50 replies to this topic

[davidbowie]

Maybe you could use a spring to connect the handle and breech, so the handle will pull the breech but not be stopped by it.

Is there really a travel limit on your breech? Sorry to brag, but you should try putting on a breech/clip like the one on the yellow jacket. It has no travel limit, meaning you can move the handle as little as 3" or as far as 2'. Anything farther means the back of the barrel falls out of the barrel sleeve. Also, it's a clip at the start. All the workings are on the inside, so all it takes to add a magazine is gluing on the magazine. I need to make a writeup for it sometime. Maybe I'll do that today.

The SNAPs really are getting better by the minute.

[Carbon]

Yeah, my breech design has a fixed amount of travel because of the seal at the back. It may be a limitation, but the air loss due to the breech is cut down to about nil.

The system I'm working out involves two pegs, one on either end of the pump handle. There's a catchpoint on the barrel. The screws are placed to allow the pump to start moving before it catches the barrel. There's a peg at the other end to pull the barrel back and hold it in place.

I'm not sure if a spring would work, partially because the action is rather firm, and because of the differing travels. But it'd be nice to have a spring on the return trip, so I don't have to work on holding the pump handle back to ensure a seal.

[sniper25]

carbon, here are the links to my snap 4
My Webpage


My Webpage

Edited by sniper25, 23 April 2006 - 11:35 AM.

[davidbowie]

I might not be understanding your breech right, Carbon, but couldn't you extend the travel by using a longer sleeve around the barrel?

[ompa]

Carbon what you're doing now will work wonderfully, I've used it before. Also, you could try running cpvc bars back, and then cutting slots in the cpvc to appropriate lengths so that your pump action engages the bolt at the correct point in time.

~ompa

[Carbon]

I suppose I could extend the travel by extending the barrel or making the 19/32 section longer. Of course, I'm just reusing parts right now, and a longer travel before meant a longer barrel....which is about the last thing I wanted, considering how long SNAPs can get.

Hm, bars would work nicely. My parts bin is totally empty of CPVC right now..I'll have to fix that. I was also trying to make it so I could flip it up and out of the way if I wanted to, just make it a single shot bolt action.

Sniper25: Nice piece of work there! Are the internals the same as the SNAP writeup, or did you use the compact plunger? Just curious as to how you approached it. Also, how are you charging the spring? You have the same slotted PVC in the front, but I can't see a pump handle...

[sniper25]

i did not use the compact plunger on this one. Im using a pump like yours but it is not in the picture because it is being repaired.

Edited by sniper25, 25 April 2006 - 06:59 AM.

[Carbon]

Now this this what I'm talkin' about! Five shot clip, pump and fire. I have had no jams. My only complaint is that it's not exactly easy to pump.


For the breech action, I used a staggered pin system that engages the barrel at different points of travel. And, like ompa was saying, it works beautifully.


The cam system can be flipped up and out of the way if I want to go with single shot. I'm going to adda bolt handle to the breech to facilitate that.


I used Forsaken_Angel's deoderant clip, but with a few modifications. First, I have to say that I dislike gravity feed. You have to treat it quite nicely, and if the gun gets jostled, the darts go sideways. What I needed was a more dependable follower, one that couldn't go sideways. Since the deoderant case already has a hole in the bottom, I just added a rod to my follower. O-rings are at the end of the rod and glued on to keep it from falling out.




Now, when full, the darts keep the follower straight. As the follower decends, the hole and the width of the follower keeps is straight. The weight of the rod and the follower is enough for loading, although I might add a spring if I could find one light enough.


Remember the topic about candy lipstick and their potential as shells? Still haven't done anything about using them as shells, but the curvature of the tubes fits the curves of the deoderant case perfectly. I used a bit of cardboard to narrow up the case just a little.

[Ronster]

Holy crap, man.
That's sooo awsome!

[sniper25]

Carbon im having trouble with my plunger. I think it is the cause of my snap 4's loss in distance.
Here are pictures of my plunger.

fender washers
the one on the top is the same original fender washer, but has been used. You can see that the top washer has been stretched out, could wd-40 be the cause of this
plunger
this is my plunger, is there anything wrong?

Edited by sniper25, 30 April 2006 - 12:57 PM.

[Carbon]

Try replacing your lead endcap with a flat one...I think the problem is the round endcaps you're using. Instead of keeping the washer flat , it's letting too much of the washer stretch down over the edge. Looks like one of them tore from that, as well.

[sniper25]

ok thanks

[ompa]

Carbon, I have a quick question; is the outside curve of a stick of deodorant the same diameter as 1/2" pvc? Because then you could use a magwell similar to Boltsniper's original FAR magwell, the same one I've adopted for my various projects. It would make attachment and whatnot very simple.

~ompa

[Carbon]

Carbon, I have a quick question; is the outside curve of a stick of deodorant the same diameter as 1/2" pvc?

Good catch...I checked it, and it's pretty much the same. Just add a spring retention system and it'd be all set.

Wow...this opens up a bunch of other possibilities. If only gel deoderant wasn't one of the more vile substances to clean up....

Edited by Carbon, 30 April 2006 - 07:36 PM.

[davidbowie]

Yeah...I spent a good half hour trying to get the blob off my floor from cleaning out a deodorant stick.

A FAR style magwell would be pretty cool, but since the cap already snaps on and off, I find that it makes an even better one when dremeled out.

[Ronster]

Does the clip make it hard to aim?

[Carbon]

I haven't done much accuracy testing with it. Hell, I haven't done much firing with it yet. I've been firing from the hip, shotgun style, mostly, so it really hasn't come up yet.

I took it apart tonight and tried to fix the whole difficult-to-cock problem. Turns out it wasn't a weak structural design, it was poor ergonomics. It was hard to cock just because a vertical handle is hard to cock, physically. So I canted the pump handle and barrel off to the side, left the clip and handle vertical.



What has a lot of potential is that the breech can very easily load multiple darts. This gun could be pumped with the trigger held down once, then charged again for an easy shotgun blast. I've actually gotten three darts to fire in this way...but more testing is needed.

Edited by Carbon, 30 April 2006 - 11:23 PM.

[GeneralPrimevil]

I just thought of something. Since you have designed that magazine (I use the term loosely) in such a way, you could very well make Stefans of half the length (and therefore 5/8 of the weight) and hold two darts in tandem within that magazine. That would allow you to do double-feeds with 4 chambered rounds, instead of only two with what is being worked with now.


Or you could just continue with what you are doing and see less range. All your choice...

[Carbon]

I think to effectively chamber more rounds with multiple pumps, I'm going to have to create a way to detatch the pump from the chargerod, and the reattach it to prime and fire. Mainly because if the plunger doesn't catch, it sends a whoose of air down the breech, which has some pretty inconsistent results with already chambered darts. Such a mod isn't too crazy, but it's not something I'm gonna go on this version. I think I may try that ammo style if I turn this into a proper shotgun ,though...

It's pretty much done, save for fine-tuning and cosmetic fixes (removing annoying screws, clumpy glue, filling cracks and painting). Here's a short video of me cracking off four shots (the mag actually holds six).

Four shots (2.7 meg)

Edited by Carbon, 02 May 2006 - 08:37 PM.

[Meaker VI]

I know I've always been intrigued by my cheapish airsoft shotgun (that now lies in peices in a box at home...), and how it can chamber several rounds if pumped more. It works because the pump is attached to the piston/nozzle, which it pushes back, pushing the plunger head back, and locking it onto the trigger. If you continue to pump once the gun is primed, the plunger stays locked while more bbs will chamber. I'm sure something like that would work here too, but probably not for your gun as it is.

[davidbowie]

Actually, now that I think about it, simply going through the cocking motion twice should load two rounds without sending up a puff of air. The plunger would catch on the first time through, and the second pump would be operating only the breech. Am I right?

[Carbon]

I hate it when people understand the mechanics of my guns better than I do.

All kidding aside, you're exactly right, DB...I got hung up on the fact that I got misloads during failed plunger catches, and forgot (somehow) that the breech still moves even after it's charged.

Anyway, that brainfart aside, I tested out the double loading, and it works pretty well...just so long as the barrel is lubed up. I hadn't lubed my barrel in a while, and I was taking two fires to get the darts out. I gave it a spritz of silicone, and I was able to double charge and fire right away. It might be more effective with a shorter barrel, but that's for another time. I'll test ranges and see how far each dart goes.

On another note, the Xerox fuser oil is a fantastic plunger lube. I've lubed up my plungers exactly once, and they're still slippery as all get out.

[Carbon]

I've been going back over some of my older designs and giving a rethink to a few aspects. The old way of actuating the breech on the 4 was a bit rough, mainly because it wasn't very solid.


Also, using tape as a way to affix/anchor anything is awful. It's hard to readjust, and leaves residue everywhere. So, I decided to fix how the breech pins are connected to the barrel. This is the new version.



I'm using hose clamps on the ends to keep the pins from wiggling out of position. I'm using a small strip of innertube under each clamp to keep the barrel from being dented, and to give the clamp something to grab on to.

Previously, I had used tape to space the pins. Bad stuff. This time, o-rings are filling the bill. The nice thing about this method is that you can use pretty much any size. I bought an assortment pack of o-rings a while ago, so I stretched over the ones which were a tight fit.

I still have the functionality of before: it opens and closes the breech, but much more solidly, and I can still flip them up out of the way. The friction of the o-rings keeps them where I rotate them, without residue.

[Flaming Hilt]

Any idea what's next on the list? I heard you were interested in Carrtoon's Tek-9...

[Carbon]

Any idea what's next on the list?

Hopefully, testing this stuff at Spano in a couple of weeks. I'm curious to see if the guided gravity feed will work in a practical fashion.

As far as what's next, I'm just happy to be able to build again after not being able to for a year. Carrtoon's reverse plunger is great...I'm trying to figure out how to...er...SNAP it, build it without his impressive machining skills. But I have some designs kicking around...an attachment for the Big SNAP, something involving Boltsniper's brass breech, wintermute's dual-plunger system, and my long-term design project, the SNAP-A.