F1 Chrony - Just ordered a used one

Well this airgunning disease continues to progress. I have been playing with Chairgun and Strelok Pro, testing pellets, cross winds, angles, and temperature swings. I just broke down and got a used F1 Chronograph on EvilBay. It is an old one but I got a decent deal on it I think, and it will hopefully work well. It does not have the newer metal bar and plastic diffusers, but the old metal shoot through face plates and plate diffusers. I read there have not been many changes to these over the years, and the old ones and new are basically the same unit. It should be here next week.

I have been calculating my FPS off of pellet drop, but am looking forward to getting more accurate results for plugging into my programs and printing out some accurate charts. I also really want to have a base line for my gun so I can keep an eye on the spring, and can better determine when it needs to be replaced.

Is being .25 of an inch off really worth it? This is all like an itch I just have to keep scratching. I don't get this crazy over my centerfire guns! LOL