Scope center and zero question ?

josh19 · May 20, 2016

Hi, I am new into optics. Brought several scopes including this Nikon prostaff (4-12x40mm) that I put on the AR15 and try to zero the scope for 25 yds today. I can not even hit the paper. The more I played with elevation and windage, the more messed up it seems. So after researching on the web. I followed these step by step procedures at home

1. Center the scope first using the mirror method as well as counting the clicks from both end and divide the full range (# of clicks) by 2 for both elevation and windage to get the center of the scope.

https://www.youtube.com/watch?v=zpfCfgzpy80

2. Then I use the laser boresighter (laserlyte) to roughly zero the scope before I go to the range again. I heard this will save time and ammo to get on paper.

https://www.youtube.com/watch?v=MTpRCiKkeq8

I then try to move the cross hair so that it line up with the laser dot on the wall.

Problem I ran into: I ran out of both windage and elevaton range to play with. i.e I can not move the cross hair any further to the RIGHT and DOWN to line up with the laser dot. It max out. See pics below.

Wonder what I did wrong ? Many thanks

( Also tried it on Mueller 8-32 x 44 scope, also ran into the same range issue). I thought by center both scope, it will take care of it. But it did not.

kalister1 · May 20, 2016

Laser dot is NOT very accurate. I have the BULLET with a Laser in it type. I can take it out and put it back in and it shows up in a different location on the cross hairs while pointed at the garage door.
Scope rings and Mount may NOT be perfectly aligned with the bore. Sometimes Shimming the mount (Place Thin Metal Shim between mount and rifle) could be required depending on tolerances of Rifle and Mounts.
Rifle barrel will point UP to allow for bullet drop. Scope height off of Center Line of rifle barrel affects where Laser DOT and Scope Cross hairs align at different distances.
Having said all that, My dot will be very close to center line of cross hairs and a little low while in the garage. Not as far off as our picture. It appears to me you will need to shim the mount? I am NOT an expert, I am sure some will be along.

davsco · May 20, 2016

separate the upper, pull the bolt, steady the upper and look thru the barrel at something 25+ yards away (soda can, top of fence post, actual target, etc). then move the scope til it's centered on that "target."

also post a pic of your scope mounted on the rifle. if you're actually running out of elevation or windage room on the scope, perhaps mounted incorrectly.

INMY01TA · May 20, 2016

What he said ^^. Just look down tbe barrel w/the bolt removed. If that don't work it'sprobably mounted wrong.

ted76 · May 20, 2016

I have bought bases before that were labeled for my rifle that fit but would not allow the scope too be zeroed, bought another set of bases and problem solved.

Sticky · May 20, 2016

davsco said:
separate the upper, pull the bolt, steady the upper and look thru the barrel at something 25+ yards away (soda can, top of fence post, actual target, etc). then move the scope til it's centered on that "target."

also post a pic of your scope mounted on the rifle. if you're actually running out of elevation or windage room on the scope, perhaps mounted incorrectly.

That's how I 'boresight' a bolt or AR rifle... just remove the bolt or on an AR, separate the upper from the lower, remove the bcg and CH and mount the upper on a steady rest. Align the bore with a distant object (I use about 50yds as a starting distance) and then dial the scope to the same target. On paper at 25-50yds, little tweaking to fine tune it and then back out to 100 and readjust as needed.

josh19 · May 21, 2016

Thanks for the good advises. The method of using the upper, pull the BCG to bore sight it sounds good. My misconception was that you can only do it to bolt rifle. Now I have to improvise something to hold the upper steady.

Those high end scope like Nikon, Mueller seems to give me most problem. I just brought a UTG UTG 3-9X32 1" BugBuster Scope, AO, RGB Mil-dot that came with quick release mount ($75). I used laserlyte and the red dot and cross hair line up pretty fast. Well, moment of true is when live fire in the range. But I think this should at least get me on paper.

outrider58 · May 21, 2016

josh19 said:
Hi, I am new into optics. Brought several scopes including this Nikon prostaff (4-12x40mm) that I put on the AR15 and try to zero the scope for 25 yds today. I can not even hit the paper. The more I played with elevation and windage, the more messed up it seems. So after researching on the web. I followed these step by step procedures at home

1. Center the scope first using the mirror method as well as counting the clicks from both end and divide the full range (# of clicks) by 2 for both elevation and windage to get the center of the scope.

https://www.youtube.com/watch?v=zpfCfgzpy80

2. Then I use the laser boresighter (laserlyte) to roughly zero the scope before I go to the range again. I heard this will save time and ammo to get on paper.

https://www.youtube.com/watch?v=MTpRCiKkeq8

I then try to move the cross hair so that it line up with the laser dot on the wall.

Problem I ran into: I ran out of both windage and elevaton range to play with. i.e I can not move the cross hair any further to the RIGHT and DOWN to line up with the laser dot. It max out. See pics below.

Wonder what I did wrong ? Many thanks

( Also tried it on Mueller 8-32 x 44 scope, also ran into the same range issue). I thought by center both scope, it will take care of it. But it did not.

You are probably too close to the wall you are shining your laser on. Use the method suggested by davsco. That's all I ever do. Just make sure you are sighting on an object at least 25yds. away.

Magnumite · Jun 5, 2016

I like using the laser sighter if I change sights or optics. Cowitnessing an optic to sights or vice versa isn't an issue. Checking the zero before removing the old sight/scope allows me to set the replacement closer to zero.

antco · Jun 5, 2016

davsco said:
separate the upper, pull the bolt, steady the upper and look thru the barrel at something 25+ yards away (soda can, top of fence post, actual target, etc). then move the scope til it's centered on that "target."

That's exactly how I do it. I then reinstall the bolt and shoot at a 25 yard target and adjust in as necessary. From there I jump out to 100 yards and it's game on.

My last sight-in had me shooting a 5-shot group smaller than a dime at 100 yards on shots 6-10.

Those laser devices are unnecessary.

JWLaRue · Jun 6, 2016

You may also wish to try either/both swapping rings (front-to-back and back-to-front) as well as turning rings around (left-to-right).

-Jeff

Copper · Jun 6, 2016

It must be the rifle, remove the scope and rings, clean them thoroughly, then throw away your ar and mount on an ak :innocent0

outrider58 · Jun 6, 2016

All this resurrection and still no word from the OP. I love a mystery.

Tnt9506 · Jun 6, 2016

Not sure about the op but I at least got some good info from here.

Sent from my SM-G900V using Tapatalk

mike_in_md · Jun 6, 2016

Aim at the impact area with no target. Watch where the bullet hits the dirt in relation to the center of the scope. Adjust scope.

DaemonAssassin · Jun 6, 2016

OP, if you are still having issues getting on target, while at the range, I do have at least one idea. Disassembly of the the upper to remove the barrel. After that, you will need to lap the face of the upper receiver with a lapping tool. Lapping the face, trues the face of the receiver so that the barrel sits against the upper in a straight plane. It increases accuracy and also will allow you to have an easier time zeroing the rifle.

Ask around on MDS for help with lapping the upper receiver face, somebody is bound to have a lapping tool. :innocent0

Another thought is that the scope mount is loose on the rail. If that is the case, then all you need to do is tighten it down.

My last thought is that your scope ring screws that hold the scope in the rings are loose. You don't have to torque the daylights out of them, you just have to get them tight enough, that they will stay in place.

jrumann59 · Jun 8, 2016

DaemonAssassin said:
OP, if you are still having issues getting on target, while at the range, I do have at least one idea. Disassembly of the the upper to remove the barrel. After that, you will need to lap the face of the upper receiver with a lapping tool. Lapping the face, trues the face of the receiver so that the barrel sits against the upper in a straight plane. It increases accuracy and also will allow you to have an easier time zeroing the rifle.

Ask around on MDS for help with lapping the upper receiver face, somebody is bound to have a lapping tool.

Another thought is that the scope mount is loose on the rail. If that is the case, then all you need to do is tighten it down.

My last thought is that your scope ring screws that hold the scope in the rings are loose. You don't have to torque the daylights out of them, you just have to get them tight enough, that they will stay in place.

While lapping is good to do and helps accuracy if a receiver face is as off as his is perceived to be lapping is not going to help. A couple of mils of anodizing is not going to be noticed at less than 200 yards.

pwoolford · Jun 8, 2016

Sounds like he was way too close to the paper. Either that or a bad mount.

outrider58 · Jun 8, 2016

pwoolford said:
Sounds like he was way too close to the paper. Either that or a bad mount.

My feeling as well.

Scope center and zero question ?

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