I found the true importance of a chrono out today (not just for tuning)
My bobcat was playing up again, I had shot about 300 shots in one session and slowly throughout the session the POA had crept down. Because I had kept adjusting as I went I didn't really notice it that much except for getting frustrated at the lack of consistency I was getting.
I I ran it over the chrono last night and it was putting out 770fps with JSB 18's. I though that was a bit odd since I hadn't touched anything except for shooting it since I last chromed it with JSB 16's and it was doing 910fps. So I didn't believe the results. Until I tested it again this morning in better light and found it was reading the same.
So I pulled the gun out of the stock and undid the HST all the way out, counting the revolutions as I did. 7 revolutions until it was all the way out... Hmm... I know it needed 9 full turns in to get me to 890-900 fps so I wound it back in and re chronoed it... 900fps bang on... And it's shooting lights out!! The best accuracy I have ever had out of it. The drawing pin holding my target to the nacker didnt stand a chance. One shot and the target fell. (And the POA had to be lowered by about 3 MOA to get back to where it started before it went a but funny last weekend)
suffice to say I'm one happy shooter now! I wish I knew why it had undone itself though as no one else has access to the gun and I know I didn't adjust it.
One other thing... Everyone that said ST barrels don't like lube... Don't believe it... Try for yourself, I did (thanks to yess suggestion) and its tightened groups up even further. (The barrel does like to be cleaned as well) probably every tin of pellets or 2.
My bobcat was playing up again, I had shot about 300 shots in one session and slowly throughout the session the POA had crept down. Because I had kept adjusting as I went I didn't really notice it that much except for getting frustrated at the lack of consistency I was getting.
I I ran it over the chrono last night and it was putting out 770fps with JSB 18's. I though that was a bit odd since I hadn't touched anything except for shooting it since I last chromed it with JSB 16's and it was doing 910fps. So I didn't believe the results. Until I tested it again this morning in better light and found it was reading the same.
So I pulled the gun out of the stock and undid the HST all the way out, counting the revolutions as I did. 7 revolutions until it was all the way out... Hmm... I know it needed 9 full turns in to get me to 890-900 fps so I wound it back in and re chronoed it... 900fps bang on... And it's shooting lights out!! The best accuracy I have ever had out of it. The drawing pin holding my target to the nacker didnt stand a chance. One shot and the target fell. (And the POA had to be lowered by about 3 MOA to get back to where it started before it went a but funny last weekend)
suffice to say I'm one happy shooter now! I wish I knew why it had undone itself though as no one else has access to the gun and I know I didn't adjust it.
One other thing... Everyone that said ST barrels don't like lube... Don't believe it... Try for yourself, I did (thanks to yess suggestion) and its tightened groups up even further. (The barrel does like to be cleaned as well) probably every tin of pellets or 2.
