1/4"/1/8" ammo

[Kobl]

I'm currently building my parts list for my micro pneumatic cannon on McMaster and I'm wondering which barrel can handle more ammo. I know 1/4 can shoot .177 bb's but what can 1/8" shoot?

-Butt

[noname]

1/8" will be a better fit for BBs and nails, this is by pipe threads right? Not by ID?

[Kobl]

Yep pipe thread, I just did a quick metric conversion and a 1 end threaded stainless steel nipple is pretty much perfect for 6mm airsoft bb's.

Thanks!

-Butt

[noname]

1/8" steel is a good fit but isn't perfect, the BBs shoot out sideways every now and then at about 1 foot sideways for every 5 straight.

[SpudStuff]

Well, if you go by the title, you are asking what fits in 1/2 inch pipe.

[judgment_arms]

If it were me I’d use ¼ inch pipe for the barrel that way you could get .25cal lead balls.
Plus the larger diameter of pipe would increase the muzzle velocity.
You can get .25cal lead balls here:
http://www.pyramydair.com/cgi-bin/show_ ... .25&Type=6

[SpudStuff]

1/4" pipe isn't 1/4" ID. It is only a nominal size.

[noname]

The OD of 1/4" pipe is a tiny bit smaller than 1/2." The OD of 1/8" pipe is 3/8," which makes it a better fit for airsoft BBs, metal BBs, and those .25 caliber lead balls.
I said this already, up there somewhere.

[judgment_arms]

Ok sorry, I keep forgetting the fact that the manufactures like to lie…1/2 pipe being closer to 7/8, Chinese spingers doin’ about half the “box” velocity…

[CS]

"Plus the larger diameter of pipe would increase the muzzle velocity." ~judgment_arms

Is that so?

[judgment_arms]

Yes it’s true I’ll prove it:
Ok gun one, chamber = 1”x5” at 100psi, valve = generic - seat diam.=1” – open time = 2.5 ms, barrel bore = .25”x 5”, projectile weight = 20grains – diameter = .25”
Muzzle velocity = 142fps
Same gun but with a .125 cal barrel and projectile – projectile is same weight.
Muzzle velocity = 42fps

[Kobl]

When you said that the 1/8" inch nipple would sometimes botch the bb's trajectory are you thinking of black steel? I'm using all stainless steel for this and I'm wondering if it has smoother interior walls.

-Butt

[noname]

I'm talking about 1/8" NPT stainless galvanized pipe. It's good and strong, and also easy to mount because of the threads, but sleeve 9/32" brakeline inside of it for accuracy.