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Post by crippledeagle on Apr 11, 2012 18:59:33 GMT -8
]Just built my first .300 AAC Blackout rifle. I own a CMMG in 300 Blackout with a 16" barrel which has given me no problems and has digested everything so far I have tried in it. This rifle has a carbine length gas system in it.
When I started my journey to my first Blackout build I did a ton of research and thinking that since my experience with my CMMG rifle has been so good, I chose to use a carbine length gas system on my new Black Hole barrel that is 11.50" in length. I am using the same spring, buffer, BCG as my CMMG in my build.
I put it together Monday and took it out to shoot it Tuesday after work.
I found it would not cycle using any of the ammo I have here. I have only new factory ammo, no reloads. I started brainstorming as to what was wrong and I seen on some forums those who said it was because my gas hole was too small and suggested a size that would work. I took it apart and found my gas system hole was the recommended size, so where to next?
I was talking with a friend on the phone about it last night and he recommended me sending a message to Robert Silvers at AAC and ask his opinion. He was to the point and said " The 300 Blackout will not cycle the rifle using a carbine gas system if the barrel is less than 16 inches." He explained that the round was designed too put out the maximum amount of gas within a short amount of barrel. He explained that the pressure has to operate the action before the pressure drops when the bullet exits the barrel and it needs a longer barrel to do so when using a carbine system. He said one cannot make a rifle length system work at all with the Blackout. He said that under 16 inches one has to use a pistol length system. We talked about a solution and he stated that if I wanted to save and use my barrel, I would need to get it re-profiled to a pistol gas system and block off the front hole.
I've sent an email to Black Hole asking what the charge would be and if they would do it for me. I have yet to hear from them, but I 'll bet they are discussing it as I have always gotten good service from these folks.
I've talked to a machinist friend of mine who says he can do the work for me if they cannot fit it into their schedule.
What I will do is use a micro gas block so that I can fit it under the hand guards and retain the front gas block with a piece of round stock the same size as a gas tube to retain my front hand guard holder and to block off the hole so no gas escapes.
I hope this helps someone who might be considering building a 300 Blackout using an under 16 inch barrel and using a carbine gas system.
I might have been able to use this when I get to put my suppressor on, but it would not work when shooting it without.
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Post by Brandon Sneed on Apr 11, 2012 19:32:01 GMT -8
]Just built my first .300 AAC Blackout rifle. I own a CMMG in 300 Blackout with a 16" barrel which has given me no problems and has digested everything so far I have tried in it. This rifle has a carbine length gas system in it.
When I started my journey to my first Blackout build I did a ton of research and thinking that since my experience with my CMMG rifle has been so good, I chose to use a carbine length gas system on my new Black Hole barrel that is 11.50" in length. I am using the same spring, buffer, BCG as my CMMG in my build.
I put it together Monday and took it out to shoot it Tuesday after work.
I found it would not cycle using any of the ammo I have here. I have only new factory ammo, no reloads. I started brainstorming as to what was wrong and I seen on some forums those who said it was because my gas hole was too small and suggested a size that would work. I took it apart and found my gas system hole was the recommended size, so where to next?
I was talking with a friend on the phone about it last night and he recommended me sending a message to Robert Silvers at AAC and ask his opinion. He was to the point and said " The 300 Blackout will not cycle the rifle using a carbine gas system if the barrel is less than 16 inches." He explained that the round was designed too put out the maximum amount of gas within a short amount of barrel. He explained that the pressure has to operate the action before the pressure drops when the bullet exits the barrel and it needs a longer barrel to do so when using a carbine system. He said one cannot make a rifle length system work at all with the Blackout. He said that under 16 inches one has to use a pistol length system. We talked about a solution and he stated that if I wanted to save and use my barrel, I would need to get it re-profiled to a pistol gas system and block off the front hole.
I've sent an email to Black Hole asking what the charge would be and if they would do it for me. I have yet to hear from them, but I 'll bet they are discussing it as I have always gotten good service from these folks.
I've talked to a machinist friend of mine who says he can do the work for me if they cannot fit it into their schedule.
What I will do is use a micro gas block so that I can fit it under the hand guards and retain the front gas block with a piece of round stock the same size as a gas tube to retain my front hand guard holder and to block off the hole so no gas escapes.
I hope this helps someone who might be considering building a 300 Blackout using an under 16 inch barrel and using a carbine gas system.
I might have been able to use this when I get to put my suppressor on, but it would not work when shooting it without. As a prostaff, ive been waiting to get my BLk barrel but others have come before it. I've got many customers local that want one too but are waiting for my results (part of tht is a suppressor too but that dilemma is fixed). I wish I had known your length when you said you ordered because I would've helped them give you a pistol gas system instead. If you'd like you can get you a hole drilled at the pistol length with a block profiled out. Then install a lopro block there. Then use some jb weld in the hole of the one at the carbine spot. There won't be enough gas pressure after the pistol length for any thing to cause problems. Of course visit with your gunsmith |
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Post by crippledeagle on Apr 12, 2012 13:15:03 GMT -8
Thank You Brandon
I wish I had done just a little bit more research before I ordered, but I didn't go far enough so basically it was my fault. My hope is that when someone else decides to order a barrel configured like I ordered, the order taker or one tasked with machining the barrel would be able to say "This won't work" and contact the buyer and save another a bit of frustration. We are supposed to learn from our mistakes and the mistakes of others, so here is an example of mine for all to see! 
I am headed out to show my barrel to my machinist friend and show him the reply I got from Robert Silvers of Advanced Armament Company (AAC) about what needs to be done. He said I would have to have it re-profiled and the new hole needed to be drilled 3.075" behind the one in there now.
From: 300Blk
Sent: Tue Apr 10, 2012 10:40 pm
To: Crippled Eagle
Message
Carbine length gas does not work on barrels under 16 inches.
If you are trying to save the barrel, then you can profile the outside to have a pistol length gas port and then weld over the carbine gas port.
3.075 inches closer to the chamber from the carbine location.
Rsilvers
I still have not heard back from the folks at Black Hole, but perhaps my email did not get through. I resent it to 4 different email addresses at Blackhole, so perhaps one will get through. I have far ro many emails hanging out there in space somewhere!
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Post by grgrmp on Apr 18, 2012 21:20:12 GMT -8
Thanks for sharing, I would have chosen a carbine length gas system before reading this thread.
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Post by nonnieselman on Apr 20, 2012 12:50:53 GMT -8
Thats the only reason i didnt buy a BHW 300BO barrel....
If they would do a standard pistol length gas system, id order one today.
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Post by crippledeagle on Apr 20, 2012 14:23:17 GMT -8
I could be totally wrong, but when I ordered my barrel I was asked what gas system I wanted and I chose carbine length for my 11.50 barrel. All of the barrels I have ordered I have always specified how I wanted them whether standard profile, gas system length, barrel length, threaded or non, black, satin or machined. I believe they will do whatever is in their power to supply you with the type and configuration of barrel.
I'd call and talk with them and I'll bet you will find they will make your barrel the way you want it.
They have been nothing but helpful to me even with my problem mentioned in this thread.
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Post by domino on May 26, 2012 8:43:01 GMT -8
Thanks for the heads up. I had no idea as did you on the gas port issue with short barrels. I was thinking about a 14.5 barrel but will stay with a 16".
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Post by vicpapa on Sept 24, 2012 21:35:00 GMT -8
With all due respect, you should have never been sold an 11.5" barrel with a carbine length gas system in that caliber....
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Sept 25, 2012 4:09:55 GMT -8
With all due respect, you should have never been sold an 11.5" barrel with a carbine length gas system in that caliber.... These are custom barrels. Would it not be the customer's responsibility to research what to order? |
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Post by Brandon Sneed on Sept 25, 2012 4:44:37 GMT -8
With all due respect, you should have never been sold an 11.5" barrel with a carbine length gas system in that caliber.... These are custom barrels. Would it not be the customer's responsibility to research what to order? While that may be true this chambering is designed to work on a given platform with certain specs. While the customer has his requests if it is contrary to the ability of the barrel to work, or will affect function from the onset the standards should be adhered to. After working 5 months on my barrel, I found that not only does the port at the carbine have to be opened up too much, but the use of a lighter buffer is required. I'm beginning to think, without an additional barrel to test this theory, the bhw barrels should all be drilled at pistol length to alleviate function issues. (to add: my 16" is car length, and the port was opened to 0.125", the same size as the port on a YHM low profile gas block. The buffer was an H buffer that had one tungsten weight removed, before the rifle would cycle even the weak Remington subsonic 220g loads, factory. The goal of any rifle, regardless of custom or not, is to function with factory ammo. Adding a suppressor, which adds to this niche cartridge, the same goal applies. If the rifle doesn't function with all ammo available then what good is it?) |
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Post by vicpapa on Sept 25, 2012 15:14:59 GMT -8
With all due respect, you should have never been sold an 11.5" barrel with a carbine length gas system in that caliber.... These are custom barrels. Would it not be the customer's responsibility to research what to order? We, as consumers tend to expect manufacturers to be experts in what they sell. The info to avoid this order was out there for everybody involved. As stated by the OP, lesson learned. PS- Would you sell me a 9" 300blk barrel with the gas port 1" from the muzzle because I asked for it? |
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Post by mtbugle on Sept 25, 2012 21:08:11 GMT -8
I just first shot my new 300 blk this weekend and the first bolt I had in it was stove piping. I switched to a new not broken in bolt carrier and it worked fine. I was also only half way to max load from starting load of 4198. (18.5gr iirc) 130 gr bullet. so some carriers may need more wear in than others.
hope this is not hyjacking the thread, but was what I first learned with this new to me cart.
Thanks Don.
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Post by 30harry on Oct 25, 2012 16:01:00 GMT -8
Jumping in a little late but I'm about to order my own blackout barrel. My idea after a lot of research is to order a 16" barrel with the piston gas port and an adjustable low profile gas block. My thinking is that I can shoot just about any load and adjust the gas block for reliable functioning??
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Post by Brandon Sneed on Oct 25, 2012 21:46:57 GMT -8
Jumping in a little late but I'm about to order my own blackout barrel. My idea after a lot of research is to order a 16" barrel with the piston gas port and an adjustable low profile gas block. My thinking is that I can shoot just about any load and adjust the gas block for reliable functioning?? That should be very well reliable if you do intend to use an adj gas block. |
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40rod
Junior Member
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Post by 40rod on Nov 23, 2012 12:46:24 GMT -8
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