Page 1 of 3

The Gutmenduff Mk1.3

Posted: Mon Jan 05, 2009 6:23 pm
by VH_man
First of all the name. Gutmenduff is what it sounds like when you say the abbreviation "G.T.M.N.D.F.F" or Gun That Makes Nerf Darts Fly Fast.

Of course, I wouldn't Post just ANY Nerf gun on Spudfiles.... So Now I give you a story:
Last year, At our swim team end-of-year party, we went to my friend Kendall's house and had a GIGANTIC Nerf war. I always got stuck with crappy guns, and got owned by the gun that I had made my friend Kendall that shot 100' plus.... I couldn't even touch him. So this year, I decided I needed to step up to the plate and make something so hardcore, that it would put fear in the hearts of my contenders by the sheer loading of it. And through various guns posted on this site, and a special 2 dollar sale for single acting cylinders at my local surplus store, I created the Gutmenduff:
TADAAA
Image

Specs:
Action: semi-automatic Spring-Magazine fed
Magazine Size:8+1 rounds
Propellant: Paintball HPA or CO2 tanks, Regged down to 60-120 PSI
Velocity: Enough to get a Good stefan 100' +, Or to puncture cardboard at the Highest velocity setting
Barrel: Removable 1/2in CPVC, 14in Long
Ammo: 1/2 FBR Nerf Stefans w/ one BB weight (see pics below)

Anyway, As you can see, Its FAR from a finished product. The epic battle is in a few months, so I have some time to make it Battleworthy, but as of now you can see it actually works! Some closeups:

Magwell Open
Image

Magwell Closed
Image

Ammo
Image

Magazine + Follower and custom Spring
Image

Loaded Magazine with Dart Retaining Pin
Image

Valve Area
Image

Cylinder Area
Image

And of Course, I must prove the semi-automatic Action with a Poorly made video! (notice how its denting the cardboard... This is at 60 PSI)

Image

And a Qestion to Mods: When I finally finish this gun up, Is it OK for me to make a completely new post?[/b]

EDIT: I forgot to add future plans. Future plans:

-New trigger system
-at least a 15 round magazine (and multiple magazines)
-get rid of hunks of aluminum hot glued to the side of the magwell
-get rid of tape holding extra force return rubber bands and replace with an extention spring
-A Vaccum Molded and Epoxy-reinforced outer shell (yes I have the stuff to do this)

Posted: Mon Jan 05, 2009 6:36 pm
by skyjive
Looks great, I like the mag hookup arrangement, and it seems very reliable, which is hard to do with semis. Its too bad you can't have a less awkward trigger setup, so you could use a blowgun or something instead of pushing that thing up and down. Might be kinda hard to keep on target.

Posted: Mon Jan 05, 2009 6:40 pm
by VH_man
thanks for the quick reply.

Theres a reason this is Mark 1.3.... I have a 3 Way valve and a super-special QEV to make my trigger system VERY sexy... All of these parts coming in in a few days.

Posted: Mon Jan 05, 2009 6:43 pm
by Sticky_Tape
Very nicely made gun and not such a bad video (mine suck).

Posted: Mon Jan 05, 2009 7:37 pm
by Hotwired
2 dollar sale for single acting cylinders
!!!!


On another less jealous note I see using the chamber pressure to operate a cylinder which closes the bolt is catching on.

There's a nice action on that one, good stuff.

Posted: Mon Jan 05, 2009 7:43 pm
by PVC Arsenal 17
Very nice! Reminds me of my recent work and Btrettel's FANG.

Edit: Looks likes your darts have already suffered a few pinches. Welcome to the wonderful world of using bolts to feed soft projectiles! Is the feeding reliable?

Posted: Mon Jan 05, 2009 7:59 pm
by VH_man
PVC Arsenal 17 wrote:Very nice! Reminds me of my recent work and Btrettel's FANG.
It was your guns with the cylinders that sparked my ideas! Truly awsome.

It pained me how you all attached your magazines though, which is actually the secondary reason I made this gun. I guess my weeks and weeks of working on homemade nerf guns pays off :-D

Now to post this on Nerf HQ and have people be like OMG I WANT YOUR BABIES BDIGIkdghdjnajdiaejadk1358e9789&*^&*^*

:D

Posted: Mon Jan 05, 2009 8:08 pm
by PVC Arsenal 17
NerfHQ/Haven aren't the smartest bunch. Mostly 12 year olds with no understanding of, well, anything. All they care about are looks. They drool over guns like the FAR but fail to realize how impractical they are.

And yes, my mag attachment was very awkward. It was going to be changed, though. It doesn't really matter anymore since I've put the project aside in favor a semi-auto shell system.

Posted: Mon Jan 05, 2009 8:09 pm
by Hotwired
A rotating bolt for a nerf gun is impractical? :D

Posted: Mon Jan 05, 2009 8:15 pm
by VH_man
when you can get twice the ROF and the same range with a system as such without shells, I see no need for shells other than the cool factor. And when it comes down to a Nerf battle, Its about how many darts you can lob downrange before you run out more than anything.....

Posted: Mon Jan 05, 2009 8:20 pm
by PVC Arsenal 17
VH_man wrote:when you can get twice the ROF and the same range with a system as such without shells, I see no need for shells other than the cool factor. And when it comes down to a Nerf battle, Its about how many darts you can lob downrange before you run out more than anything.....
Or you can get no RoF at all when chunks of sliced up foam are clogging your breech. :P

Who says shells have to slow things down? If you get too high a RoF using only foam ammo, you get chops like in a paintball gun. With shells, you can eliminate the bolt altogether. So if anything, shells provide a higher RoF.

Besides shells, there are other other approaches. I can't wait to see Btrettel's revolving barrel design.
Hotwired wrote:A rotating bolt for a nerf gun is impractical? :D
I'm not sure if you were being sarcastic, but why put all the time and effort into something that could be done easier? Waste is silly.

Posted: Mon Jan 05, 2009 8:23 pm
by btrettel
Looks nice. Maybe you can work out some of the kinks with this approach before I do so I don't have to work as hard. :wink:

My magazine was designed to be internal for simplicity. I understand most people might not like that, but it's fine for me. I'd suggest trying it.

As for the shells vs. no shells debate, I think shells make it more complicated, but I'd use them if they were the most reliable. My main problem is that they're annoying, but with some sort of chain they'd be manageable.

This might sound odd, but I recommend NOT posting at any of the major Nerf forums. To be honest, I'm embarrassed to have participated at either given their current state. PVC Arsenal is completely correct. One additional thing worth noting is that most people only care about spring Nerf guns, so your gas designs will be glossed over unless you are one of the big name people. If you do become one of the big name people though, expect 300+ replies to your concept threads, worship from the masses, and the full wrath of the ignorant who'll never cease to ask questions with obvious answers.

Posted: Mon Jan 05, 2009 8:30 pm
by VH_man
PVC Arsenal 17 wrote:
VH_man wrote:when you can get twice the ROF and the same range with a system as such without shells, I see no need for shells other than the cool factor. And when it comes down to a Nerf battle, Its about how many darts you can lob downrange before you run out more than anything.....
Or you can get no RoF at all when chunks of sliced up foam are clogging your breech. :P

Who says shells have to slow things down? If you get too high a RoF using only foam ammo, you get chops like in a paintball gun. With shells, you can eliminate the bolt altogether. So if anything, shells provide a higher RoF.
funny.... I had to do ALOT of work to not slice my darts. As you can see, I have some that got it a little bit.

I like the design. only thing I see wrong with it is that your probably going to want a small groove or something in the top of the "mag well" so that your shells don't simply shoot out the sides when the magazine pops in.

I might have to try this.... I have a single acting cylinder with a 1/2in stroke....... (VERY TINY)

Posted: Mon Jan 05, 2009 8:32 pm
by PVC Arsenal 17
A detent is a must. However if you make the breech slightly offset, the stack below the current shell will act as a detent.

Edit: I forgot to comment on your QEV. Your inlet to the barrel is located behind the breech. Is the bolt flow through? Or are you simply using the cylinder's rod (no close fit) and ignoring air lost out of the breech opening?

Posted: Mon Jan 05, 2009 8:34 pm
by MrCrowley
And a Qestion to Mods: When I finally finish this gun up, Is it OK for me to make a completely new post
How much are you going to pay me? :P

Yeah it'll be fine, cool stuff with the cannon by the way :)