where did you pick up the tank and regulator and how much?
where did you pick up the tank and regulator and how much?
I tested the efficiency at various hammer spring preloads today, using the 15.9 gr. JSB Exact Jumbo pellets which are very accurate in this gun.... The new slimmer Delrin valve has picked up about 2 FPE, so it shoots the 15.9 gr. pellets at nearly the same velocity as it did the 14.3 gr.... I had to back the preload out several turns relative to the stock poppet because the harder Delrin is much easier to knock open than the soft seal on the stock valve.... Here are the results....
The efficiency seems slightly higher than before, and the plateau starts at 6 turns out instead of 3.5 turns.... Based on the results, I tried a short string at 6.5 turns out, and the velocity was only about 10 fps below the plateau and the efficiency was about 1.10 FPE/CI.... I think that's pretty good for a QB79 shooting at 25 FPE, and it's likely where I will end up tuning it.... That should give me over 70 shots per fill....
Bob
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal: Too many to count!
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