After seeing Minte posting about Crosmans tune ups he does for what I think is a very reasonable price I had to take him up to do a tune on my 2250b.
He started with doing a test of 48 shots to see how it performed through the Chronograph. I have attached a graph of 47 shots (not including the first one to get the valve filled with CO2). I quite surprised by it getting close the 550 fps that Crosman quote with 519 fps and being pretty consistent for the first 30 odd shots, with it sitting over 8 Ft-Lbs for most of those. Minite did state that he used Accupell which are quite light at 14.6gr.
From there the 2250 has been dismantled, the valve disassembled and the gas port ground out to remove the elbow to allow a smoother transition of gas. The valve cap has had a few threads removed to allow more gas into the valve.
A little photo run down on, thanks Mintie for the photos.
Mintie had put it all back together but was not happy with the results of 9.8 FPE up from 8.6 FPE, this is about 550 fps at the muzzle. The shot count dropped down to 20. He is having a think about it and I am sure he will find the problem.