GB Semi

[frankrede]

Wow, truly amazing.
I love the handle.
Dam, why don't I can't I think up things like these.

[pyromaniac]

clide if you don't have rubber just put an old comforter behind the target. works for me.

I just have to say that's on helluva nice gun.

i watched the the video and when you started shooting I though uh oh hes going to hit the house.

[paaiyan]

I like it, the bolt design is nice. Is there some sort of shock-absorbant material behind the bolt to absorb the impact when it's opened?

[clide]

Updated the first post with an animation.

There is no bumper for the piston because of a lack of room, but the bolt does have a bumper of sorts. The stop that stops the forward movement is a sheet of rubber that slides inside the bolt housing.

rmich: Yeah, it was initially put there to help the ROF, but I discovered that it is to some extent necessary so the pressure behind the piston doesn't increase too much when the valve opens. The valve would need some changes and take up more room if it were to operate properly without the secondary chamber.


Edit: <b>New video added.</b>

Also, please ask if you have any questions about the valve or anything else on the gun. I'll be happy to elaborate on anything.

[clide]

Sorry for the double post, but I just want to make sure people see all the updates. I just updated the pictures and added some new ones after cleaning up the gun and smoothing out some of the rough edges.

[bboymatty]

very very nice man great work, i would love to see this miniaturized down to the size of maybe a marble gun or something.

[clide]

I may build a similar design into a Tic-Tac gun at some point, but that is a ways back in things to do list.

[iknowmy3tables]

holy #$&^#$!%#@%#^#$%$%@#$ @#%#^ @##^%#$@#$5
that gun is so innovative so unique, and sounds like a bitch when shooting I don't think my gun can get away with the one of a kind bolt and semi blowgun, cause this is so amazing, well made and :crybaby: oh god why can't I machine stuff i don't even know how to use O-rings :crybaby:

[lukemc]

ummm ok this gun is realy awsome but the valve confuses me. why does it move back because the pressure against the front part of the piston is the same as the pressure against the back part. why does it move at all?

[clide]

The back part is just slightly larger, enough to create about 10 lbs of force pushing it back when in the closed position.


Oh and I have some good news. Today I was tweaking with it and managed to get the auto mode to work. I was able to shoot a full clip (13 balls) going full auto. Unfortunately I didn't have the video camera on that time and the loading mechanism started giving me fits after that. I'll tweak with the loading mechanism some more and hopefully have a full auto video up soon.

[jackssmirkingrevenge]

excellent use of the blow-forward valve, I really should incorporate it in one of my designs some day. Lovely damage shots too, though is the power a little inconsistent? Some of the GBs just slam through, others appear to ricochet.

[clide]

Well when one hits it makes a fairly small dent in the front but knocks a large area loose on the back side. When one hits these large weakened areas it will go right through. I think if I would have gotten some particle board it would have gone right through each time, because it wouldn't have been having to knock the big areas loose in the back.

[GalFisk]

Interesting valve, I think it could be streamlined to fit inside a tee.
It seems like the opening time will be much slower than traditional valves though, owing to the much smaller imbalance between the forces acting on the piston. If you're willing to sacrifice the air in the pilot, that could be fixed.
Impressive work as always.

[)DEMON(]

Wow, very impressive. You have once again made and amazing cannon. The big brother of your semi auto

You don't come here a lot but when you do you there's always something new for us to learn.

Love your blow forward design by the way, very interesting.

[iknowmy3tables]

okay I've just taken a bottle of chill pills with vodka and I think I'll be alright
now I can talk seriously
tell me what prevents the valve from acting in a full auto sequence patern when the triger is pulled