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Posted: 2/4/2006 3:01:28 PM EDT
So whats the story on these things? I am looking at building a carbine (16" dissipator type barrel) and want to ensure consistant extraction. I already have plans for the bolt as far as a more powerful extractor spring and rubber donut and insert for it. I heard the pigtail tube aids extraction by delaying the gas pulse. I also heard that by delaying the extraction you are being easier on the bolt. Is this true?

Worth the 90 bucks or not?
Link Posted: 2/4/2006 3:05:55 PM EDT
I don't think it's necessary in a 16" barrel.
Link Posted: 2/5/2006 6:53:45 AM EDT

Originally Posted By Phil_A_Steen:
I don't think it's necessary in a 16" barrel.




I was thinking at some point of building an AR pistol, would that probably be a good time for a pigtail gas tube?
Link Posted: 2/5/2006 8:34:51 AM EDT
Link Posted: 2/5/2006 9:28:00 AM EDT
read the post I made about half way down on this page... then just have the barrel made with a midlength gas system -- I have a midlength dissy, you will love it.
Link Posted: 2/5/2006 9:33:02 AM EDT

Originally Posted By Gunzilla:
read the post I made about half way down on this page... then just have the barrel made with a midlength gas system -- I have a midlength dissy, you will love it.



I'm waiting for the parts to get here for the exact same thing.

Link Posted: 2/5/2006 9:39:17 AM EDT
With say a 7.5 inch barrel the pigtail would allow more gas in the tube to push the bolt back than a regular straight gas tube , I think this was the real purpose of the pigtail
Link Posted: 2/5/2006 4:13:21 PM EDT

Originally Posted By Gunzilla:
read the post I made about half way down on this page... then just have the barrel made with a midlength gas system -- I have a midlength dissy, you will love it.




So would this midlength gas system would have the hole out at the fsb instead of nearer to the chamber?

Who does barrels like this?
Link Posted: 2/5/2006 4:21:30 PM EDT

Originally Posted By Gorto:

Originally Posted By Gunzilla:
read the post I made about half way down on this page... then just have the barrel made with a midlength gas system -- I have a midlength dissy, you will love it.




So would this midlength gas system would have the hole out at the fsb instead of nearer to the chamber?

Who does barrels like this?



midlength gas port is at about 9.5

anyone can make it, parts are COTS now
Link Posted: 2/5/2006 4:29:55 PM EDT
Piggies are NOT worth 90 bucks imo.

when they get hot they contract, so much as 1/4 if they get real hot. Then you will have reliability issues because of gas loss.

Link Posted: 2/5/2006 6:45:02 PM EDT

Originally Posted By Gorto:

Originally Posted By Gunzilla:
read the post I made about half way down on this page... then just have the barrel made with a midlength gas system -- I have a midlength dissy, you will love it.




So would this midlength gas system would have the hole out at the fsb instead of nearer to the chamber?

Who does barrels like this?



CMMG Inc. has them.

Link Posted: 2/6/2006 10:44:18 PM EDT
[Last Edit: 2/6/2006 10:44:40 PM EDT by AR15barrels]
Link Posted: 2/7/2006 5:23:05 PM EDT

Originally Posted By Gunzilla:

Originally Posted By Gorto:

Originally Posted By Gunzilla:
read the post I made about half way down on this page... then just have the barrel made with a midlength gas system -- I have a midlength dissy, you will love it.




So would this midlength gas system would have the hole out at the fsb instead of nearer to the chamber?

Who does barrels like this?



midlength gas port is at about 9.5

anyone can make it, parts are COTS now





Dumb question, does a BM Dissipator type barrel have the gas port at 9.5 or is it closeer to the chamber?
Link Posted: 2/7/2006 5:26:18 PM EDT

Originally Posted By AR15barrels:
Read How it Works
Then you will know a little about what it takes to make it run reliably.
Note the chart with port pressures of the different length gas systems.



That makes for some interesting reading, thanks for posting. Mid length is the way to go.
Link Posted: 2/7/2006 5:29:29 PM EDT

Originally Posted By ian187:

Originally Posted By Gorto:

Originally Posted By Gunzilla:
read the post I made about half way down on this page... then just have the barrel made with a midlength gas system -- I have a midlength dissy, you will love it.




So would this midlength gas system would have the hole out at the fsb instead of nearer to the chamber?

Who does barrels like this?



CMMG Inc. has them.




I see the barrel has an M4 barrel extension, can you use this barrel in a non M4 cut upper?
Link Posted: 2/7/2006 5:29:47 PM EDT

Originally Posted By Gorto:

Originally Posted By Gunzilla:

Originally Posted By Gorto:

Originally Posted By Gunzilla:
read the post I made about half way down on this page... then just have the barrel made with a midlength gas system -- I have a midlength dissy, you will love it.




So would this midlength gas system would have the hole out at the fsb instead of nearer to the chamber?

Who does barrels like this?



midlength gas port is at about 9.5

anyone can make it, parts are COTS now





Dumb question, does a BM Dissipator type barrel have the gas port at 9.5 or is it closeer to the chamber?



Most of the "dissy" systems have the gas port at 7.5" (carbine position)... that was much more common when the dissy idea first came out -- But there are people that do have barrels with the midlength dissy system: CMMG for one, I am sure ADCO can hook you up, Randall at AR15BARRELS... it is far worth the money to go with the midlength system.
Link Posted: 2/7/2006 5:44:31 PM EDT
I recently built a 10.5" SBR using a pigtail to "help" with gas issues.
Darned thing kept short stoking. I installed the normal carbine length tube and it runs like a scalded dog.

Don't buy one![:)
Link Posted: 2/10/2006 3:01:42 PM EDT
I think I'm going with the CMMG barrel. I think I will send off my upper to KKF to have him properly cut in the feed M4 ramps . Thanks for all of the feedback.
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