I've decided to pickup a new 22 bolt action. My goal is to start shooting competition at my local club. The rules are that we will shoot at 25, 50 and 100 yards. The rifle must be under 500 dollars new. I've tried a lot of different ammo in my Ruger American Rimfire and while it is extremely accurate at 25 and 50 yards it's lacking at 100. I've been doing quite a bit of research but am still having a difficult time making a decision. I have it narrowed down to a CZ 452 or 455. The hard part is that the 455 can be had new with either a heavy barrel or a standard barrel. The 452's can only be bought new with a standard barrel. From my research I have gathered that the 452's tend to be a bit more accurate than the 455's. I have tried to research if there are any real benefits of a heavy barrel on a 22 rifle but opinions seem to vary. I would like to try looking at it from another angle. Are there any NEGATIVES to a heavy barrel on a 22lr other than the rifle weighing more and being a bit more expensive? Also, which would you suggest for my intended purpose? 455 standard, 455 heavy or 452 standard?