SpudFiles

Maybe i could use heat-shrink tube to make a good seal and get the spin on the bb.

Basically, my valve is a sort of re-useable burst disk, but that does not bursts and can be triggered by a light pull of trigger (much easier then on spring guns as there is only 6lbs of pressure on the "piston") The advantage is that it's an in-line valve.

I don't know anything about these things you call burst disks

DavidVaini looks at his BDC design and says, "oh wait, yeah i do!"

lol

Sounds interesting, cant wait to see it finished..


As far as heat shrink tube, I think it wont hold up. But I have no idea since I havnt played with heat shrink stuff too much.

Well, after some re-calculation and for a more convenient use ( i diminushed the psi to make easier cocking, even tough it will be later adjustable )

I get 412 fps with .43 , 460 fps with .3 and 499 fps with .25

BUT ...

I think that the hop-up may slow down the fps down a little. Is it possible?
(Or maybe not as it is at the start of the barrel, i just dont know)

EDIT:

After re-crushing numbers, i found that the gun would perform best if i used 100 psi and one pump at 30lbs of effort ... I would get 525 fps with .28, wich is good enough i think .

The hopup will slow the BB down a little bit but any loss in velocity will easily be made up for in the range you gain from the the backspin. Also when it comes to accuracy high quality BBs as well as a good barrel will play a big part. This might help you with the hopup as it shows some of the internals of a good sniper hopup, marks some of the most important things to make a good hopup and also shows that you should be able to just use one screw with no gearing to get a good adjustment. http://www.airsoftretreat.com/forums/in ... ic=86871.0 Also heat shrink might work but it might be a bit hard, which might be fine with higher velocities, and a bit thin, which can be solved by using two or three layers.

Do a 450 fps with .3 gram 6mm pistol needs to have a hop-up? It wont be shooting further then 80 feets (with iron sights) .

I wonder if at that short ranges an hop-up is needed (It would make the design simpler) .

I would say it probably isn't necessary if 80 feet is as far as you will be shooting. I shoot .25's at about that range without using hop-up, and my gun shoots at a lower velocity than 450 fps.

I would say it probably isn't necessary if 80 feet is as far as you will be shooting.

Well, its an estimation of the furthest range i can shoot a soda can with a pistol standing up ...

Is 25 meters hitting a soda can reasonable while standing up with a pistol ? No wind or hop-up and .3g 6mm airsoft. I mean, can we stand steady enough for it?

It will probably have the velocity to go that far, but it might not have the accuracy to reliably hit a soda can at that range.

I really feel this needs to be pointed out;

Have you considered to, instead of one 30 or 40 lb pump to have two 15 or 20 lb pumps? The effect is the same. Also, remember that in fact it won't be 30lbs the whole way through but just as the very very end(i am assuming this is air as a power source and nto say a spring which is different).

Good luck on this, sounds like a fun one, also if this is just for messing around (no clue about airsoft, so i might be way off!!!) can't you also use those nice little steel balls which they sell cheap as dirt on ebay? I reckon that would make things more like you seem to desire them to be.

can you use it in a real air soft game