How accuracy will change - day to day

horseman2

horseman2

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My original experience was with a CZ452 Varmint and later a CZ452 American (perhaps an Australian with the Beachwood stock).
I was always testing them with CCI MiniMags both solids and HP's.
The short end of the stick is that one day the preference was for HP's and the next time out . . . solids.
Same lot numbers would change performance.
Sold them both so as to buy a Remington 40XBR but eventually replaced them with a CZ455 American and then a CZ455 Varmint.
They are now both wearing Burris 4.5 - 14 x 42 Fullfield II with the Ballistic Plex Reticle scopes.
Yesterday the American would not shoot the same lot of solids worth crap - two groups at 100 yards was over 2".
The Varmint shooting HP's produced a 1.08 and a 0.99 at 100 yards.
Quit while I was ahead with the varmint and there is still another day with the American.
For a while I thought they both preferred solids and gave all the HP's to my son.
I also tried a bunch of difference standard velocity bullets trying to put together some 5 shot groups. One has to look a long time to find the right combination.
 
I have a article somewhere, temperature and humidity play a huge part in the performance of rimfire ammo, top competitors in the USA, where the stakes are high, will be seen with 3 or 4 lot numbers of their go to ammo on the bench, they will watch the temperature and humidity and pick their ammo accordingly, some times different lot numbers from morning to afternoon as conditions change.
Best advice is to take notes of temperature and humidity with your test targets of ammo types and lot numbers, then match the best ammo to the conditions your being faced with in real time.
 
PM sent, read the article, for you it's free. if anyone else wants in on it I'll post it in the EE lol
 
the humidity and temperature will also affect your rifle. high humidity will cause a wood stock to swell creating pressure points on the action and barrel . depending where you store your rifles and where you shoot , time of the year and location all will be factors.
 
I've had similar experiences as the OP with my CZ rifles. On some days I might shoot one very well, and on others not so good. I make the following suggestions based on my own experience and advice that is consistently echoed on the CZ section of RFC, where many very experienced shooters share their considerable knowledge.

The first thing to do is to use better ammo. CCI Minimags, be they solid or HP, are not going to give you the best accuracy your rifle can deliver. Use affordable match grade ammo such as SK Standard Plus, and it will give you a fighting chance of putting the shots where they are supposed to go. This suggestion is all the more important if you are shooting at 100 yards. Subsonic ammo, that is ammo that stays below the speed of sound, yields the best accuracy with .22lr.

Another thing to keep in mind is that stock flex is a very real bugaboo with many .22lr rifles. Often the way they sit on the rest or bags can cause uneven stress that will cause wider groupings, and they will be even wider at longer distances. My own experience has shown me that it is very important to make sure, as you move from bull to bull on your target, that the rifle is set up evenly on the rest/bags, without the slightest "twisting" or uneven pressure. Additionally, many CZ will shoot more consistently off a rest if you lay the rifle on the front rest just a little forward of the magazine. Here, it will likely be least "hold sensitive".

On a related note, the original Varmint stock is better for shooting from the bench than the American because it has a wider fore stock, but neither is ideal for shooting off a rest, especially the American, with its tapered, relatively narrow, round fore arm. Make sure that the front rest prevents sideway "wobble" which is often a problem with CZ's like the American, Lux, or Super Match. I use a piece of leather on the front rest that can be folded double when necessary that makes the bag "grip" a little tighter on the fore stock or fore arm.
 
grauhanen said:
I've had similar experiences as the OP with my CZ rifles. On some days I might shoot one very well, and on others not so good. I make the following suggestions based on my own experience and advice that is consistently echoed on the CZ section of RFC, where many very experienced shooters share their considerable knowledge.

The first thing to do is to use better ammo. CCI Minimags, be they solid or HP, are not going to give you the best accuracy your rifle can deliver. Use affordable match grade ammo such as SK Standard Plus, and it will give you a fighting chance of putting the shots where they are supposed to go. This suggestion is all the more important if you are shooting at 100 yards. Subsonic ammo, that is ammo that stays below the speed of sound, yields the best accuracy with .22lr.

Another thing to keep in mind is that stock flex is a very real bugaboo with many .22lr rifles. Often the way they sit on the rest or bags can cause uneven stress that will cause wider groupings, and they will be even wider at longer distances. My own experience has shown me that it is very important to make sure, as you move from bull to bull on your target, that the rifle is set up evenly on the rest/bags, without the slightest "twisting" or uneven pressure. Additionally, many CZ will shoot more consistently off a rest if you lay the rifle on the front rest just a little forward of the magazine. Here, it will likely be least "hold sensitive".

On a related note, the original Varmint stock is better for shooting from the bench than the American because it has a wider fore stock, but neither is ideal for shooting off a rest, especially the American, with its tapered, relatively narrow, round fore arm. Make sure that the front rest prevents sideway "wobble" which is often a problem with CZ's like the American, Lux, or Super Match. I use a piece of leather on the front rest that can be folded double when necessary that makes the bag "grip" a little tighter on the fore stock or fore arm.
Click to expand...

^excellent points for sure. If you shoot anything like I do..don't rule-out the possibility that you're the weak link in the equation some of the time. I sometimes shoot exceptionally well one day....then not the next. Same conditions/temperature/ammo/rifle etc. I've also learned (rimfire and centerfire) that over a long shooting session....even a few hours...there is a "PEAK" in the accuracy about 30-60 minutes in.....then about the 2.5-3 hour mark...things start to open up a bit. I've always thought this was a result in part, or in whole, to shooter fatigue. I think there is a physical component to that...but also an attention span one as well. I can hit the end of a long shooting session....a little frustrated by the last groups...then notice I'm not sitting the same way, the rifle isn't sitting on the rest the same way when I started, etc. Usually...I find myself leaning forward at the beginning of a session....then maybe my back gets sore~I end-up in a more upright position. I seldom move the front rest, so the forward 2"-3"end of the stock is JUST on it by a bit. Definitely not the way I start-off.

Ammo~yes, this is key for sure....but I was looking for grauhanen to mention how wind can impact the slower-moving bullets @ any distance...let alone...100 yards. It's been proven that good subsonic ammo will out-shoot the high velocity stuff every time, but @ 100 yards...you need very good conditions, good technique, a good trigger and the right ammo. I'm sure you've seen subsonic ammo actually flying through the air while shooting with that nice, clear Burris. If it's moving slow enough that your eye can actually catch a glimpse of it...imagine what even a little gust of wind will do.

Scope (parallax)~if your Burris is the one I think it is, it has an adjustable objective. Assuming you've got that set at the range you're shooting at....I'd still look for parallax issues. If you don't know how, the most simple way is to get the rifle on a solid rest, then without touching it...look through the scope and physically move your head up/down, left/right in small movements to see if the reticle appears to move. If it does...even a tiny bit, make very small adjustments in the AO and re-check. I've had scopes that needed to be set @ 90 yards on a 100 yard range....and vice versa. If you're getting even a tiny bit of parallax error...it's nearly impossible to get tight groups because from one shot to the next....the relationship between your eye/reticle/target is different. Every time.

I'm no expert in this stuff....just a guy who has made every mistake at least a dozen times. :) If you knew all of this already, then I sure don't mean to offend by stating the obvious. Just trying to help! :)
 
Thank you all for your comments.
Right now I need more time to read in depth.
I consider both of these rifles to be "gopher guns" and therefore shooting off Harris bi-pods and keeping them sighted in with the MiniMags.
CZ455 Varmint with Burris scope:

With one batch of standard velocity (Lapua Midas Plus) performing extremely well, I caught a fly patrolling an adjoining target at 50 yards . . . would have made an interesting picture as on wing was adhered to the paper.
 
As Yodave mention correctly Temps/Humidity.

Also I was taught to follow the light(sun). If lowlight aim low, bright aim high, sun right- aim right, etc.

There are some nuances to that general rule and the best way is to log every shot and all the environmentals and make up your own mind as to effects you see.
 
.22LRGUY said:
Ammo~yes, this is key for sure....but I was looking for grauhanen to mention how wind can impact the slower-moving bullets @ any distance...let alone...100 yards. It's been proven that good subsonic ammo will out-shoot the high velocity stuff every time, but @ 100 yards...you need very good conditions, good technique, a good trigger and the right ammo. I'm sure you've seen subsonic ammo actually flying through the air while shooting with that nice, clear Burris. If it's moving slow enough that your eye can actually catch a glimpse of it...imagine what even a little gust of wind will do.
Click to expand...
Wind is a factor that increases with distance, and doping for wind when shooting .22lr is a big topic in itself. The thing with HV .22lr ammo is that it starts out over the speed of sound and at about 75 yards it is in the trans sonic zone where projectile instability becomes a very real impediment to accuracy. To be consistent, a round needs to stay supersonic or alternatively stay subsonic, and that's something only the slower moving match .22lr ammo can do.

horseman2, just this morning I was shooting my CZ455 thumbhole Varmint (but didn't see any flies). I experienced some very good groups and some that I wouldn't care to post. I know that what caused the variation between good and not-so-good was mostly how I was holding the rifle and how it was sitting on the rest and rear bag. It's not always easy to correct. I often feel like it can be compared to golfing (which I used to do) in that I usually had a pretty good idea what I was doing wrong but correcting for it was easier said than done. Ammo, how consistently the rifle is "held" , and wind are always the key factors in accuracy when shooting .22lr at longer distances, taking for granted, of course that the rifle is good.

horseman2 said:
With one batch of standard velocity (Lapua Midas Plus) performing extremely well, I caught a fly patrolling an adjoining target at 50 yards . . . would have made an interesting picture as on wing was adhered to the paper.
Click to expand...

No wings remained on this fly at 58 yards on Thanksgiving Day a few weeks ago, the first "kill" with my 1710 HB.

 
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