Yesterday I hardened the hammer, and today I made a new plunger for my Dual Power Adjuster with only 0.10" of travel instead of 0.25".... There is still 0.25" of screw adjustment in addition to that.... It took a lot of fiddling with the dimensions, but I got it so that with the adjusting screw out 5 turns the bolt will just drop into the new locking slot on the breech.... which puts maximum compression on the hammer spring.... At full in on the adjuster and on low power, I only get 350 fps.... so I've got the whole range covered on my 1500 psi regulated setup.... I added a spring loaded plunger inside to insure that the adjuster wouldn't change from low to high power on it's own.... as there is no pressure on it from the hammer spring with the gun uncocked on the lower power settings.... Here are the parts....
The bolt is sitting in the high power notch.... You can see a small hole drilled in the top of the adjuster.... It is an indicator that is covered on high power and visible behind the rear plug on low power.... You assemble the adjuster and install it with the rear plug, and then install the plunger and spring and secure them with the set screw.... Here is a photo of the assembly set on low power....
Since the new hammer has more travel and weight.... and also can put more compression on the hammer spring.... the gun can now be setup for more than 1500 psi.... When I tried the maximum settings on my gun, the velocity basically peaked with over half the travel still remaining on the adjuster on high power.... Here is a graph of the velocities on both high and low power....
Since the adjusting screw is 20 TPI, two turns on the screw is the same as the difference between high and low power.... For example, 1 turn out on high power is the same at three turns out on low power, about 845 fps.... At 1500 psi, the velocity peaks at 2 turns out on high power, and 4 turns out on low power.... In other testing, I have found that adding hammer strike after the velocity peaks only wastes air.... There is no question this was occurring, as at 4-5 turns out on high power, this thing was LOUD.... I wanted the least hammer hit I could get and still be right at or near the plateau.... so I was obviously looking at 2 turns or less.... I tried 1.5 turns and the velocity was down 20 fps to 880.... I ended up using 1.7 turns out and achieved the following results....
The linear trendline shows about a 9 fps loss as the pressure in the tank decreases, which is only 1%.... but the shape of the curve is interesting.... The peak velocity occurs not at 3000 psi tank pressure, but at about 2600.... In addition, the velocity doesn't drop below 880 fps (3% below peak) until the pressure in the tank has dropped to 1200 psi.... which is 300 psi BELOW the regulator setpoint.... This hammer strike is so perfect for this setup that the valve is self-regulating within the tiny amount of regulator creep and below the setpoint.... From past experience with regulated guns I knew this was the best way to not only get the longest shot string, but the best efiiciency as well.... I wasn't disappointed.... I achieved 60 shots averaging 896 fps with 18.1 gr. JSB Exact Heavy pellets.... That's 32.2 FPE x 60 = 1943 FPE total.... This used 1800 / 14.5 = 124 bar of air from the 13 CI tank.... which is 1614 CI.... The efficiency has jumped to 1.20 FPE/CI.... and the shot string on this gun since initial setup has gone from 37 shots to 44, and now to 60 shots at virtually the same power.... 
Now it was time to find out what it did on the low power setting.... I filled the gun to 2000 psi, turned the adjusting knob, and started shooting.... I did two 30 shots strings before the pressure dropped to 1400 psi.... That's 60 shots on 600 psi of air.... 10 psi per shot.... Then I kept shooting as I wanted to see what happened to the velocity below the regulator setpoint, as I expected it to climb.... Here are the results....
Above the regulator setpoint, the velocity averaged 638 fps with the 18.1 gr. JSBs for the first 60 shots.... Once the pressure dropped below the regulator setpoint, the velocity began to climb.... It displayed a classic bell-curve, behaving like an unregulated PCP, peaking at nearly 790 fps at 1000 psi before dropping back below the velocity it was shooting regulated at about 600 psi.... This part of the curve is useless for our purpose, but I wanted to show everyone what happens when you have a very weak hammer hit on a regulated gun.... This gun, from 3000 psi down to 1500, will now produce about 150 shots at 16.3 FPE, which is 2445 FPE of energy from 1345 CI of air.... That works out to an astounding efficiency of 1.82 FPE/CI.... The gun is VERY quiet set up this way, because it's just sipping a tiny amount of 1500 psi air per shot.... The downside is that the SD is quite large at about 12, and the extreme spread is about 40 fps (7%) at 2000 psi and above.... This makes this a good plinking and short range setup.... but you would probably notice some small vertical stringing in the groups beyond 25-30 yards.... I think the reason for this is that any TINY variation in the hammer strike will change the amount of air released by the valve by a relatively large amount in percentage terms.... If you wanted to set up this gun to shoot at 16 FPE all the time.... you could reduce the regulator pressure to about 650-700 psi and then balance the hammer strike to that.... I'm guessing you might lose a bit of efficiency (high pressure tends to be more efficient).... but the extreme velocity spread and SD would be much tighter.... Alternately, if you had a 1000 psi regulator, this gun could be setup for about 800 fps.... and at 1200 psi it could be setup in the high 800s.... However, by using 1500 psi the efficiency is better....
This has turned out to be a very interesting project that not only successfully developed my Dual Power Adjuster.... but it also resulted in a High Power Hammer as well.... To really put that through it's paces will require much higher pressures.... I have a feeling that this could be the perfect setup for DerekVinyard's 3000 psi tubes.... One thing for sure, if the current hammer spring won't cut it.... I have one twice as stiff that I'm sure will.... 
Bob
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