I agree.... It would seem that having the lightest possible breech would use up less of the hammer energy.... ie deliver more of it to the top hat and hence the valve.... I have not frequented the Air Force oriented forums.... but I wonder if anyone has explored the relationship between the OD of the valve stem and the ID of the breech.... It seems that the greater the difference, the more force there is to open the valve once it is cracked and there is pressure inside the breech.... but that leads to an increased chance of a tank dump.... but also requires less hammer strike.... Some of the valves, like Doug's .25 cal, appear to use the same diameter OD on the valve stem as the ID of the breech…. As I see it, that results in no "assist" for the hammer in creating valve dwell, which means a heavier hammer required, and possibly more spring as well.... On the other hand, it should mean little chance of a tank dump, and no need for a mondo valve spring.... Lots of variables, and a lot to learn....Bob
Seems outside my sphere of interest at the moment, but thanks....Bob
<snip>In this case, the commonly available American sized O-ring, with a 0.070" CS, was much too thick for my .257 Condor.... I might work fine in a .22 cal where you wanted to detune it and extend the shot string, but all it did was lose me a lot of power.... However, the 1 mm CS O-ring was just about perfect for this gun.... It requires the PW setting to be increased by 1 to get the same velocity, but extends the shot string and increases the efficiency at the same time.... What's not to like.... !?!?!Bob
It's a little hard to envisage your 2-tank setup, so I don't feel I can offer any advice or opinion on that, sorry....Bob
I had thought of using a tubular plenum, large enough to hold about 150 cc (for a .257) with a reversed 300 bar bottle under it, and the regulator built vertically into the buttstock.... Something like this sketch.... An 10" length of MRod tube would be 145 cc, which is big enough for a .257.... <snip>