I went through the same ammo testing process several years ago with my Anschutz 1727. The rifle is easily the most accurate rifle I have but my initial groups showed some horizontal spread. I concluded that even slight changes in the wind cause significant wind drift. I changed my shooting so that I sent the rounds down range as fast as possible. I can send 4 shots down range on the same breath because of the Fortner action. Suddenly I started to consistently get half moa groups at 100 yards. The rifle preferred CCI TNT and 5 consecutive 4 shot groups measured .35 .36 .65 .72 .56 ctc. Hornady VMAX 17gr measured .61 .48 .78 .53 .80 ctc. I was shooting prone with a bipod and rear bag. I plan all my varmint shooting so that I shoot down wind. I never run a rod down the barrel. What I do is pull patches through using 80# monofilament fishing line on all my rifles. I learned this from shooting expensive air rifles.

While living in Alaska for 45-years, I learned that ALL wood products (construction lumber, furniture, gun stocks, etc) shrink continually due to the extremely dry climate in the winter. You gotta keep the action screws tight. I love wood, but almost all of my big game rifles have synthetic stocks! Just saying.....

I have the c455 17hmr and love it! So accurate - I reviewed the 22lr version which I also have and is identical

I think you nailed it with the reticle comment....subtension..

My 457 loves the remington 17gr accutip-v and the federal loaded with the 17gr vmax. It will shoot under 1/2" all day with those 2

I’ve been looking at this rifle for a while, thanks for your review. I find when shooting, the smaller the target you pick the better your accuracy. Try this. Instead of aiming for the red dot itself aim at six o’clock on the dot exactly where the red meets the black. That will give you a more precise target and hopefully precise results!

I have two guns in that caliber. The problem with accuracy is the progressive contamination of the gun barrel. Caliber 17 is extremely sensitive to dirt. that is the reason why the groups of fire diverge further and further. I clean the barrel of the rifle at least after 10 shots, otherwise the firing groups are bad. it's not a thermal problem, I've tested that extensively.

Thanks for the video! I own a 22lr. 457 Training riffle and I'm contemplating buying a .17 HMR conversion barrel

A good rule of thumb is that when your crosshairs are bigger than the target you are aiming at you can expect at least twice the diameter of that spot/target plus the accuracy or group size of the gun itself. It makes a huge difference with scopes and even bigger with open sights when aiming at too small of a target.

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acclamate the barrel with a few shots of a particular brand then shoot for groups, then move on to the next brand and repeat. Not sure what the scope your running, guessing an older Bushnell, I would consider an upgrade if that's the case. Still decent shooting.

If your reticle was covering the smaller circles it will make it difficult (impossible) to have a precise point of aim. With the larger circle you were likely able to see the edges of the circle and have a more precise point of aim.

So it's been a bit more than a year. How did things settle with this rifle? Did the accuracy come back, did you discover what the problem was? One thing is you REALLY need a better scope with a much higher magnification. At least16x, but preferably higher. You need much better target resolution when trying to shoot tight groups. You need to be able pick out a target on the target that is smaller than even the bullet holes. Doing that you can have EXACTLY the same aim point for each shot. Also it's best if you're not hitting the aim point, so dial your scope to hit below your aim point. Then when you're finished shooting groups you can put your point of aim and your impact back to the same place. If you destroy your aim point your eye will wander and your group will open up. Aim small, miss small.

Did you let the barrel cool down in between shooting the next group. if the barrel gets hot it might alter the groups. what was the weather condition like between the two that could have made a difference. might even be down to how you was feeling if thay was done on different days.

The most inconsistent thing on any gun range is a "human being"... We have days when we shoot very, very well and then we have those days when we can't seem to do anything right! I have the CZ 457 American in 17 HMR and most of the time using Hornady or CCI 17 grain V-max, it shoots .5 moa at 100 yards, but I have days when I'm not feeling that good and cannot produce consistent groups in that category! Of course, I'm much older than you are, so there's that. I am seriously looking at the 457 Varmint in 22 WMR to round out my CZ collection. I have a CZ 452 American that I have tested at 100 yards, 3 shot groups. She always throws a flier, but I glass bedded it over the weekend and tomorrow if the wind is friendly, I'll take her out for a test drive and see if bedding brings those fliers into the fold! It should... If I get the stock screw tension "just right", she shoots 3 into one hole at 55 yards, but staying in that "sweet spot" is a tricky business without a good bedding job! I haven't done anything to the 457 but shoot it. This winter, I'll take it down and adjust the trigger to 2 pounds and take a close look at possibly bedding it as well. It does a fair and consistent job as is, so .... My rim fires are all intended for hunting and all wear Leupold 3-9 VXII scopes, Burris rings. You have a nice range to shoot on there! Thanks for the friendly review...

I have 452 & 453 CZs and contrary to popular belief they don’t all shoot amazing right out of the box. 99.9% can be corrected with a competent glass bedding job. I owned one 452 that nothing helped. It was going to throw one flyer at least an inch away from the rest of the grouping. I sent it back to CZ: they shot it and and said they had no idea what was wrong with it and sent me a new rifle. It’s a very rare occasion that bedding won’t make a CZ shoot more consistently. It’s also going to shoot better ( more than likely) the more that you shoot it. You’re shooting copper jacketed bullets so a patch of Hoppes #9 is all I’d ever run through the barrel.

Could have been hot barrel if not allowed to cool between 5-shot cycles.

Check that your action is tight to your stock, shoot a group with the stock torqued to 15inch lbs then 17, 20, 23, 25 etc up to about 30lbs. That will have a effect Also did you clean it prior to shooting the barrel? Only use a good quality rod with a patch to remove any crud other than that don’t clean it until your accuracy goes to crap

What does HMR and WMR stand for.

If your rectacals are blocking the entire dot the you truelly don't know if you are being consistent. Probably the reason the one target was good is because you were centered in the black.

7,5 jouel??

Try lowering your trigger weight. I have a 455 American that couldn’t do better than 2” at 50 yds. Put a lighter spring on the trigger and groups went to 1/2” at 50 yds.

You could improve your groups by shooting some foulers before you shoot for groups. Maybe five of each on the center before shooting the O'clock positions for score. I'd also pull a patch between ammo's but you could probably skip that since they have jackets. I like 20x magnification for anything more than 50 yards especially for scoring. But i'm also old. 17 is not a match gun caliber. The guys that buy them are killing machines not accuracy nuts. Not much ammo to choose from. I have several CZ's in 22LR that will do 1 moa with some cheap ammo but most will perform best in that .12 cents up and ammo. Thanks for the vid. I watched it on the Big Screen.

which brand is scope rings?

Would benefit from bedding the action, shots are stringing a bit, fan of the gun though

You might get better groups after running the same amo through the barrel before trying to group with it

Just sold my 17 HMR rifle. Very disappointed by the accuracy of the round and more specifically, the inconsistency of the round from box to box. CCI makes 2 or 3 products in 17 HMR rounds and they all shoot so differently at point of impact. It's a frustrating round to work with and your video confirmed for me that I did the right thing by selling my 17 HMR rifle. Thanks...

Got to bed the round to the barrel first

would have been much better if a sudden range camera had been used tbh

Wow i dont like the texture on the grip. Sjhould've sticked with the checkering. Cosmetics aside it looks like a neat rifle.

I have heard the 455 and 457 are not as accurate as the 452-453 version due to non-threaded barrel and other factors according to gunsmiths. Get a quality scope, so important. I have a 453 in 4.4HMR with a Meopta R1 4-16X44 and it shoots 10mm groups at 100metres with CCI 1.1 gram rounds all day. Never had any issue with needing to clean the barrel more regularly. With every rifle you have the lottery, no two rifles shoot exactly the same. Only downfall is wind.

I don’t think it’s the gun, every cz I’ve shot is very accurate, maybe you rushed it a bit or just had one of those days, can’t judge off one 5 round group especially if you shot sub Moa before with the same gun. Could be the scope needs a change or just some more trigger time.. good video cz makes amazing rifles! I would do a round 2 and let the barrel cool between brands of ammo, what do you have to lose you got the gun and Ammo just shoot make a second video. 🍻

The CZ American stock is very soft Shift in pressure or pressure location Can n will change the point of aim My CZ455 American shoot like crap Until I finally threw the stock away MDT 22 LSS chassis and Lilja barrel Finally got my 17HMR Consistently moa or sub moa

Scope is too big for that gun

I purchased a 17 some years ago, complete waste of money, absolutely useless for target shooting as you have to clean the barrel every 20 rounds, or it just won’t group. They won’t tell you this in the gun shop though!..

You need to learn the specs before you video. Invest in a scope, at least what the rifle cost. Learn how to properly set up scope also.