SpudFiles

My latest in a series of attempts to make an acceptable BBMG for my sentry gun project.

In order to cope with the chronic reliability problems, I figured I'd triple my chances for success, by fitting 3 barrels. It solved the reliability problems alright, shoots every time the valve is opened - the problem is that due to the shorter barrel length and increased flow through the barrel for the same input valve, power has suffered, it won't punch through a simple CD... back to the drawing board.

Haha... Now that's an idea. Even though you're wasting alot more air, I'm guessing the super small caliber makes up for it... I might have to make one...

BTW what pressure are you running at?

Yes the stenciled CDs look kinda like boobs...

deathbyDWV wrote:Even though you're wasting alot more air, I'm guessing the super small caliber makes up for it...

The great thing is that the ammunition is so cheap, and with a good magnet and some patience you can recover most of them if firing indoors.

what pressure are you running at?

850 psi, at such a small calibre you can't really afford to run at anything less for decent power.

Very interesting.. Makes sense why power would suck tho.

JDP12 wrote:Makes sense why power would suck tho.

Yep, these 1mm BBs really are on the limit, the shorter barrel(s) was certainly a miscalculation.

Do you intend on retrying it with longer barrels? How about a twin barrel setup?

Insomniac wrote:Do you intend on retrying it with longer barrels? How about a twin barrel setup?

So far I've been working with 30-40cm barrels, on this particular prototype I've halved that to 15cm, with predictable effects.

A twin barrel oerlikon style would certainly be sexy but I think I would rather go for a single long (say 60cm) barrel, possibly with a neodymium magnet "detent" (though I'm not sure if this would interfere with BB agitation and feeding in a positive or negative manner, only one way to find out...), in order to maximise power. It will limit the places I can set up the turret indoors, but the power increase should be worthwhile.

If firing at fast-moving targets, the concentrated firepower advantage of the BBMG is lost so single-round energy is important, and that's what I'd like to go for, even if it's at the expense of compactness and rate of fire.

Hmm, so you're abandoning the multi-barrel concept? How are you going to fix the feeding problems you were having before?

Insomniac wrote:How are you going to fix the feeding problems you were having before?

I guess I'll just have to grin and bear it, I've managed to improve things by flaring out the breech end and "loosening" the bore by spinning a length of 1mm piano wire through the barrel.

jackssmirkingrevenge wrote:
If firing at fast-moving targets, the concentrated firepower advantage of the BBMG is lost so single-round energy is important, and that's what I'd like to go for, even if it's at the expense of compactness and rate of fire.

Single round energy? With a 1mm round? i had to laugh out loud there.

Its just a funny concept, trying to boost muzzle energy of a round that weighs so little.

Any ways, glad to see this project coming along.

Keep up the good works.

jhalek90 wrote:Single round energy? With a 1mm round? i had to laugh out loud there.

Well, it's all relative in this case if I get a single round to punch a clean hole through a CD or a beer can it's what I'd call "powerful"

In this case, due to the fabled "jackhammer effect", at close range a burst from this thing will easily obliterate a CD, but only due to the repeated effect of multiple hits on a small area, which is not what I'm after.

Sandblaster

psycix wrote:Sandblaster

In this case I'll grudgingly have to agree with you

Wow...1mm bbmg..sawed-off version.






Now tell me size doesn't matter....

I think you are also loosing a lot of pressure through the open barrels.
Even though they load a projectile in a split second, a singular bbmg is already a gas guzzler.

You have just multiplied it by three..Wich means gas is gushing out to fast compared to what's coming in...so you lost alot of pressure.
I can imagine a triple barrel like that would load less efficient.

The bernoulli ( sp?) effect these bbmg's are based upon is also lessened.
Gas can flow out " a" hole three times the size of the ammo.

Basically I think you would have the same kind of power you have now, if you took a barrel with 3 times the the cross-section area as the ammo and just fired 1mm bb's out of it.

So multiple barrels make it less efficient... Maybe you should go the other way and use 1/3rd barrels.