Mikeyb,I appreciate your enthusiasm. Please share chrony data with your rifle. I'm pretty much done with any testing now. I'm still waiting for a day with good weather when I have time to shoot to work on my marksmanship. I really liked the results I got from the 0.128 spring but I still have the 0.125 spring in it. Also, as I said, I think pellet weights between 20 and 25 gr are ideal for this rifle in .25 cal. I'd love to hear other's opinion and experiences with this subject.If I made any adjustments to the vortex piston, I'd reduce the gas pressure. I wouldn't increase the pressure. I have a hard time shooting that rifle accurately. I think the OEM stock pressure is more than enough for this rifle. This is totally outside of anything I'm will to do but I wonder about tweaking the dimensions of the transfer port- such as rounding out the edges maybe making it a wee bit wider. But I won't be attempting anything like that.