42 replies to this topic

[Carbon]

I've been wondering for a while if it would be possible for a SNAP to be a practical spring powered ballgun. (Yeah, yeah, I know, ballguns aren't practical. This is science.) Since the most important thing in getting any kind of range with a ballgun is air volume, I went for the big SNAP.

What really piqued my interest in trying whole thing was seeing foam practice golf balls at K-Mart. Roughly the same size as Nerf balls, you can get them a lot cheaper in bulk (50 for $20). If this ends up being practical (HAH!), I don't want to have to keep buying six balls for $4.

The balls have pretty much the same diameter as the OD of 1.25" PVC...which means they shove very nicely into a 1.25" coupler.


It's trivial to make a ballgun barrel...it's the same barrel adapter I use for any other SNAP (.5" PVC -> .5"/1.25" reducer -> 1.25" coupler).


The gun with the barrel.


Intial ranges were, shall we say, modest...so I added a strip of electrical tape to the inside of the barrel to add resistance.


So, ranges. With the current barrel setup, it gets 22-25' pretty consistently. (I tried the barrel on the SNAP-1, and ranges were even worse: about 12'.) It definitely needs the air volume to fire, but I question if either the barrel is currently tight enough or long enough to maximize range. Natrally, I just ran out of electrical tape, so I can't try making the barrel tighter until later.

I'm going to keep experimenting with either the length of the barrel, of some manner of tension points in the barrel, so the ball can be released after a greater buildup of pressure.

Edited by Carbon, 30 May 2016 - 04:56 PM.

[frost vectron]

Haha. Gotta love balls.

I noticed on the original NERF ballshooters (Ballzooka in particular), there was a very tight "lip" on the tip of the barrel that allowed for a lot of pressure build-up (as well as having a great in-line clip system, since the rest of the barrel was "loose").

Maybe if you could add a lip to your barrel of that tightness?

By the way, that snap is freaking huge.

Edited by frost vectron, 14 October 2007 - 06:55 PM.

[Carbon]

Yup, I know exactly what you mean with the "lip". I was considering an o-ring in a groove, but I didn't have any that large....that experiment will come later. I don't know if I could use an inline clip, though....the dead space would be monstrous.

Yeah, this SNAP is a slab. I didn't make the plunger efficiently, though, so it's heavy...the air is a lot slower than it probably could be if I improved air delivery. That might be worthwhile to do, to see if I could improve ball range.

Edited by Carbon, 14 October 2007 - 07:02 PM.

[Nonsense Man]

Carbon if you want one of the lips I can get you one.

[baghead]

Hooray for Ball Guns!

Carbon, I have some extra Ball-barres that I made in the vein of the FingPecan Barrel if you want one, Pm me.

[Carbon]

Some new results with a barrel variant:

I was ruffling through my parts bin, and found a different variety of 1.25" coupler - I believe it's a sanitary coupler. It has an ideal tightening ring right inside:


The length of the coupler is too short to use it directly on a .5"=>1.25" reducing bushing, so I incorporated it the fast and ugly way...

...and just taped it on after the other coupler. After doing some experimenting, I have some interesting results.

1) Currently, the tightening ring is too narrow for the ball to fire once it is pushed past it. However, that's nothing that a little sanding/knife/dremel work can't solve.

2) Range was increased by a few feet (now shooting a consistent 25'), but what was cool is that the power of the shots seems to have increased. The shots would go the distance before, but sort of weakly. They hit the wall with a satisfying *thunk* now. I'd definitely use this in a close quarters game and play the ricochet.

3) There's currently a fair amount of dead space behind the ball. I tried filling it in with a coil of FBR, and the gun shot worse. This bodes well for the possibliity of an inline clip. Time for a parts run!

Edited by Carbon, 30 May 2016 - 04:57 PM.

[frost vectron]

Exciting results, Carbon.

I am thinking that for this type of gun, air flow is much more important than reducing dead-space. The HUGE-ness of your SNAP variant delivers plenty of air volume to accomodate for the deadspace, or something.

[nerfturtle]

If you wanted to get top-notch results with an inline-clip, try this With the clip on top. The problem of different length darts feeding problems would be solved becuase all balls are the same size. This would make it easy to load as well.

[SHADOW HUNTER ALPHA]

As far as I can estimate, the dead space allows for pressure levels behind the ball to increase until peaking and firing the ball out of the coupler. With the FBR, the space is reduced and the pressure cannot build up to as high of a level with the same volume of air delivered to the projectile.

[Carbon]

Yeah...near as I can guess, the dead space allows a larger volume of air to compress directly behind the full surface area of the ball, allowing a greater burst. Although, I did solve a bit of the drop in range when I filled in the dead space before: I had used so much FBR that it was pressing aganist the back of the ball...reducing the surface area the compressed air had to work on (my airflow space was the same ID as .5" PVC). I just tried it again with less FBR, and I had no reduction in range. No increase, either, though. I think the dead space reduction may end up being effective with an inline clip, where the space is much greater. We shall see.

EDIT: Yup, we're both thinking the same thing, SHA...I was typing up mine when you posted.

EDIT #2: I just noticed that my plunger was pretty much dry. A shot of silicone later, and it's now hitting just shy of 30'. Yeah.

Edited by Carbon, 18 October 2007 - 09:51 PM.

[sam]

Looking pretty sweet Carbon. I think you should experiment with a lighter plunger, using CPVC and nylon washers. If it doesn't work out with the balls, you could use Jumbo or Mega darts in an in-line clip, that would be pretty disgusting.

[Carbon]

Looking pretty sweet Carbon. I think you should experiment with a lighter plunger, using CPVC and nylon washers. If it doesn't work out with the balls, you could use Jumbo or Mega darts in an in-line clip, that would be pretty disgusting.

Heh...I was thinking about jumbos or mongos, if I could get my hands on some of the foam....but you're right, an inline of megas would pack serious punch. And if I can find a nylon washer big enough, I can replace the metal one from behind the gasket. Between that and cutting down the catchface, I could save some serious weight.

I'm particularly thinking of using this one for the Belltower rounds at SPANO, as a defense in the tower....firing a ball down the stairs could have a very nice effect.

[WratH]

Is it just me, or is the airflow to the ball choked off by that low diameter stub that you have in there? I'm sure you would get faster airflow if that was either bored out or completely replaced by something larger. Good luck. Ball guns are funny.

[All Star]

VERY awesome job dude! I havent seen many ball-shooting homemades surprisingly!

[Carbon]

Is it just me, or is the airflow to the ball choked off by that low diameter stub that you have in there?

Good point. I'll see if I can use a larger reducing bushing that'll still keep the plunger inside the gun when I make the inline clip.

Ball guns are funny.

Yes, yes they are. The sound of it firing cracks me up.

Edited by Carbon, 30 May 2016 - 04:57 PM.

[sam]

Heh...I was thinking about jumbos or mongos, if I could get my hands on some of the foam....but you're right, an inline of megas would pack serious punch. And if I can find a nylon washer big enough, I can replace the metal one from behind the gasket. Between that and cutting down the catchface, I could save some serious weight.

I'm particularly thinking of using this one for the Belltower rounds at SPANO, as a defense in the tower....firing a ball down the stairs could have a very nice effect.

The hardware store near me just started carrying larger sizes, if you want some just give a a holla'. Here is a McMaster parts number for 1.25" nylon washers: 90295A188.

[crazyguy]

Not to hijack the thread or anything, but since its kind of about making a gun shoot balls i think i should mention that you could make a big blast "blast" a ball about 20'. By using a big toliet roll, e-tape and some cardboard, its like one of those lazy mods(rip off ar, shove in a new barrel and done).

[Carbon]

Huge stuff tonight. And let me tell you, I don't understand ballgun physics. At all.

I stopped at Homie D's tonight and picked up some parts in the hopes of creating an inline clip. I went along with WratH's suggestion, and tried to open up the hole to the barrel as much as possible. 1.5" PVC was too tight for a clip, so that left 2". Since the PC of the big SNAP is also 2", that pretty much means that the clip would be an extension of the PC, right after the initial coupling...interesting.

This actually simplified the barrel somewhat. Home Depot had a 1.25" long coupler that had an inner ring much like the short one I had before....so, used that and did some knifework to shave down one side. I wrapped it in a few turns of e-tape, and shoved it in the end of the 2" PVC. Done.



My Home Depot sells 2.5' segments of the larger PVC sizes. So, on a lark, I used the entire length as an inline clip. Shoved a ball in the end and fired.

The damn thing worked.

Repeated firing wasn't consistent, however, so I cut it down (nevermind that it was a little ungainly). Here it is with the inline clip, as compared to the SNAP-1 with breech barrel:



The entire length after the first coupler is empty space.

Loading is simple: they just push through the muzzle (no disassembly required). By looks, I could fit 8 shots in there.

I loaded it up with five balls (can't find the sixth right now) and did some test firing. 25' every time, with and occasional shot hitting 30' (not counting bounce). No decrease in range. This gun is able to fire using a pluger stroke of about 5", compressing about three times as much linear dead space. I don't get it.

I also picked up a 2" sanitary tee, with the thought of making a vertical gravity clip. However, the inline version works well so far, and isn't really that huge...so it doesn't seem nearly as neccessary as it did this afternoon.

More news as it happens.

Edited by Carbon, 30 May 2016 - 04:58 PM.

[nerfer34]

SWEET!


I think it actually looks cool too.

Hmmm... I wouldn't have imagined the balls woriking with the inline, then again I didn't think darts would work either....

Wicked cool. That would be my primary in a jiff-y.

[nerfturtle]

Haha, Homie D's. That made me giggle. Anyways, awesome work on this, I find it strange that the air has to go around the balls in the clip by only a few millimeters or so and far farther yet it still goes the same range. Does the clip have a spring? Or do you have to piont it down? Great work though, it's good to see balls get some lub <3.

[Carbon]

Yeah, I'm totally puzzled by this. It's like how a bumblebee shouldn't be able to fly, but does anyway.

Does the clip have a spring? Or do you have to piont it down?

Nope, no spring. For right now, I just give it a "point down", and the ball wedges hard enough in the end to fire. I may add a weight like in my SNAP-4. A spring would be nice, if I could find a long enough/weak enough one. I might try one of those coil bind springs, but the larger diameter versions aren't "spring-y" like the smaller ones. Worth a try, though.

[nerfturtle]

Maybe the air has a smaller space to tarvel in (the gap around the balls) so it can only go forward, and it goes faster. I dunno though, I'm no physics expert. As for the spring, you could always take one from a reactor or something like that. I also look on Mcmaster-Carr, but they didn't have anything that fit.

[SHADOW HUNTER ALPHA]

This is my understanding of the answer, although I have only a portion of knowledge on in-line clips:
The in-line clip acts as a plunger tube extension. This means that the pressure in the plunger tube and clip are equal after priming but before firing. Air that is displaced in the 5" plunger stroke is forced forwards and simply raises the pressure enough to pop out the ball. The plunger tube on that gun has a lot of volume, and is bound to get a projectile moving.

Other than that, this thing is a revelation in the use of ballistic balls as ammo.

Edited by SHADOW HUNTER ALPHA, 23 October 2007 - 09:38 PM.

[jwasko]

After I modded my ERTL pump action shotgun, I stuck the stock barrel (which, mind you was an in-line clip/ball barrel) on my titan.

Unfortunately, I had already ripped out the spring and follower that helped seal the balls against the ring at the muzzle.

I didn't measure the range, but it wasn't very good. On the other hand, upon closer examination this past weekend, the barrel/clip wasn't air tight...maybe that had something to do with the horrible ranges.

I'm not sure how much this contributed to the discussion...Just some information for you all to think about, I suppose. Good fortune in your experiments, Carbon.

[SHADOW HUNTER ALPHA]

A seal is created when the ball is either placed in the muzzle or forced there by shaking the gun vertically, though...