Rimfire Central Firearm Forum banner

Windage off at distance

2K views 19 replies 14 participants last post by  edwea 
#1 ·
Took the cz 457 American down to the 50 yard range today to stretch it out a bit. I normally shoot at 25 yards and have my scope zeroed for 25. It did not disappoint, the groups looked the same at 50 as 25, pretty much a ragged hole. I expected them to open up a little, but they were surprisingly tight. My problem was this-I had to make nearly 2 inches of windage adjustment at 50 yards. I expected a little drop, but not windage adjustment. I assume it is because the scope is at an angle to the barrel. My question is how do I align the scope and barrel properly? I would like to only need to adjust for elevation and not windage. The set up in question is a cz 457 American topped with a Nikon Prostaff rimfire 3-9 in Leupold rings. Thanks in advance.
 
#6 · (Edited)
First thing to try in seeing if turning 1 ring so the clamp is on the other side helps. You could try lapping the rings straight, Wheeler and others sell kits for lapping rings. Then there is filing or shimming.

Lastly you could try to find some windage adjustable rings. I have a set that have a clamp screw on both sides of the rings ( US Optics) , and a set on a TC Contender were the front ring swivels, held in with a set screw and the rear ring is in a dovetail with a clamp screw on each side to swing the rear of the scope left and right.

Weaver sells adjustable rings, so do others. Most likely you will need a picitinny rail to mount adjustable rings.

Edit: 2" off at 50 yards equals about .001" per inch that the scope are rings apart. It won't take much to get back in alignment.
 
#7 ·
Verify your crosshairs on the scope are vertical (+) and not canted to the bore. Any error in this will cause a shift in windage from the original sight-in distance. Pull the bolt and verify the vertical crosshair is centered in the bore. As far as the scope not aligned with the barrel you will lose some adjustment for windage. This is where your rings or dovetail need corrected.
 
#10 ·
Tend to agree with other posters that say to check that crosshairs are truly level, not canted somewhat; the further from the original scope 25 yard zero, the more it will be in error. If this doesn't correct things, Burris makes rings with polymer inserts to correct for either windage or elevation, depending on where you position them. They have worked extremely well on a CF heavy varmint rifle I own, and saved me from having to buy a +20 degree canted scope rail. Good luck.
 
#14 ·
Here is my theory; based on some experience. Obviously check that you scope is securely mounted (and I'm assuming you've done that). Next, either your scope is mounted in the rings out of plumb. Or your gun is canted when you pull the trigger. At only 50 yards I believe it is most likely your scope is mis-mounted. You can check this easily with a spirit level. Level you gun and then check to see that you scope is level. I use 300 WSM cartridiges (resting on the stock- top of the barrel channel lips) to make a bridge for my level above the barrel; level the gun; then check the scope. Adjust as necessary. (move carefully here)

You can do the same bridge/level when you shoot to make sure the gun is level on the bench.

There is a clever trick using a plumb line drawn on a target at 100 yards or so. With the point of aim at the bottom of the paper, draw a plumb line on the paper up 35 inches. (looks like an upside down lolipop) Dial in 30 MOA up on the scope and shoot at the point of aim at the bottom. When you gun is level and your scope is level the bullit should strike on the line- 30 moa high. If not, experiment and see if you can improve. Hold you gun different or twist the scope in the rings.
 
#17 ·
There is a clever trick using a plumb line drawn on a target at 100 yards or so. With the point of aim at the bottom of the paper, draw a plumb line on the paper up 35 inches. (looks like an upside down lolipop) Dial in 30 MOA up on the scope and shoot at the point of aim at the bottom. When you gun is level and your scope is level the bullit should strike on the line- 30 moa high. If not, experiment and see if you can improve. Hold you gun different or twist the scope in the rings.
Very good, Stan. But you do not "hold the gun different" during the Tall Target Test, you make sure your reticle is parallel to the plumb-bob string every shot.
Then if you are off you must twist the scope in the rings to fix it.
 
#18 ·
Buy a SiteLite Laser Boresighter and solve your problems without other solutions that may or may not work. You can use it on many different calibers it is very accurate and you know immediately if the scope isn’t aligned with the bore. Your first shot will be close to the target bullseye and a few clicks horizontally or vertically will have you ready to go. I would recommend the SL 150 with the kit. You will need nothing further.
 
#19 ·
I had the pleasure of hitting my 50 yd range this weekend and was somewhat pleased with my results. Here's what I did to the rifle: I noticed that there was contact between the barrel and the stock. Actually enough that if I pushed the barrel or stock to one side, it would hold in that position (putting pressure on the barrel I presume). I took the action out of the stock and lightly sanded the barrel channel a little bit. Just enough to open it up the entire length back to the receiver. I can now run a dollar bill (probably 2 actually) along the length of the barrel. I resighted it in at 25 yds and then went out to 50. My groups were just as tight as ever, about .3" center to center at 50 yards. My drop was the same, as expected. My windage was off less than half of what it was before. I'm going to say it was about an inch to the left of poa. I re-zeroed the scope at 50. While this may be unacceptable to some, this is a squirrel gun and it is certainly minute of squirrel. I have other rigs for the bench work. I will probably leave it alone for now as these results with this gun are acceptable to me at this point in time. If I do anything else to it, it will probably be to turn one of the rings around and see what that does. Thanks for all suggestions!:F
 
#20 ·
I swapped the scope on this rifle this weekend and hit the range and now think I know exactly what the issue was, so thought I would share. Scope was a Nikon Prostaff Rimfire and was replaced with a Leupold with an adjustable objective. Problem disappeared and rifle is boringly accurate with no adjustment necessary between 25 and 50 yards. Now here's what was happening: when I switched to 50 yard shooting with the Nikon, I manually adjusted the parallax by TURNING the objective lens. Since the point of aim wasn't perfectly in the center of the lens, the image shifted just enough for me to be off at the target. With the new ao scope, when I adjust the parallax, the objective lens doesn't turn but rather moves forward or back in a lens carrier. This doesn't distort the image and point of aim relative to the target remains the same.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top