centering crosshairs/scope w/ mirror?
has anyone done this? ,,, remember read once about centering scopes cross hairs using mirror…i hve RWS 34…WAS very accurate…its a breah barrel…let my dumbass brother shoot…well he tryed cocking gun over his knee b4 i could stop him..well barrel stuck..took apart put it back together now it works…but now accuracy is toast..removed muzzle break..still shit.@ 15meters throws pellets all over…bench rest used… cant see how the knee cocking..would effect poi at all??during this i had droped scope bout 2 foot fall to grass…SOOoo..i scearh of problem…thought maybe scope was problem…i have lowest setting on scope…bout 1 foot from mirror..crosshairs way off..the “reflected’ view shows hairs left and high does anyone know process w/ mirror the aline hairs….THANKS guys for any help you can PM me..if not wishing to take fourm space
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okay, here is the only tidbit of sense I can make of it thanks to Pabs adding ‘shooting’ the gun to the procedure.
So you optically center the scope
then you shoot it mounted on the rifle
POI is not on the vertical crosshair
you loosen the rings and rotate the scope to correct the error
shoot again and the POI is on the vertical crosshair
scope is optically located above the bore
adjust vertical turret
confirm at longer range
Everybody happy 🙂 group hugs and all that stuff……
may try this next gun I mount a scope.
WHOA 😀 …thamks to all… very interesting… centering hairs in scope just lets one “know” it ‘s alinnged through scope… and if mounted straight w/ rilfe bore..it aims where the cross hairs show..if off in any way even slightly i would think that i way our eyes see our brains would try the “adjust” and mtght create an illiusion akin to a parallax …not an eye doc…but main point is simply you what to hit where the scope is centered or better said zeroed..so if they are not alinged in scope …..ya see 😉 have fun ya’ll
Pab,
Centering the reticle is by far the simplest way to do exactly that, get it mounted properly.
How else do you know if the scope is centered over the bore??? The reticle has to be in the center of the scope.
Jim
Urrgggh, brain…getting…it….
Center the scope, mount the scope, should shoot windage correct. If not then shim the scope.
Having only owned rimfire and air rifles, range has always been relatively short and hence centering the scope has little gain. For long range stuff I can see the advantage. 💡
Pab,
Centering the reticle is by far the simplest way to do exactly that, get it mounted properly.
How else do you know if the scope is centered over the bore??? The reticle has to be in the center of the scope.
Jim
Say I zero my guns at 40 yards.
If I shoot at any distance less than that then the error caused by my scope/ bore being offset issue is going to be somewhere between the offset and zero (at 20 yards it will be half the error).
So if my scope is off 1/8″ (probably way more than it really is) Were talking about 1/16″ of an inch at 20 yards.
I’m not going to invest in adjustable mount’s or lapping mount’s to work out some minor error I’ll never notice but have a good chance of making worse.
Be happy to…
but I think it would be easier on everyone if you just Googled (or Binged or whatever-ed) “mounting a rifle scope properly”.
I think you’ll find that centering the reticle is one of the steps that a riflesmith will use.
Regards,
Jim
If the scope isn’t sitting on the rifle straight to begin with, it doesn’t matter what you do with the scope, you’ll still get crossover at different ranges. How can centering the scope help this?
the trouble in his example is corrected by having the bore accurately located below the scope and the crosshairs vertical.
Hey Voltar,
I contend that the easiest way to locate the bore accurately below the scope and crosshairs is to center the scope before it is mounted. It’s way easier to shim the scope than to shim the barrel.
Regards,
Jim
please explain cause I ain’t gettin’ it. 🙂
the trouble in his example is corrected by having the bore accurately located below the scope and the crosshairs vertical.
Hey Voltar,
I contend that the easiest way to locate the bore accurately below the scope and crosshairs is to center the scope before it is mounted. It’s way easier to shim the scope than to shim the barrel.
Regards,
Jim
Right Walt – and on an AF rifle any cant error is magnified because of the scope/bore height.
I purposely twisted my scope a little while the rings were loose. It forces the shooter to cant the gun slightly. I found this more accurate either side of my POI before I locked everything down. I just have to keep the crosshairs level to my eye and everything works.
Just goes to show… theory without practice is pointless.
TOm Gaylord is pretty full of it.
the trouble in his example is corrected by having the bore accurately located below the scope and the crosshairs vertical.
EXCERPT from our hero Tom Gaylord
complete article http://www.pyramydair.com/scope-shift-barrel-drop.shtml
3. Shooting at different ranges
This one is so common, yet so deviously subtle at the same time. Most shooters figure if they mount a scope on a rifle and level the horizontal reticle, the shot groups will adjust straight up or down when the scope’s elevation is changed. No, they won’t! In fact, they’ll almost never do this without something being done to the scope first. That something is called optical centering of the reticle.
All three groups of five shots were fired with the same aimpoint – the center of the bullseye! The scope was zeroed at 20-30 yards. The group at 10 yards is low and to the right of the vertical reticle that passes through the center of the bull from 12 o’clock to 6 o’clock. The group at 40 yards is lower and to the left of that line. This scope was not optically centered, so the groups do not stay on the vertical reticle. If the scope were adjusted up so the groups would be at the correct elevation, they would still fall on either side of the centerline.
The barrel of a rifle almost never looks in the same direction as the scope. The difference is usually too small to see, but it’s there. If you zero the rifle for 20 yards, the groups will be LOW AND TO THE RIGHT at 10 yards and LOW AND TO THE LEFT at 40 yards! (Note: It can also be just the opposite – left and right.) You can re-zero the scope all day long – this relationship will never change. Some people will remount their scope, then they switch with other rings, then they swap the rear rings for the front, all in a vain attempt to correct what is easily corrected by optically centering the scope.
I don’t know if the above is BS or not, I do know I had an adjustable mount up/down left/right front and rear. My POI was like the above pic.
I have since replaced that mount and its much better now.
If your groups are like the above, then there is a problem. Bad barrel, bad scope, bad scope mounting, time to clean barrel..ect
This is just another trouble shooting tool.
I did not take the scope off the gun to do it! Rubberbands holding one of the girls little powder mirrors to the front of the scope and a light was all that was needed. Did not take 5 minutes.
Voltar is right..if your guns shooting perfect at all ranges..don’t screw with it, its pointless.
If you get a new scope or are swapping them around and re-sighting in or just curious (you don’t have to adjust your crosshairs) then why not.
After all if good old Tom recomends i..its gotta be good 🙄 🙄 🙄
If alignment error’s are the concern for optically centering a scope then that is the first step and not just a matter “oh its optically centered so I’m all set”… Cant just optically center your $40 chinese scope in $8 leapers ring’s and be all set because you optically centered it.
Optical centering also assumes that the optical components of the scope are in perfect alignment with the outer tube. In many cases and especially with the cheaper (relatively) scopes the majority of air gunners use they are not.
I just dont think that its that big an issue – 550 yards maybe, with a gun that never came with scope mounts and they had to be added later, but 55 yards with a scope rail that was machined into the gun by the people who made it… no, I know I dont hear people complaining about it.
I’m actually quite surprised this is not a standard (or even recognized) procedure by many here.
Considering the use of airguns is generally considered a precision sport, and that we use them at ranges from under 10 yards to over 100 yds, the potential for windage errors introduced by an optic not mounted properly are immense. This is not the case for 10m rifles as they only have to have one distance where the line of sight and trajectory of the pellet have to intersect. Please understand I mean this in the horizontal plane, as I am a “clicker” and move my reticle vertically for distance.
Imagine, if you will, a scoped mounted extremely incorrectly, say at a 45 deg angle (like 10:00 on the rifle) Could you then see the lack of accuracy as a result? Even though the reticle is horizontal or vertical, at the distance between the convergence of POA and POI moving the turrets to the indicated left will move the pellet to the left, however, passed the POI/POA it will move in the opposite direction. You could only have the rifle POA and POI meet at one yardage. The fact that you are only “a little off” just means the error is smaller, but certainly still exists.
You really need to have the scope centered optically before you can mount it properly. Considering it takes all of about a minute to center one optically, in my estimation, it is an essential step to an accurate rifle.
Regards,
Jim
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Sounds good to me.
😀 😀
Jim