Right now I am looking for an alternative of the "air-cylinder-way", that is easier and more compact (and I like moving parts at the breech
).I thought that with a blow-back-breech, where the the weight of the bolt and the spring (aka rubber-band...) is tweaked that way, that the o-ringed bolt opens the mag-port just after the projectile left the barrel, similar performance could be achieved.
The self made DCV/3way-valve is made differently to most commercial sold ones and the one that MRR made. Instead of pushing the bolt in the direction of the exhaust-port, it is pulled away from it to open it, like in TECH's QDV's.
By doing this I was hoping to have some "faster-opening-QDV-style"- effect. But this seems not to be the case, because of:
a very long/heavy bolt,
three (floating!) o-ring's (much friction),
and the force of the "return-spring" (yes I know it's rubberbands...)
Here is a video of the 3way working quite well.
The blowback isn't moving in the first video because it needs about minimum 12 bar to work and a round in the barrel.
But it moves in the second one, which I will add soon (having problems with youtube...).
...I had only a hand-pump there, so I couldn't do 12 bar semi shots...
[youtube][/youtube]
Next thing I will do is filming the breech-action in high-speed to see if the breech is "slow enough"
