QB78 .22

[mackeral5]

I pulled this one out of the safe and decided to see how it does at 100yards.  It is a QB78 with the predecessor to the Gauntlet, a repeater breech that takes Mrod mags.  it is built on a 25" SS tube from Don Cothran.  Valve is equipped with one of my 2mm stemmed peek poppets and a cobra chamber.  An in-tube huma reg is set at 117bar.  It has approximately 17cc of plenum.  The hammer is all peek, weighing in around 14-17grams or so with the hammer pin, its been a while so I don't recall exactly what it weighs.  A K.I.S.S. SSG drives the hammer.  Tuned at JSB 18.13gr running 905FPS it gets in the neighborhood of 30-35 shots on a full fill.  Barrel is issue QB that has seen its share of JB bore paste and a touched up crown.  A DonnyFL Tanto mounts to a threaded muzzle adapter from Rocker1. Not the prettiest gun, but it is one of my favorite projects. 



Since this one had never been stretched out so far I really didn't know what to expect.  It ran out of up adjustment so I had to add 4 layers of beer can to the rear scope mount.  Once it was zeroed I made my first attempt at a 5 shot group.





Not terrible, I really didn't know what to expect so I shot another.



After this one I thought oh well that's good enough.  I was honestly disappointed in my favorite gun.....

Before putting it back in the safe I decided to see what the chronograph has to say about this one.  It is usually very consistent, so I was assuming I just had a bad barrel.  First shot over the chrony was 791fps.  That's strange, so I shot another 792fps.  Then I remembered the last time I shot this one I dialed it way back to get more shots while letting friends shoot at 20 yards....

I put a few turns of preload on the SSG and got velocity up around 905fps and decided to give it another go.  Rezeroed for the extra velocity (probably don't need all those layers of beer can any more, lol)...and shot another target.

This time much better.  I'm not going to try and move the group over, since I was able to do that already with the Flex submission. 



In hindsight those first groups aren't too bad for a gun detuned over 100fps with nothing more than HST adjustment....

My shooting just got cheaper as I really enjoy this little nitrogen sipper.  Another interesting point is that I forgot just how effective the DonnyFL Tanto is on a 30fpe gun.  This thing is quiet.

[jentry]

I enjoyed your write-up. Your tune sounds like something I want whenever I purchase a PCP.

Thanks for sharing.

[mackeral5]

I enjoyed your write-up. Your tune sounds like something I want whenever I purchase a PCP.

Thanks for sharing.

Thank you Jentry.  I've enjoyed shooting this gun over the last several days.