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1/4"/1/8" ammo
Posted: Sun Dec 10, 2006 3:56 pm
by 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
Posted: Sun Dec 10, 2006 4:18 pm
by noname
1/8" will be a better fit for BBs and nails, this is by pipe threads right? Not by ID?
Posted: Sun Dec 10, 2006 4:19 pm
by 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
Posted: Sun Dec 10, 2006 8:26 pm
by 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.
Posted: Sun Dec 10, 2006 9:00 pm
by SpudStuff
Well, if you go by the title, you are asking what fits in 1/2 inch pipe.
Posted: Sun Dec 10, 2006 9:10 pm
by 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
Posted: Sun Dec 10, 2006 9:40 pm
by SpudStuff
1/4" pipe isn't 1/4" ID. It is only a nominal size.
Posted: Sun Dec 10, 2006 11:16 pm
by 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.
Posted: Sun Dec 10, 2006 11:28 pm
by 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…
Posted: Mon Dec 11, 2006 2:13 am
by CS
"Plus the larger diameter of pipe would increase the muzzle velocity." ~judgment_arms
Is that so?
Posted: Mon Dec 11, 2006 2:34 pm
by 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
Posted: Mon Dec 11, 2006 3:03 pm
by 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
Posted: Mon Dec 11, 2006 6:39 pm
by 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.