I finally broke down and purchased a tank (a Great White with all the trimmings from Joe B) and having a source besides the Hill pump has enabled me to do some tuning on my AA200T (.177).
The 200T shoots about 575fps out-of-the-box with it's most accurate pellet (H&N Match 8.18 gr) according to my chrony which is a Combro. Admittedly, it's inexpensive as chronys go and I have not compared it with any others accuracy-wise, but it does work ok and once I figured out how best to place it on the end of the barrel it rarely gives an err reading.
In addition to changing the hammer spring and transfer port choke screw settings, I added a Huma External type regulator to the pressure cylinder. With current settings, the rifle shoots a bit over 700fps for about 9 ft lbs of energy. I could go a good bit higher especially with an air source like the Great White, but I only have about 30 yards available to shoot, I don't hunt or 'pest' with it, and it also matches nicely with my springer' power level (a Rob Hawkins tuned HW35 with Macarri spring).
After a couple of shot strings, I'm wondering if the results I'm getting might be considered a good outcome. Here's a summary:
190 bar fill
57 shots before it's off the reg
avg 711.5 fps
es avg about 12.5 fps (first string 9; second string 16)
sd 4.95 fps (had to check this twice as, amazingly, it was exactly 4.95 for each string!)
off reg at little over 100 bar (maybe 105 ish)
I notice that if I throw out the first several shots (starts a bit high) as well as the last few, limiting the string to more like 50 shots, the ES would drop a little and the SD would tighten a little.
Topped with a SWFA SS10x42, this is a very accurate rifle producing sub half inch groups at 30 yards. No aspirin tablet is safe in my backyard!
So, is this a good result or should I be hoping for lower ES and SD? What do you think?
The 200T shoots about 575fps out-of-the-box with it's most accurate pellet (H&N Match 8.18 gr) according to my chrony which is a Combro. Admittedly, it's inexpensive as chronys go and I have not compared it with any others accuracy-wise, but it does work ok and once I figured out how best to place it on the end of the barrel it rarely gives an err reading.
In addition to changing the hammer spring and transfer port choke screw settings, I added a Huma External type regulator to the pressure cylinder. With current settings, the rifle shoots a bit over 700fps for about 9 ft lbs of energy. I could go a good bit higher especially with an air source like the Great White, but I only have about 30 yards available to shoot, I don't hunt or 'pest' with it, and it also matches nicely with my springer' power level (a Rob Hawkins tuned HW35 with Macarri spring).
After a couple of shot strings, I'm wondering if the results I'm getting might be considered a good outcome. Here's a summary:
190 bar fill
57 shots before it's off the reg
avg 711.5 fps
es avg about 12.5 fps (first string 9; second string 16)
sd 4.95 fps (had to check this twice as, amazingly, it was exactly 4.95 for each string!)
off reg at little over 100 bar (maybe 105 ish)
I notice that if I throw out the first several shots (starts a bit high) as well as the last few, limiting the string to more like 50 shots, the ES would drop a little and the SD would tighten a little.
Topped with a SWFA SS10x42, this is a very accurate rifle producing sub half inch groups at 30 yards. No aspirin tablet is safe in my backyard!
So, is this a good result or should I be hoping for lower ES and SD? What do you think?
