AR15.Com Archives
 Recommendations for a GAS tube
Shermantor-AR15  [Member]
6/25/2011 5:57:58 PM
This one lasted approx 2K rounds, +/- 400
DPMS Carbine tube, there was no damage on the end of the tube where the gas key slides around the tube, and no damage on the Gas Key. So alignment was okay.



I like to run 90-150 rounds between cool downs, could be a 150 round drum dump, or 4-5 30 round mags back to back. I normally let the barrel cool down until I can touch it. Today I might have run it a little harder all 30 round mags today though.. Also I didn't stop shooting because of the gas tube, I just Ran about 300-400 rounds through it today between shooting some 38's and 357s.

Edit to add:
As I said I didn't stop shooting at the range I was just done. I didn't find out it was like this until I got home and was going to clean it. So it didn't fail on me yet, but it will/would have soon.
rv10flyer  [Team Member]
6/25/2011 10:39:42 PM
I wonder if Spike's melonite gas tube would be any better?
Stahlgewehr762  [Member]
6/26/2011 2:01:09 PM
You might want to consider a gas piston upper...
Shermantor-AR15  [Member]
6/26/2011 2:47:38 PM
Originally Posted By Stahlgewehr762:
You might want to consider a gas piston upper...


I have an MGI upper, the older one that is not compatiable with gas piston systems. The new ones are, but I recently dumped $1300 into a Lake City Razorback, with a accesories which doesn't even function well for me in semi, 1-2 rounds and it jams. I am thinking of selling it off and if I so, I probably will get a the newer MGI upper so I can use piston systems on them.

For now though, I just need to find a good gas tube for replacement
ReefRaider  [Team Member]
6/26/2011 9:18:01 PM
Any carbine gas tube will work. Seeing as the gas tube was meant to be the weak link I would think your starting to get some throat erosion then too. Which I believe can lead to bad things the least of which is poor accuracy. Heavy duty gas tubes can be made out of SS brake lines but you will need to know someone with a lathe.
Shermantor-AR15  [Member]
6/26/2011 11:44:54 PM
Where would I be able to see throat erosion? Especially after 2k rounds in a DD hammer cold forged barrel?
ReefRaider  [Team Member]
6/27/2011 5:16:06 PM
Originally Posted By Shermantor-AR15:
Where would I be able to see throat erosion? Especially after 2k rounds in a DD hammer cold forged barrel?


While that cold hammer forged barrel is great for accuracy. I don't think it going to help you to keep from burning out the barrel. It not so much the number of rnds you have put though the barrel its how fast you did put them though it. You can start to shoot out a barrel in 300 rnds. That's 3 beta mag dumps back to back. Even your DD hammer forged barrel was never intended to see that rate of fire.
Will the barrel still fire after that sure, but accuracy will start to go down hill and will go down hill even faster with those types of mag dumps. Once your though the chrome lining its all down hill from there. Let it get bad enough and run the risk of having a projectile get stuck in the barrel. Not catch it and charge and fire another rnd KB.

Personally I limit myself to 1 beta mag dump. I then reload it and fire it again. If I felt the need to dump more ammo than that at one time I would get a belt fed upper.

Shermantor-AR15  [Member]
6/27/2011 6:29:23 PM
as I said the max number of rounds I will do is 150 before cooldowns.

Also I thought the DD barrel has double the chrome lining as a normal one? smiliiar to what is used on a M249 barrel?
ReefRaider  [Team Member]
6/27/2011 7:01:23 PM
All I'm tring to say is that if your melting your gas tube you might be running your upper too hard. Is it fun sure, but it might last longer if you changed uppers once and a while too. It might just be that 150 rnd mag is just too much for that upper.
cosmos556  [Team Member]
6/28/2011 12:24:05 AM
Originally Posted By Shermantor-AR15:
as I said the max number of rounds I will do is 150 before cooldowns.

Also I thought the DD barrel has double the chrome lining as a normal one? smiliiar to what is used on a M249 barrel?


Wasn't it Noveske that had the thicker chrome lining? From Noveske's website:

"Our chrome lined barrels are cold hammer forged and made with the material callouts and manufacturing process for the M249 Machine Gun barrel. The cold hammer forging process work hardens the steel around a rifled mandrel, which creates the lands and grooves. These barrels are chambered in 5.56mm NATO. The barrel is then chrome lined to the spec for a M249 Machine Gun barrel, which is about twice as thick as that of an M4 barrel. The end result is a rifle that can be run hard day after day. Having been part of many excellent training opportunities, I have seen how a barrel may experience serious trauma from high rates of fire and sustained high temperatures. For any high round count, high temp, heavy shooting, I recommend our chrome lined barrel."
jhud  [Team Member]
7/12/2011 11:51:52 PM
Ive had that happen once, with a MGI adjustable gas tube.
After 576 rounds using 30 rd mags.
The adjustmant port thing just kind of blew away.
It was fairly new.




BSOG1  [Team Member]
7/16/2011 2:24:43 AM
id get a piston upper if you want to run it that hard all the time.