, center a 223 forced into a 300 blk sizing die, right a 300 Blk round.

Link Posted: 11/21/2012 2:40:30 PM EDT
[#10]
Great picture!  Thanks for taking the time to do this because it says it all.

If someone looks at that and still thinks you can load a 5.56 in a 300 BLK chamber under ANY circumstances, then you will never convince them otherwise.
Link Posted: 11/21/2012 2:49:55 PM EDT
[#11]



Quoted:



Quoted:

a 556 will not chamber in a 300 blk rifle.




how do you figure this?


because this question was asked before. I did not think it would

but went ahead and tried and the bolt will not come close to closing.





 
Link Posted: 11/21/2012 2:52:31 PM EDT
[#12]



Quoted:


Great picture!  Thanks for taking the time to do this because it says it all.



If someone looks at that and still thinks you can load a 5.56 in a 300 BLK chamber under ANY circumstances, then you will never convince them otherwise.


Maybe you might be able to open the upper and beat the BC carrier with a hammer

and possibly stuff the 556 in the 300 chamber



 
Link Posted: 11/21/2012 10:57:53 PM EDT
[#13]
Cool. Thanks for all the responses and the work with the dummy round.

I guess I hadn't thought it all the way through before asking.
Link Posted: 11/22/2012 12:34:17 AM EDT
[#14]
Quoted:
It would be very noticeable if you try to chamber a 223 in a 300 Blk Out.

I just ran a 223 dummy through a 300 Blk sizing die with the decapper removed and here is what it looks like.

Left normal 223, center a 223 forced into a 300 blk sizing die, right a 300 Blk round.

http://i245.photobucket.com/albums/gg76/gi57/300AAC/6805CE2F-C4CF-4F84-B557-31DC1C9A4E5E-14662-00000E19B77C3788.jpg


Nice .223 Blackout.  Get it SAAMI approved and it will be all the rage!

I hope I never accidently fire a 300BLK in any of my .223's though.
Link Posted: 11/22/2012 2:31:37 AM EDT
[#15]
Quoted:

Quoted:
Quoted:
a 556 will not chamber in a 300 blk rifle.


how do you figure this?

because this question was asked before. I did not think it would
but went ahead and tried and the bolt will not come close to closing.

 


nice. well I just learned something as well!
Link Posted: 11/22/2012 8:36:01 AM EDT
[#16]



Quoted:



Quoted:

It would be very noticeable if you try to chamber a 223 in a 300 Blk Out.



I just ran a 223 dummy through a 300 Blk sizing die with the decapper removed and here is what it looks like.



Left normal 223, center a 223 forced into a 300 blk sizing die, right a 300 Blk round.



http://i245.photobucket.com/albums/gg76/gi57/300AAC/6805CE2F-C4CF-4F84-B557-31DC1C9A4E5E-14662-00000E19B77C3788.jpg




Nice .223 Blackout.  Get it SAAMI approved and it will be all the rage!



I hope I never accidently fire a 300BLK in any of my .223's though.


That's impossible... hell I'd like to see someone try to do it intentionally!



The 308 bullet is obviously quite a bit bigger than 223/556 and it never even comes close to going into battery.





 
Link Posted: 11/22/2012 10:13:31 AM EDT
[#17]
Quoted:

Quoted:
Quoted:
It would be very noticeable if you try to chamber a 223 in a 300 Blk Out.

I just ran a 223 dummy through a 300 Blk sizing die with the decapper removed and here is what it looks like.

Left normal 223, center a 223 forced into a 300 blk sizing die, right a 300 Blk round.

http://i245.photobucket.com/albums/gg76/gi57/300AAC/6805CE2F-C4CF-4F84-B557-31DC1C9A4E5E-14662-00000E19B77C3788.jpg


Nice .223 Blackout.  Get it SAAMI approved and it will be all the rage!

I hope I never accidently fire a 300BLK in any of my .223's though.

That's impossible... hell I'd like to see someone try to do it intentionally!

The 308 bullet is obviously quite a bit bigger than 223/556 and it never even comes close to going into battery.

 


It's happened more than once, just look around a little...
Link Posted: 11/22/2012 10:37:03 AM EDT
[#18]



Quoted:



Quoted:




Quoted:


Quoted:

It would be very noticeable if you try to chamber a 223 in a 300 Blk Out.



I just ran a 223 dummy through a 300 Blk sizing die with the decapper removed and here is what it looks like.



Left normal 223, center a 223 forced into a 300 blk sizing die, right a 300 Blk round.



http://i245.photobucket.com/albums/gg76/gi57/300AAC/6805CE2F-C4CF-4F84-B557-31DC1C9A4E5E-14662-00000E19B77C3788.jpg




Nice .223 Blackout.  Get it SAAMI approved and it will be all the rage!



I hope I never accidently fire a 300BLK in any of my .223's though.


That's impossible... hell I'd like to see someone try to do it intentionally!



The 308 bullet is obviously quite a bit bigger than 223/556 and it never even comes close to going into battery.



 




It's happened more than once, just look around a little...



So a perfectly functioning AR can now light up 300 blk round when over an inch OOB?  I was under the impression that the bolt needed to be locked into the extension before the firing pin could hit the primer.   I looked and saw a pic of a blowed up upper supposedly from this... but until someone can explain the OOB deal to me, I'm calling BS.



 
Link Posted: 11/22/2012 10:56:15 AM EDT
[#19]
This has been gone through a LOT in the past.  The .223/5.56 will NOT fully seat in a 300 BLK chamber, so the bolt will NOT go into battery.  The firing pin on an AR will NOT strike the primer unless the bolt is fully rotated (in battery).  Here's a photo of a 5.56 round in a 300 BLK gauge.  Notice how much sticks out the back.  Just to further demonstrate I made up an inert 5.56 round with clay in the primer pocket.  I then tried to chamber it in my 300 BLK.  The bolt would NOT go into battery.  The hammer did fall, but didn't come close to the firing pin.



Link Posted: 11/22/2012 11:14:20 AM EDT
[#20]
OK, I just tried it the other way and a 300 BLK round WILL chamber in a 5.56 gun and the bolt does go fully into battery.  I can only assume that it would fire, but I wasn't stupid enough to have a firing pin in the gun for the test.  I don't have a 5.56 case gauge.  I guess I'll have to make up a dummy 300 BLK round with clay to get some pics.
Link Posted: 11/22/2012 11:27:10 AM EDT
[#21]
Quoted:

Quoted:
Quoted:

Quoted:
Quoted:
It would be very noticeable if you try to chamber a 223 in a 300 Blk Out.

I just ran a 223 dummy through a 300 Blk sizing die with the decapper removed and here is what it looks like.

Left normal 223, center a 223 forced into a 300 blk sizing die, right a 300 Blk round.

http://i245.photobucket.com/albums/gg76/gi57/300AAC/6805CE2F-C4CF-4F84-B557-31DC1C9A4E5E-14662-00000E19B77C3788.jpg


Nice .223 Blackout.  Get it SAAMI approved and it will be all the rage!

I hope I never accidently fire a 300BLK in any of my .223's though.

That's impossible... hell I'd like to see someone try to do it intentionally!

The 308 bullet is obviously quite a bit bigger than 223/556 and it never even comes close to going into battery.

 


It's happened more than once, just look around a little...

So a perfectly functioning AR can now light up 300 blk round when over an inch OOB?  I was under the impression that the bolt needed to be locked into the extension before the firing pin could hit the primer.   I looked and saw a pic of a blowed up upper supposedly from this... but until someone can explain the OOB deal to me, I'm calling BS.
 


Some ammo will fully chamber some won't. There is more than one blown-up rifle out there from it.

Link Posted: 11/22/2012 11:33:51 AM EDT
[#22]







Quoted:
Quoted:
Quoted:






Quoted:
Quoted:






Quoted:



It would be very noticeable if you try to chamber a 223 in a 300 Blk Out.
I just ran a 223 dummy through a 300 Blk sizing die with the decapper removed and here is what it looks like.
Left normal 223, center a 223 forced into a 300 blk sizing die, right a 300 Blk round.
http://i245.photobucket.com/albums/gg76/gi57/300AAC/6805CE2F-C4CF-4F84-B557-31DC1C9A4E5E-14662-00000E19B77C3788.jpg

Nice .223 Blackout.  Get it SAAMI approved and it will be all the rage!







I hope I never accidently fire a 300BLK in any of my .223's though.




That's impossible... hell I'd like to see someone try to do it intentionally!
The 308 bullet is obviously quite a bit bigger than 223/556 and it never even comes close to going into battery.
 

It's happened more than once, just look around a little...







So a perfectly functioning AR can now light up 300 blk round when over an inch OOB?  I was under the impression that the bolt needed to be locked into the extension before the firing pin could hit the primer.   I looked and saw a pic of a blowed up upper supposedly from this... but until someone can explain the OOB deal to me, I'm calling BS.



 

Some ammo will fully chamber some won't. There is more than one blown-up rifle out there from it.
sorry Dude...  not under normal conditions, as the firing pin would have to be stuck and protruding from the bolt in order for something like that to happen.  and even then it will never fully chamber.  Now your being silly.

Thanks for the clarification JC10311!
 
Link Posted: 11/22/2012 11:57:56 AM EDT
[#23]
You misunderstood, I never said it would fire OOB. It will fire; however, if the round fully chambers and you pull the trigger. This is the only thing I've seen in the cases posted on the net. JC1031 just said that his round chambered, some others will not.

BTW: I've had a OOB kaboom, and while I'm glad I was wearing eye pro, it looked nothing like any of these rifles. The pressure in a OOB kaboom is much lower, in my experience and research after the fact, it is not enough to peel an upper back like a banana.

Linky
Link Posted: 11/22/2012 12:11:45 PM EDT
[#24]
One thing certainly has been demonstrated in this thread.



Some of us have no real lives.



Happy Thanksgiving.  
Link Posted: 11/22/2012 12:15:09 PM EDT
[#25]



Quoted:


You misunderstood, I never said it would fire OOB. It will fire; however, if the round fully chambers and you pull the trigger. This is the only thing I've seen in the cases posted on the net. JC1031 just said that his round chambered, some others will not.



BTW: I've had a OOB kaboom, and while I'm glad I was wearing eye pro, it looked nothing like any of these rifles. The pressure in a OOB kaboom is much lower, in my experience and research after the fact, it is not enough to peel an upper back like a banana.



Linky


It will fire; however, if the round fully chambers and you pull the trigger.  



You are correct Sir.  However, if you can get a 308 cal bullet to fully chamber in a 5.56 barrel, you are a fucking magician of Houdini proportions.  Seriously.



 
Link Posted: 11/22/2012 12:19:49 PM EDT
[#26]



Quoted:


One thing certainly has been demonstrated in this thread.
Some of us have no real lives.
Happy Thanksgiving.  


I'm having to spend it alone... but thanks for not being a dick about it



Besides this is a fun way to work on my post count.



HAPPY THANKSGIVING EVERYONE!









 
Link Posted: 11/22/2012 12:25:15 PM EDT
[#27]
Quoted:
One thing certainly has been demonstrated in this thread.



Some of us have no real lives.



Happy Thanksgiving.  


Four women in my house and I've already cleaned the garage and all my guns... I guess I should've volunteered for duty.

Link Posted: 11/22/2012 1:14:42 PM EDT
[#28]
Here's a little more fuel for the fire:

Link Posted: 11/22/2012 1:22:39 PM EDT
[#29]
Quoted:
NO.....
but I have seen .300 Winchester Mag fired in a .300 Weatherby chamber.I'll see if I can find a photo.

here it is:
http://i85.photobucket.com/albums/k60/DanaHillen/WMagcase004.jpg

center is .300 Weatherby,right is .300 Win Mag.
http://i85.photobucket.com/albums/k60/DanaHillen/WMagcase005.jpg


just out of curiousity, how did that work out?  my g/f has a .300 weatherby (and .243) and her dad has a TON of 300 win mag ammo he doesnt use.  I am sure accuracy will suffer some, but in a STHF situation, would putting 300 wm in the weatherby  still work?
Link Posted: 11/22/2012 1:33:14 PM EDT
[#30]
Quoted:

Quoted:
You misunderstood, I never said it would fire OOB. It will fire; however, if the round fully chambers and you pull the trigger. This is the only thing I've seen in the cases posted on the net. JC1031 just said that his round chambered, some others will not.

BTW: I've had a OOB kaboom, and while I'm glad I was wearing eye pro, it looked nothing like any of these rifles. The pressure in a OOB kaboom is much lower, in my experience and research after the fact, it is not enough to peel an upper back like a banana.

Linky

It will fire; however, if the round fully chambers and you pull the trigger.  

You are correct Sir.  However, if you can get a 308 cal bullet to fully chamber in a 5.56 barrel, you are a fucking magician of Houdini proportions.  Seriously.
 


Guess what.... The .308 bullet doesn't go into the 5.56 barrel. There is setback if your crimp is not strong enough and the .308 bullet will stay in the chamber.
Link Posted: 11/22/2012 1:48:17 PM EDT
[#31]



Quoted:



Quoted:




Quoted:

You misunderstood, I never said it would fire OOB. It will fire; however, if the round fully chambers and you pull the trigger. This is the only thing I've seen in the cases posted on the net. JC1031 just said that his round chambered, some others will not.



BTW: I've had a OOB kaboom, and while I'm glad I was wearing eye pro, it looked nothing like any of these rifles. The pressure in a OOB kaboom is much lower, in my experience and research after the fact, it is not enough to peel an upper back like a banana.



Linky


It will fire; however, if the round fully chambers and you pull the trigger.  



You are correct Sir.  However, if you can get a 308 cal bullet to fully chamber in a 5.56 barrel, you are a fucking magician of Houdini proportions.  Seriously.

 




Guess what.... The .308 bullet doesn't go into the 5.56 barrel. There is setback if your crimp is not strong enough and the .308 bullet will stay in the chamber.



 


Yes, that is something I hadn't considered.  I have AR's in both 5.56 and 300 and have attempted to chamber one round in the other on both, and it seemed impossible.



Although I'm sure no-one would want zero crimp on the projectile and assuming that there is enough available volume in the case to set it back enough to go completely into battery it could indeed be catastrophic.  I've learned something important today, as I'm just about to start reloading so I'll be looking at crimp dies now!



My apologies to lwrkeysfisher, if I came across as a dick it was probably accurate! My bad



Again, happy thanksgiving everyone!



Link Posted: 11/22/2012 2:08:17 PM EDT
[#32]
Quoted:

Quoted:
Quoted:

Quoted:
You misunderstood, I never said it would fire OOB. It will fire; however, if the round fully chambers and you pull the trigger. This is the only thing I've seen in the cases posted on the net. JC1031 just said that his round chambered, some others will not.

BTW: I've had a OOB kaboom, and while I'm glad I was wearing eye pro, it looked nothing like any of these rifles. The pressure in a OOB kaboom is much lower, in my experience and research after the fact, it is not enough to peel an upper back like a banana.

Linky

It will fire; however, if the round fully chambers and you pull the trigger.  

You are correct Sir.  However, if you can get a 308 cal bullet to fully chamber in a 5.56 barrel, you are a fucking magician of Houdini proportions.  Seriously.
 


Guess what.... The .308 bullet doesn't go into the 5.56 barrel. There is setback if your crimp is not strong enough and the .308 bullet will stay in the chamber.
 

Yes, that is something I hadn't considered.  I have AR's in both 5.56 and 300 and have attempted to chamber one round in the other on both, and it seemed impossible.

Although I'm sure no-one would want zero crimp on the projectile and assuming that there is enough available volume in the case to set it back enough to go completely into battery it could indeed be catastrophic.  I've learned something important today, as I'm just about to start reloading so I'll be looking at crimp dies now!

My apologies to lwrkeysfisher, if I came across as a dick it was probably accurate! My bad

Again, happy thanksgiving everyone!



No worries, if we just accepted what others said without applying our own knowledge and experience we would never get anywhere. Enjoy the rest of your thanksgiving.
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