Gas tube wrapped around the barrel

[TripleDigitRide]

What's the purpose of this?

 

[Dolomite_supafly]

Lengthens the gas system. Basically allows the pressures to drop before reaching the BCG. Almost like having a rifle length gas sytem with the reliability of a carbine length gas system.

[TripleDigitRide]

HOLY ****! $100 for a twisted gas tube?  :stunned: 

[KKing]

Supposedly increases dwell time of your gas system. I've seen people use them on pistol builds to prevent short stroking. They're known as "pigtail" gas tubes

[Oh Shoot]

Supposedly increases dwell time of your gas system. I've seen people use them on pistol builds to prevent short stroking. They're known as "pigtail" gas tubes

 

"Supposedly" is key word, as seems most say it doesn't do anything at all, just a gimmick.

 

A mid length gas system shoots "milder" with longer dwell than a carbine length with same barrel length because of distance of gas port to end of muzzle, not because of the length of the tube, yes?

 

- OS

Edited May 27, 2013 by Oh Shoot

[Dolomite_supafly]

I think it is to prevent overgassing more so than short stroking. Overgassing and short stroking can look similar.

 

The pigtail gives the gasses in the barrel time to drop before the gas hits the BCG. This extra time lets the pressures inside the barrel drop to "normal" levels before the BCG unlocks. If not then the pressures inside the abrrel will be higher than "normal" and those pressures exert more force on the case and the bolt. Those extra pressures inside the barrel as the BCG unlocks cause the BCG to accelerate at a faster rate causing the gun to have malfunctions related to overgassing.

 

By allowing the gasses in the barrel to reduce it reduces the chance of overgassing. Also a properly gassed gun runs cleaner, more reliably and with less felt recoil.

 

Anyone who has shot my 5 pound AR that is properly gassed will attest to how differently a properly gassed gun uns compared to a overgassed gun. And there has been a shift in the industry to overgas guns for "reliability".

[Dolomite_supafly]

BTW, you can do the same thing with an adjustable gas block as you can with a pigtail.

[TripleDigitRide]

BTW, you can do the same thing with an adjustable gas block as you can with a pigtail.

for a whole lot less, I'm sure.

[Dolomite_supafly]

You can get adjustable gas blocks for under $50 shipped.

[KKing]

I think it is to prevent overgassing more so than short stroking. Overgassing and short stroking can look similar.

The pigtail gives the gasses in the barrel time to drop before the gas hits the BCG. This extra time lets the pressures inside the barrel drop to "normal" levels before the BCG unlocks. If not then the pressures inside the abrrel will be higher than "normal" and those pressures exert more force on the case and the bolt. Those extra pressures inside the barrel as the BCG unlocks cause the BCG to accelerate at a faster rate causing the gun to have malfunctions related to overgassing.

By allowing the gasses in the barrel to reduce it reduces the chance of overgassing. Also a properly gassed gun runs cleaner, more reliably and with less felt recoil.

Anyone who has shot my 5 pound AR that is properly gassed will attest to how differently a properly gassed gun uns compared to a overgassed gun. And there has been a shift in the industry to overgas guns for "reliability".

Very good explanation.

[mikegideon]

"Supposedly" is key word, as seems most say it doesn't do anything at all, just a gimmick.

 

A mid length gas system shoots "milder" with longer dwell than a carbine length with same barrel length because of distance of gas port to end of muzzle, not because of the length of the tube, yes?

 

- OS

 

The gas pulse starts when the bullet passes the gas port, and ends when it leaves the muzzle. The gas pressure also drops as the bullet moves down the barrel. For a given barrel length, midlength gas will have less pressure and a shorter pulse.

 

[Romad7]

That's some pretty neat looking software. How well does that work for developing loads?

[Dolomite_supafly]

That's some pretty neat looking software. How well does that work for developing loads?

Works great as long as you don't trust it 100%.

 

I worked with a friend about 7 years ago who had this program. I was working on 7.62x25 Tokarev subsonic loads in an area no one else had went. The numbers were spot on until we started getting numbers below 1,200 fps. There were some recommendations that said the bullet should have been 900-1,000 fps that would get stuck in the barrel. And some recommended loads that were supposed to be well over 1,100 fps were actually well under 800.

 

I would buy it in a heartbeat if it was 1/2 what it costs. But for me $150 is way too much for how often I would use it.

[mikegideon]

I feel like it has paid for itself with me. Since I started out with .458 SOCOM, there were no pressure tested loads. As Dolomite said, you can't trust it completely. It's still real helpful to me.

[Randall53]

Will this get me a 25 on the skeet range?  LOL.....Dayum.....I've been shoot'n and hunt'n for 45 years, but ya'll are so far over my head I feel like a neanderthal spear chucker....from New York City!!  :stare:

Edited May 28, 2013 by Randall53

[mikegideon]

You should hear Dolomite and me on the phone together. We may not hit anything, but we'll have lots of theories why we missed :)

[Romad7]

Thanks guys! That'll go on the list of possibilities to check out.