Diana Bandit pistol. Need a tune ?

For the price,a great pistol, paid $ 179. Shoots straight, easy to use. A plinker, 20-25 shots. Grip bulky but I got used to it. Fair trigger.I am still working on it. Crazy chrono tests: High 865, low 626, avg 734, ES 239 ! There is no sweet spot, the fps drop like a rock. I am concerned BUT at 50 yards I am getting 2-3 inch groups using 8.2 JSB At 100 yards I am still hitting my target, just have to keep slightly raising site as i shoot 25 shots. I got what I paid for. This has been a fun pistol. 

However,anyone have any experience with tuning this pistol ?

Any suggestions how to tune it to get the ES down ?


 
Hi John,

I too just purchased a Diana Bandit pistol and experienced the same wild chrono readings that you described. My highs were in the 860's and the lows were 623 too.

I thought my chronograph needed a new battery! After reading your post I'll have to check it again. My Bandit is getting groups similar to yours and I hope someone will shed some light on how to get the ES a little tighter and any tips on tuning this great little pistol. For $179 it's one of the best PCP pistols on the market! Thanks for posting, you kept me from wasting a battery in the chrono! 👍
 
I would go to the hardware store and buy some springs for the hammer. My goal would be to get my first shot through the chrono to be in the 500-600fps range. Then I would see what that shot string looks like and go from there. If you are getting over 800fps from that short barrel, that hammer is crushing that valve. That's why your current shot string looks like a tire going flat. Way too much hammer strike.