My CZ453 (a model 452 with a factory installed single set trigger) is fairly accurate and I supposed you could say that it's "all tricked out". I had my gunsmith pillar-bed the two action screws, glass-bed the entire action and re-float the heavy barrel (mine is a CZ453 "Varmint" model .22 rimfire).
I haven't got an adjustable pounds/inches torque screw-driver yet, but I'm looking for one, so I've got the rear action screw pretty darned tight and the front action screw a little less tight (I'm guessing the rear screw is about 25 lb/inches and the front screw is about 21 or 22 lb/inches).
I've topped the rifle off with a 4-12x40mm with adjustable A/O, middle priced ($289 scope that I found on line for $190) variable center-fire scope that gives me all of the magnification I need to shoot regularly at 50 yards and occasionally at 100 yards. The scope is very clear and the images are very sharp.
After testing over 30 different brands/bullet-types of .22 rimfire ammo over a two year period, I found my rifle "likes" Wolf Match/Target the best. It is reasonably accurate with CCI Mini-Mags (hollow points), Super-X solid points and a few other "normal" (not "target" or "match" ammo) .22 ammo, but of course with "normal" .22 rimfire ammo, I get "fliers" here and there due to the manufacturer's lack of precision in putting their .22 rimfire ammo together.
I have the "set" trigger adjusted down to a few ounces and on a windless day, I can easily keep all 5 shots inside a bright orange target paster (1" pasters) at 50 yards. Groups (50 yards) generally run about .2 of an inch center-to-center with an occasional group somewhat smaller or larger.
At 100 yards, (no or very little head-or-tail wind)... I can easily hit small (3/4 inch?) pieces of broken clay birds 8 or 9 times out of 10 shots and misses are generally my fault rather than the rifle, but I suspect the ammo has something to do with that as well unless I'm using Wolf Match/Target ammo which is rare since it is so expensive these days.
I mostly shoot either CCI Mini-Mags or Federal "Classic" 38 grain, copper-plated H.P., high-velocity long rifle ammo (Lot#GH350) of which I purchased a case several years ago because they were the most accurate rounds tested in my 70+ year old Remington Model 512 and my 50+ year old (serial# 9xx) Ruger 10/22. At this point-in-time, I'm down to just two boxes of the Federal cartridges left... I shall miss them when they're gone.
I've found that I must hold about 4-inches high at 100 yards when my scope's crosshairs are sighted in the center of the little pasters @ 50 yards. I use the paster as a 10 ring (at 50 yards) which I stick on a 9" white paper plate. I generally put 5 pasters on a plate and, at 50 yards, most all of the shots are inside the pasters with a "flier" here and there... depending on what ammo I'm using that day.
I'm convinced those "fliers" are due to a lack of the manufacture's quality control because I've weighed the rounds and grouped the rounds by weight and the thickness of their rims, but still I get a few fliers with the good ("normal", not "Wolf match/target" ammo) .22 rimfire ammo, but even with the Wolf Match/Target, I still get a few "fliers" now and then.
Naturally, all the above shooting is off the bench with the rifle supported by a heavy cast aluminum Lyman rifle rest with sandbags (25# shotbags I've filled with sand) on the rifle rest and at the toe of the butt-stock.
With all of the above in mind, I'd suggest that the maximum effective range of a .22 rimfire rifle depends on the skill of the rifleman plus the REAL accuracy of his rifle and ammunition.
I've never shot a .22 rimfire rifle beyond 100 yards, so I can't say if it is "good" beyond that range or not. However, at 50 yards or less, my CZ453 is most certainly within a "minute-of-squirrel's-head" and easily inside a squirrel's vital body parts at 100 yards IF the I have estimated that range correctly.
However, in truth, I wouldn't take a 100 yard shot on a living animal with a .22 rimfire, I'd use my heavy-barreled Sako in .222 with a 24x scope which has fired a 5-shot group of less than 1/10th of an inch using my handloads. The Sako is extremely accurate for shots out to 225 yards. Beyond that, bullet drop becomes drastic.
That said, remember that it is ALWAYS easier to shoot half-inch groups with a keyboard than with a rifle... and it is DEFINITELY easier to shoot quarter-inch groups with a keyboard than with a rifle.
Strength & Honor...
Ron T.
