pico BBMG - 1mm calibre HPA

[jackssmirkingrevenge]

The smaller BBs will presumably accelerate faster within the vortex block, but what does that actually mean for ROF?

Compare 4.5mm to 1mm at 420 fps, the rash does seem to spread faster with the smaller calibre

[psycix]

Nail art?
Oh yes, you should definitely post this on a nail art forum.

[jackssmirkingrevenge]

Oh yes, you should definitely post this on a nail art forum.

be my guest

*shudder*

Damn I'm glad I was born with male genitalia!

[Brian the brain]

This is your final warning JSR!!

Don't put up such disturbing links..

Better swap it with a nail dart forum link...


Any update yet? Maybe cast it into a nice shell or something?

[jackssmirkingrevenge]

Horrific, isn't it?

No plans to make a shell for it, this is for the sentry and I like having the worky bits showing I still have to make the ball sizer for reliable function, and add the servo that operates the trigger, when I eventually receive the bloody things.

[Insomniac]

Oh yes, you should definitely post this on a nail art forum.

be my guest

*shudder*

Damn I'm glad I was born with male genitalia!

Argh! What is this I don't even...

[jackssmirkingrevenge]

Now that I'm close to getting the turret to work, I'm taking a closer look at making this project reliable. I made a BB sorter as per this concept, see the attached pic (looks a bit like a tiny version of potatoflinger'sairsoft claymore ) - the epoxy is still curing so I don't know if it works yet (or indeed if it works too well and turns into a centrifuge gun, must remember to turn the drill to its lowest setting )

I'm also considering an alternative configuration that has the BB reservoir and valve mounted on the turret base, that then feeds into the barrel through flexible tubing, meaning the servos would have to deal with a lot less load and be a lot more responsive, I might actually be able to use the lighter servos I ordered.

[dewey-1]

centrifuge gun, must remember to turn the drill to its lowest setting

I started to build that gun back when I was a sophmore in high school!
Remember it well. Got about 75% done then other interests came along.(girls)
Never did finish it.

I probably still have the magazine.
They always had neat projects for youngsters to build back then!

[jackssmirkingrevenge]

They always had neat projects for youngsters to build back then!

... sadly seemingly incompatible with most of today's youth, that's why this forum is so refreshing

edit: the sorter worked reasonably well, though I got it to work much faster by sticking a nylon strap in my drill chuck and agitating the BBs from the inside. End result, all the BBs I tried "filtered" through, ergo oversize BBs are not the problem with reliability - back to the drawing board on the design...

[saefroch]

Actually, I found an approximated formula for relationship between muzzle velocity and projectile mass, very approximate because our guns aren't perfect, but muzzle velocity ratio is about equal to the square root of the reciprocal of the mass ratio. Just thought that might be relevant and useful.

[jackssmirkingrevenge]

After a brief hiatus from my workbench, got 1mm BBMG version 2 up and running, with a more carefully built vortex block which turned out to be much more reliable. Testing at ranges beyond point blank proved disappointing though, here it is firing at a tic-tac box with a polystyrene meat tray backing from 6 feet away.

[youtube][/youtube]

You can't really see the impacts, but the camera captured the moment a ricochet shattered the bulb of my floodlight (which as you might remember was left exposed from a 3mm BBMG test ) ah well...

No trouble penetrating the meat tray but there wasn't any one-shot penetration of the box. From a foot away it will happily punch through a cd case, or an alumium beer can. A test against the latter target from six feet away didn't produce a single penetrating hit, just a bunch of dents (and corresponding cloud of stinging ricochets )

The idea going so small was that the projectiles would be powerful enough to cause significant damage from 10-15 feet away, but lose power enough for stray shots to be "safe". I hadn't banked on power dropping off this sharply though, and the fact that the spread of shot is greater at distances disperses the impact which makes the effect on target even worse.

Looks like I've hit a dead end, there's no question of increasing pressure, valve opening is aready much greater than the tiny 1mm outlet , and a longer barrel (currently at 13 inches) will make it too unweildy for sentry gun purposes...

[Hotwired]

What you need is to be firing something with more mass than sand grains if you're going to fire them one at a time down a tube

[jackssmirkingrevenge]

You might have an appropriately small point there... either that or seeing if my vortex block construction will stand up to unregged 3,000 psi air

Or perhaps I should just build an aperture science style testing chamber

[jackssmirkingrevenge]

On second thoughts, a couple of quick half second bursts from across the room are pretty damaging... if only I could get it to shoot reliably!

[POLAND_SPUD]

if only I could get it to shoot reliably

try an inline cloud built from a pipe nipple... mine is quite reliable

I am going to test what effect chamebr volume and valve flow have on feeding...