How the 9mm airsoft rifle will work.....

[VH_man]

Well, ive been getting a few PM's lately about the gun mentioned in my sig.

basically, this is a BIG Gas Blowback SMG, with the valve placed behind the gun..... anyway ill explain how that works later.

basically, i will be using something simmilar to Jack's blow-foward bolt system, exept it will look simmilar to an AEG, seeing as i want to integrate this seamlessly into my old, broken AEG.

and another thing i am doing is instead of using the type of mechanism used on this gun:
http://www.spudfiles.com/forums/full-au ... t4108.html

i will be using a poppet check valve as a hammer valve. basically, when the blow-foward bolt reaches the rear position, it will open up the check valve with a long stick i will add on the rear of it, and release air into the blow-foward cylinder, make it go foward, fire a bb, then return to its original state, where it will open the check valve once again. to stop the cycle, stop airflow to the check valve......

another idea for the main valve would have been a rubber ball pushing up against an opening, wich i might have to look into, as it might be easier to open and a little more compact. it would also allow me to stay with my goal of makig the gun 100% metal, as to allow the use of high pressures...

i will have drawings up soon, but if anyone knows a free program that makes animated gif's, let me know, it would be eaiser to explain this if the parts were moving...............

the whole blow-foward cylinder will be constructed out of precision brass tubing, and some epoxy, if i can ever get it to look and work as good as jack does..................

also, i need a good way to run this thing. i was thinking of making a green gas adapter and just popping in a whole can of green gas, but the cooldown caused by such a high-gas consumption would ruin my preformance. the only other idea i had is to use regulated CO2. a little out of my price range, but it will definetly work, seeing as regulated, im using little to no gas per shot in relation to the co2 tank.............

[spud yeti]

Sounds bloody marvelous
I really like the whole concept, but surely its fully automatic, not semi-auto, since to stop the cycle you disconnect the air, not stop triggering?
I hope the concept works because its sounds really good.
What ROF are you hoping for and what speeds approximately?
Good luck for construction

[VH_man]

i was going to have it actuated electronically and have an uber-complex blowback mechanism, but...... i stand by the KISS principle, although it would have been cool, seing as i could computer control the entire thing, and make it have semi auto, 2 shot burst, 3 shot burst, 4 shot burst, 5 shot burst ect, as well as full auto with whatever ROF i choose............. but like i said it was to complicated and had parts under high stresses, and it would have been a gas hog.

yes, to stop the cycle by stopping the airflow. the trigger will most likely be a good old blowgun...............

as for ROF, im looking for about 10-15 shots per second. as long as its not a strafer im ok. ive got 3 500 round magazines for my old AEG, and i think becuase i can carrt almost 1500 bb's into a skirmish that a high ROF should be ok............

as for FPS, i will come to that road when i get there. i might have to put a secondary regulator so i can adjust the guns running pressure, thus allowing me to control the FPS preficely. should be nice when i go to the airsoft place near my house....... cause yes, this will be my primary.......

[origin unknown]

Here is a diagram that will usually only make sense if you look at JSRs diagram. This diagram I made shows how VH_man's design is full auto. There is no doubt that it will cycle in full auto. I might have used this instead of a pop off valve on a gun I plan to make, but due to the theoretical high ROF of your design I am not sure what to do because I want something that creates about 500-700 RPM
BTW: You said in an earlier post that you made a prototype one of these that shot at a very high ROF. Can you estimate what the ROF was?

[iPaintball]

Sounds awesome, but how is this a 9mm?

[thespeedycicada]

looks sweet cant wait to see it.

[VH_man]

I am using Parts from a 9mm Airsoft SMG, so therefore it is a "replica" of a 9mm SMG. it is 6mm.....

i think youre talking about the blow-foward bolt i made out of brass tubing for a nerf gun. it worked quite great............ however it kinda broke and eventually wore down becuase i drilled the holes horribly, and used sandblasting stuff instead of graphite to lube it.............

and thank you Originunknown, thats better than any drawing i could make......... and thats exactly my idea, exept the bolt will be smaller in diameter than jacks, about the same diameter as an AEG piston cylinder. it will also be built of brass tubing. im guessing that if i mix my epoxy right, i might be able to run this thing at over 250 PSI...... wich would own........

(JK) for controlling the ROF, you could always make a roller-delayed blowback system... (jk)

the only idea i have for ROF control is to use the electronic method mentioned before. my plan for this gun is to use as little gas as possible per shot, becuse nobody likes paying for gas........... the pop-valve uses too much gas for my liking........

another advantage is the only sound this gun will make comes from the muzzle, so it can be silenced effectively............

[jackssmirkingrevenge]

Very interesting, and the fact that you're closing off the air supply (ingenious btw) means that this has a much better chance of going full auto than my design ever did.

My one complaint however would be that the power is going to be less than spectacular - since you've shut off the air, the only air that's going to be available to fire the projectile is that inside the piston chamber - very economical with gas but unless you have a large chamber it's not going to spit it out with a lot of force, especially considering the said chamber is expanding and therefore the pressure is dropping.

[mopherman]

Are you sure the force of the spring will be enough to open a check valve with high pressure behind it? I love this design btw, very smart.

[jackssmirkingrevenge]

Are you sure the force of the spring will be enough to open a check valve with high pressure behind it?

good point but I'm sure the momentum of the relatively heavy bolt will be sufficient to open the valve.

[us sniper]

I think that you need to add a spring to push the ball back in the beginning. If there is no spring no air will be able to propel the bolt in the first place, otherwise It is a cool design. I am making a similar valve, but I plan to make it semi-auto and out of copper. This is what i am talking about.

http://s153.photobucket.com/albums/s240 ... cValve.jpg

[jackssmirkingrevenge]

If there is no spring no air will be able to propel the bolt in the first place

when the bolt is at rest, it will be holding the check valve open.

[us sniper]

The system that he is using with the ball sort of reminds me of this;

http://www.ultratwistedpaintball.biz/mm ... mation.gif

[VH_man]

yes, i actua,lly based this off of one of those air-hogs engines....... exept backwards and a little modified. air hogs engines have the same ball style check valve system........

and the spring i will be using is a spring i got out of an AEG that was upgraded, so i will have part of an m100 spring as my recoil spring. if this doesnt work, i also have springs from old spring pistols, wich are weaker.

the only thing i am worried about in this design is the high-speeds of wich the bolt will cycle. does anyone think it might get a little hot? i am designing this to have the bolt part removeable, in the event that it breaks.........

[jackssmirkingrevenge]

does anyone think it might get a little hot?

Nah mate, s'air-cooled n'all innit?