11 replies to this topic

[Deaths Avatar]

Well, I have decide that I can't let Ompa, DavidBowie, and Carbon have all the homemade fun these days, so I decided to try my hand at it. Really, this thing is a rip off of everyone else's designs (Ompa's Plunger, Bolt's trigger, Carbon's barrel shape, etc.), but it was still a party to make.

Anyway, I decided to sit down and make a homemade with all the materials I already have (tons of PVC, springs, etc.), and this is what I came up with:


Another goal of this project was to see if I could make a decent blaster using extension springs, rather than compression. Here is a close up of the spring setup (There is an Identical spring at the same distance on the bottom half.):


The trigger setup is very similar to Bolt's from the FAR. I still used the bell-crank setup, but rather than having a swinging trigger, it slides. I did this for two reasons: No force is lost in the up and down component (the force lost with the swinging trigger may be negligible, but whatever); The buckle inhibitors are much easier to fabricate/install because the bar only needs to move back and forth. Here are some nearly in focus pictures:



For now, I have just been muzzle loading stock whistlers (Have to wait for Ace to refill the brass so I can try stefans and maybe some paper darts). To charge the gun, you simply pull back the aluminum rod that is connected to the spring (something of a perverted crossbow). Since I have no brass to nest in the barrel, I won't be able to get ranges for a bit (maybe by Saturday).

There are several obvious issues with this design that will be resolved in the next improvement:
1. It is huge. Really Huge, to the point were I can't hold it against my shoulder and fire comfortably. You may notice that there is a great deal of space between the bottom of the handle and the bottom of the gun. This space was unintentional, but appeared as a side affect of not paying attention to what I was gluing.
2. The springs are a bit much for the trigger. Despite a smooth powerful trigger, the force of the springs is too great on the plunger, pushing the catch against the trigger pin with way too much force, sometimes requiring two hands to fire. I think this can be resolved by removing the bottom spring, it still has a great deal of force with just the one.
3. The charging handle (the metal rod) bends when being pulled back. This is a side affect of the two springs and the gun being too tall, should go away when I fix those issues.

In addition to these changes, I would like to take a stab at some method of improving the rate of fire (probably a clip of sorts).

So there you have it. I figured it was probably time to start posting something that is actually useful. Thanks for reading.

-DA

Edited by Death's Avatar, 16 March 2006 - 07:51 PM.

[Carbon]

That's a cool design! Kudos on stepping outside the box and doing something truly different.

I wonder if your push trigger design is contributing to your hard trigger pull. A swinging trigger gives you a mechanical advantage with a lever, as opposed to just pushing. That being said, the push trigger is really cool, because it's similar to an actual Nerf gun.

I like the shape. You could pretty easily scale down the size in another version with different measurements, and possibly shorter springs. It looks like your springs are at complete rest when the plunger is all the way forward. Perhaps you could use a shorter spring and pre-tension them a bit (either with a stop or a different anchor point), allowing for a shorter gun.

Really interested in hearing what kinds of ranges you can pull with this design....

[Deaths Avatar]

Yeah, the lever did occur to me with the swing trigger, but the push rod would simply buckle (as it did when I built my FAR). Like I said, the sliding trigger allows me to more easily prevent this problem.

The springs actually are pre-tensioned, but just slightly, perhaps a little more would help. Shorter springs also sounds like a great idea...I will have to see what Ace has to offer. Thanks for the reply Carbon.

-DA

Edited by Death's Avatar, 16 March 2006 - 09:02 PM.

[ompa]

Try my trigger. I was talking to bolt, and he said his trigger pull on the FAR was rather large. I've found that even with around 1/2-3/4 cm of a catch pin exposed to catch the plunger, I still have a really really light trigger pull.

Oh and to clarify; I take no credit for the plunger, it's basically Bolt's plunger system with a few modifications.

~ompa

Edited by ompa, 16 March 2006 - 09:28 PM.

[Deaths Avatar]

Well I crammed some brass into the barrel this morning and did some range testing. Here are the results (All in feet) (Don't read this thread though, go read about Bolt's new baby):

71
69
68
45
51

Not sure what happened on those last two , but the first three did decent. All shots were fired flat, at shoulder height, and measured with a rolling tape measure.

Ranges are good, but again the thing is too cumbersome to really use effectively. Continued testing also showed that it is very inconsistent, throwing in the crummy ranges pretty often. Hopefully a more thought out and tighter design will fix that.

Now I am going to go read about Bolt's new weapon and see If I can use any of his ideas from that!

-DA

[Denaeron 12]

Sounds like an easy-to-make homemade. Good job at thinking out of the box with the spring setup.

I like it.

You said it was uncomfortable to hold to your shoulder. Is that because the distance required for the plunger to move back makes the stock long?
If so, then I would suggest making a version of it where the plunger goes back over your shoulder.
Sorry if its confusing, but by that I mean make the area where you rest your shoulder be below the top piece of PVC, and set more towards the front of the gun.
You could then shorten the rod you use to cock the gun.

I can draw something up in paint if you need it, I'm not sure if I explained it very well.

-D

[Deaths Avatar]

If so, then I would suggest making a version of it where the plunger goes back over your shoulder.
Sorry if its confusing, but by that I mean make the area where you rest your shoulder be below the top piece of PVC, and set more towards the front of the gun.
You could then shorten the rod you use to cock the gun.

Yeah, those are basically the two ideas I had. The inside space (the rod length, etc.) was originally only supposed to be as tall as the width of my hand, but various changes in the design and carelessness ruined that.

As far as length goes, I think the next version will probably feature shorter springs, or an over the shoulder setup like you suggested.

-DA

[z80]

I think you would add 5-10 feet on to the range by taking off the whole bar thing, the weight decreases power and the bar adds friction.

[Denaeron 12]

You could use a wooden dowel if the springs aren't too strong, that would be lighter.
Moving it to the side of the gun as in a bolt-action would lower friction (it only touches one of the sides) and make it more convenient to cock in battle.

[Deaths Avatar]

I think you would add 5-10 feet on to the range by taking off the whole bar thing, the weight decreases power and the bar adds friction.

Get rid of the bar thing? The "bar thing" is how you cock the gun and where the springs are attached...

Friction is really no worry, it only scrapes the sides when it is crooked (which only happens because it is so tall and the CPVC bends). A dowel might not be a bad idea, but wood scores low in durability, Not to mention the bar is aluminum, so it is pretty light. A bolt-like rod raises the whole "flying metal" issue that Carbon and Ompa were having earlier, so I think I am going to try and avoid that. Thanks for the suggestions.

-DA

[Denaeron 12]

I hope this gun can really go somewhere; it has a lot of potential.
Best of luck in making an improved version, and keep us posted.

All of these homemades all of a sudden are making me want to finish my own design.

Nice work.
-D

[z80]

I meant have like a small wooden handle with a small bar to attach the spring, so that the bar isnt so big and heavy.