Best Material for steel BB barrel.

[dougroundup]

I have Googled and been looking all over different forums trying to locate a diy solution for smooth bore BB gun barrels.
 I have heard brake line mentioned a few times but it seems rather subpar.
The most avail and readily afforded material I can locate so far is 1/4" stainless steel DOM tubing with a i.d. of .180 
This seems a bit loosely as far as tolerance goes.
Surely there is something out there that is the bees knees that those in the know, knows?
What is the cats meow for BB gun barrels?

[bantam5s]

What exactly is the issue you're trying to solve ?

[Frank in Fairfield]

Steel!

[dougroundup]

What exactly is the issue you're trying to solve ?

I have a bunch of umarex steel storm power plants that I am wanting to tinker with and build stuff from... I want to install a longer shrouded barrel to make these into rifles and hope to increase the velocity with maybe tighter tolerance and utilize the full volume of air that is capable of blowing down a longer barrel.
I want to build/fabricate my own bb guns,  with emphasis on high velocity/high rate of fire/high capacity, full auto maximum shred bb gun destructive devices run on HPA.

[Back_Roads]

It will be ruffled but a great barrel , get a Daisy 880 barrel from Mother Ship Daisy

[bantam5s]

What exactly is the issue you're trying to solve ?

I have a bunch of umarex steel storm power plants that I am wanting to tinker with and build stuff from... I want to install a longer shrouded barrel to make these into rifles and hope to increase the velocity with maybe tighter tolerance and utilize the full volume of air that is capable of blowing down a longer barrel.
I want to build/fabricate my own bb guns,  with emphasis on high velocity/high rate of fire/high capacity, full auto maximum shred bb gun destructive devices run on HPA.

There's a guy on  called blackBarrelCustoms who sells carbon fiber barrels for the daisy bb guns, apparently they have tighter tolerances.
I don't know if those would work out for a high velocity full auto gun though.

[dougroundup]

I am going to have to check out black barrel customs, that sounds like an interesting application of carbon fiber.  The Daisy 880 barrel seems to be a fairly popular option. I wonder if these can be sourced straight thru Daisy or if this is a solution that is only at the sacrifice of a donor rifle?
For the time being I sourced thru Grainger some seamless 316 stainless steel 1/4"O.D. x .035"W.T. x nominal .180"i.d. x 6 Ft length for $18.00
Not too expensive for tinkering around.
Compared to several of the inexpensive CO2 BB pistols that I have noted, it appears that .180" barrel diameter is not excessive a tolerance for smoothbore BB-Gun.
The 316 alloy appears to be hard enough to take a decent amount of beating from the constant peening of steel BB's being pushed down the barrel.
In fact my initial impression is that this stuff is indeed a hard enough material to dull out my baby tooling on my micro lathe. It was difficult to part, groove and crown. even deburring took some patience. I am sure that it will be much easier with my 12 x 36 full sized lathe and larger tooling!
I probably start a new post in one of the project or machinist gates.
But so far just a quick and dirty down experiment, I replaced the six inch barrel from a different CO2 blowback gun (KWC UZI) with a 24" section of this Stainless Steel. I shot four or five rounds from a brand new C02 cartridge at room temp. with the stock barrel into the interior wall of my shop office. At a distance of 25ft the BBs stuck into the wall with about half the diameter of the BB still above the surface of the wall. Replacing with 24" barrel using the same cartridge and the BBs fully imbedded level with the wall surface.  Brand new cartridge at room temp and the next group the majority embedded beyond the depth of view of the copper BB (or perhaps bounced out?) . 
I will perform a better more controlled test once I figure out optimum lengths vs volume of available air for each shot. I will then utilize HPA instead of C02 and run the shots thru the chrony.
I doubt there is alot I can do to make for more power with the Gas Blow Back design of the Steel Storm, but it is what I have to tinker with,,,,,
I suppose anything that I can do to clean it up and reduce friction in the action and make sure no air blows by the piston and air seals tight everywhere along the air circuit. I am going to have it tethered on HPA So I am not worried about complete air efficiency. I might be able to open the valving a smidge without sacrificing blow back timing. 
At the very least it seems that increasing barrel length will indeed give the easiest achievable gain. My primary goal is fairly fantastic ambition and that is to fabricate some sort of automatic chamber feed of bb's from bulk source. The BBs need to be somehow pushed or forced from a bulk reservoir and thru a tube into the chamber. Perhaps a mechanical lead screw? Wracking my brains out in this one! I saw an old you tube of a guy with a rotory hopper fed steel storm. Another thing I noted is that the airsoft guys are doing some sort of bulk fed power magazine feed thing and have even retrofitted these hicap mags to tethered Blow back pistols thru the conveyance of a tubular feed from the bulk source.

Getting a bit off topic,,,, but the point is that for a quick and dirty easy to source barrel,,,,,, there is indeed .180" I.D. seamless stainless steel tubing avail in 6 ft lengths. it might not be the easiest to cut and work with but should be more than resilient enough for steel BBs. Especially if you have true .177 cal BBs and not the .172 ish Crossman coppercoat walmart BBs I am using now. Lengths over 10" , you likely would wish to shroud and bush the barrel to keep it rigid and straight. For novelty BB Gun use, I think that this would make a great basis for barrels and could even fabricate a real nice custom shot tube for your old Daisy Red Rider style piston guns.