Winding Out of Windage While Bore Sighting

[Gwion]

So, here is the dilemma.

New scope, Sightron S-tac 2.5-17.5x56 mounted on a Talley Pic-rail in Talley Tactical 30mm rings, which have been lapped.

Bore sighted at 10m and only have 6MOA remaining to the right windage!

This scope had an issue new and has just arrived back from supplier as a warranty repair. The previous issue was with a failure of the parallax focus. That issue has been fixed but i lost confidence with the scope. Not an issue with the brand, just seems this scope was made at 4:30 on a Friday arvo and the boss had shouted a parma and pots for lunch.... you get my drift. A certain failure rate happens in all manufacturing.

So. Anyone got some tips for trouble shooting this issue??? I have a feeling it may be the scope but is there anything i can double and triple check with the mounting system or what have you???

I'd hate to have to buy new rings, these ones cost me a packet as it is!!!

[Apollo]

How high above the rifle bore is the scope centre bore...???

Why in the world would you try and zero at 10 metres, could be completely out of range on most scopes.

Put the scope back to "Zero" ie centre both windage and elevation. Set a target at 50m but better 100m and look through the bore to get target centred, look through scope and it should be close, especially windage. If windage then something is wrong with the scope and/or your mounts, maybe dovetail not right. You should have the target in the scope and it should be only a couple of clicks to go high with a first shot to hit.

What calibre...??? Why 10 metres...???

[Gwion]

I was just bore sighting it. I always bore sight at about 10m because I can do it from the shed or in this case the kitchen table; I then work my way out with 3 shots each at 25, 50, 100m. Never had an issue before. It's a 7-08.

[Strikey]

I agree with Apollo, bore sighting at 10m is probably at best a waste of time, does the scope's parallax adjust back that close? I bore sight my rimfires at 50m & centre fire rifles at 100m, then with either I fire one shot onto the target and then hold on POA and adjust elevation & windage to put crosshairs onto the bullet hole, usually have rifles sighted within 2-3 shots then its just a matter of fine tuning POI, only rifles I sight in at 10m are my air rifles, bit difficult to bore sight those

[Apollo]

I agree with Apollo, bore sighting at 10m is probably at best a waste of time, does the scope's parallax adjust back that close? I bore sight my rimfires at 50m & centre fire rifles at 100m, then with either I fire one shot onto the target and then hold on POA and adjust elevation & windage to put crosshairs onto the bullet hole, usually have rifles sighted within 2-3 shots then its just a matter of fine tuning POI, only rifles I sight in at 10m are my air rifles, bit difficult to bore sight those

Yep, all that. Too many things can go wrong at very close distance. Perhaps as you have found.

I would not even think about trying to bore sight in my lounge room and down the hallway say 20 metres. Other than set a scope to a verticle reticle line.

[brett1868]

Here's a thought, is it possible to swap the rings front to rear? Curious if windage goes the opposite direction which would indicate a problem with the rings. When you screwed the picatinny rail onto the rifle how were the screws tightened? I generally do the front and rear a bit loose then gradually tighten them while wiggling the rail a little side to side to make sure the screws are centred in their holes. Once torqued down I do the others, using Loctite 222 on all of them.
On the rifles with a round receiver I've placed wet n dry 800 then 1200 rough side up on the receiver then rubbed the bases in to improve surface contact. Might be the base is out or possibly even the screw holes in the receiver. Hopefully just some crap in the notch of the rings.

[Gwion]

Thanks for those tips, Brett. I'll reinstall the rail and double check the other things.

Pretty sure it's not an error with the receiver screw holes because my previous one piece scope mount (DNZ GameReaper) was dead on with only about 2 clicks need to bore sight it at mechanical zero. I'll pull the rail off and make sure it goes back on as well as i can get it and not just drop it on and screw it down tight.

As for bore sighting at close range, i can't see how it could possibly be the cause of such a significant wind out. A point to center on is a point to center on. As per previous post, i have bore sighted like this quite a number of times. It gets me on paper at 25, i shoot a 3 shot group then zero to that, then repeat at 50 & 100m. Sure, i don't expect to hit a target at 100m with a bore sighting at 10m, but to be 16MOA off mechanical zero is just crazy which tells me the problem lies else where. Never the less, i will try again at a longer range after reinstalling the rail.

Might take a couple of goes, changing one thing at a time but hopefully i'll get there with out shelling out for new rings.

[Apollo]

Are we talking about a .22LR here trying to sight in at short range....????

[Gwion]

No

[Apollo]

Sorry, it's a 7-08.

I'll go with the original story. Put the scope back to optical zero, check with it sitting on a mirror to ensure the cross hair sits perfect with the image. Then back on the mounts. If it doesn't line up look at the mounts.

PS..Mechanical Zero does not ensure the scope is "zero"... Center of click range is not perfect. Optical zero is far better. If you don't know what I mean then there are dozens of demo's on UTub.

Windage adjustable mounts are useless. A means of hiding a mechanical fault. It takes a lot of useless mucking around to get windage type mounts to a true center. If the dovetail or picatinny top mount is not aligned with the bore then it should be corrected properly. I suppose it's the quality of the firearm build that dictates.

[pomemax]

Ok I had the same problem some time ago its the rings you using
Mechanically center the scope get a set of windage rings from your lgs dont lap them till you have proven this to yourself
with the scope set on 100 m bore sight it using the rings ONLY
when its ok you know the rest
Talley Tactical are no windage adjustable
http://www.brownells.com/optics-mountin ... 22915.aspx

[Gwion]

Cheers. I'll give it all a go and report back. I've never done the mirror trick but am familiar with the concept and will youtube it to make sure.

If at all possible i'd like to avoid new rings and steer clear of windage adjustable jobbies; they just seem to be one more link that can fail or need maintaining. My best guess is that the rail might need setting properly so i'll start there.

[Chronos]

The advice here is good, because you're trying to zero it at such close range tge erector tube is jammed against the main tube reducing the amount of windage available and cranking it down so hard can damage the springs that control the erector tube location.

Simple as others have said bore sight it at 50-100m in say an A4 piece of paper then fire one round to check POI. Shouldn't take you more than 2-3 rounds to get it very close.

For future referance try sighting it 1.5" high at 10m, you're string to set it near enough to 20moa low at the moment, probably in a scope with 40-50 Moa adjustment.

Chronos

[Gwion]

Hi Chronos. Thanks for explaining the mechanics of how a close bore sighting might cause issues.

The S-Tac has 40MOA windage and 80MOA elevation.

Cheers

[Chronos]

Hi Chronos. Thanks for explaining the mechanics of how a close bore sighting might cause issues.

The S-Tac has 40MOA windage and 80MOA elevation.

Cheers

It's something that's caught me out in the past. As Apollo knows I had a Sughtron 10-50X60 on a 20MOA ken Farrell steel rail that I couldn't get zero'd at 200Y because the elevation was bottomed out and the tube was in the bottom greatly reducing the about of windage adjustment available, the same scope on a EGW 20MOA rail was OK, just a rail height issue I think.

Steve

[Gwion]

Ok, so.

Rail removed and refitted more carefully. Bore sighted at around 80m. 3 rounds fired and corrected for at 50m. Still only 7MOA remaining of right adjustment on the windage.

The elevation is somewhere in the middle with almost 2 full revolutions of the turret to bottom out (15MOA per rev).

If it helps to clarify: it is less a problem of running out of windage and more a problem of being too far from mechanical/true zero. It is something like 13MOA away from true/optical/mechanical zero!

[Apollo]

Something isn't quite right. What breed of rifle is it..??

Another thing I thought of that has been done to check a scope is that when it's all at zero is to rotate the scope when the rings are loose and see if the center of the crosshairs move around the aiming spot. Haven't ever done this myself as I just have not needed to try.

Try a different scope and see if the problem still exists so then rule out the scope. If it's not the scope then picatinny rail not straight maybe and I suppose you have swapped the rings from front to back so that may show the rings are okay.

It's something I have not come across using a number of different picatinny rails and/or rings. Firing test alignment shots are usually pretty close to center on windage under ideal conditions.

I really hope something pops up quick to resolve this problem.

[Apollo]

Another thought I had is about how the picatinny rail is attached to the action. If the action is flat on top or curved, maybe stepped at the rear like a Remington 700. The thinking here is that maybe the screw holes in the action aren't dead straight with the bore line.

If it's a Remington 700 then as I found bedding the rail was a must to get it aligned correctly, especially under the rear.

[Gwion]

It's a Howa action.

I was thinking that the bore may be offline, especially seeing the barrel has just been changed.

Although, i would have expected the gunsmith to take his concentricity off the bore and action centerlines.

This is really starting to worry me and i wish there was a simple explanation. If it's the barrel or the scope, i'm cactus and back to square one. Took 6 weeks to get the scope back. I don't have much spare cash flow and have just spent about $1800 on this project with scope, mounting system and rebarrel.....
I can't keep throwing money at it to fix it.

Not sure how i would correct the misalignment of bore to action centerline!??!

[Gwion]

Try a different scope and see if the problem still exists so then rule out the scope. If it's not the scope then picatinny rail not straight maybe and I suppose you have swapped the rings from front to back so that may show the rings are okay.

I haven't swapped the rings yet.

Maybe i'll try that and then refit the DNZ mount and Vortex scope that were on it when in 223rem. The old scope/mount system worked perfectly, so if that is still good it will rule out the bore alignment as being an issue.

I don't have spare rings to test the Vortex on the rail. Old scope 25mm tube, new on 30mm tube.

[Apollo]

I just had a look at a Howa 1500 that is here, belongs to a Forum member.

Stepped action like a Remington 700 where the rear is lower than the front. Not sure at this stage if it's flat or curved on top. Will have to check later as I'm just heading off to get some supplies. This one has a DMZ one piece base and rings, Vortex Scope. I haven't even checked to see where the scope is set as it all got put away waiting for the owner to return from overseas.

If the gunsmith was asked to true the action then yes it should / would have been checked. The barrel when chambered would be straight and true but is it true to the action centre. The job a gunsmith does here is to true the face of the action so that the alignment is correct when the barrel is tightened up. Some can be a few thou out of true square across the face and this accounts for a lot aiming down range.

It is possibly something you can check but quickly the first thing that comes to mind is to use a "straight edge" sitting along the line of the screws in the top of the action and look down on the alignment with the barrel to see if they are both pointing the same direction. If it is out then just maybe it's something you may be able to correct without a visit to the gunsmith. The thinking here is to have the rail mounting screws loose and see if the alignment can be corrected, then bed the rail to the action with the correct alignment. When epoxy is set then tighten the rail mounting screws. Might be a bit fiddly to get correct but saves on a visit to the doctor.

Just a quick thought.

After thought. Just maybe the mounting holes in the Talley aren't in alignment correctly and something that can be checked.

[Gwion]

Thanks Apollo. I'll check these things out.

I did ask that the action was trued so would expect that was all good.

I'll start by checking the rail/barrel alignment. I'll put the cleaning rod in the barrel to get an idea of where the bore is pointing and align a straight edge to the rail. IF that is out of whack, i'll take the rail off, put the screws in the holes and put the straight edge on them. Hopefully this tells me if its the holes in the action or a fault with the rail.

Cheers.

[Gwion]

Well.. straight edges didn't tell me much.

I remembered i have cheapo rings that i use to mount torches to rails, so have pinched a pair of those and did a rush job of mounting the Vortex Diamondback scope. Bore sighted on same object, same distance. Vortex was about 5MOA off for windage from the old zero, which was very close to mechanical zero. Considering the dodgy cheapo quick release mounts from ebay and the quickly mounted scope still giving me a better result, i am thinking it is either the rings or the scope that is to blame.

Now to do some testing there to see if i can sort it out.

[Apollo]

Rifle clamped in Gun Cleaning Vice. Verticle surface like a door frame aligned in the bore then see where the straight edge points perhaps.

Hope you solve it soon. Things like this can be a real pain.

Reminds me of getting scope reticles perfectly aligned both verticle and horizontal. A lot easier these days with the right equipment and essential for precision shooting.

[Gwion]

Well.

I'm a lot happier now. Swapped the Talley rings front to back, as per earlier suggestion, and now it is bore sighted at mechanical zero!

Probably should have done that first off and can't figure out how it is so much different.

I had lapped the rings when i first set the scope up before the barrel was changed. They must have been swapped from back to front during the whole work process and i believe lapped rings MUST stay in the same configuration after lapping.

Anyway, I'm not going to argue with the outcome or over think it.
I'm just very happy that it all seems to be rectified.

Thanks for the advice and ideas for trouble shooting. Kept me a little bit sane during my mild panic!
Now i can confidently go about the whole load development process.

Thanks again to all.

[Apollo]

Great news, I might celebrate with you and have an early ale.

I had thought about the lapping of the rings, hence the suggestion to swap them around. I would very carefully check the lapping..ie cover all the surface with a texta and make sure the surface is still true. I wonder how much material was removed during lapping. The one's I have done (Kelbly and Ken Farrell) were not even worth doing as the finish wasn't hardly marked but all very even. Well, they are very high quality rings on the same quality pic rails.

Once the check has been done I would as a final task mark each ring section with an alignment mark so they don't get mixed up again...ie one center punch mark on one side at the front and then say two marks on the rear on the same side. The rings I use above are marked during manufacture as matching sets.

Boy, I bet you are happy.

Now you can go enjoy shooting the bloody thing.

The Howa 1500 .223R here is the first I have ever seen or handled and I must say I'm impressed with the accuracy from the hand loads I developed for it. The story of that build is a topic here somewhere.

[Gwion]

Yes mate. Very happy, thanks. I will mark the rings as suggested; i actually told myself to do that when i lapped them and then forgot to!

To be honest, i was very disappointed with the Talley rings. I know they have a good rep, but mine needed quite a bit of lapping to get an even contact surface. I would just have sent them back instead of lapping but as i ordered them online from the States, it makes it a long process. It was quicker to lap them.

Unfortunately the LGS's around here aren't loaded with quality gear and much of what there is has the "Tas Tax" attached. It's often just easier, cheaper and more reliable to order stuff online and put up with the odd inconvenience; especially since it is an hour to the nearest gun shop and i don't go into town all that often so have to make a special trip which adds a lot to the cost of components.

The Howas are a good thing. I'm glad i rebarrelled it instead of forking out for a whole new rifle. In it's 1:12 223rem incarnation, i managed to get it shooting under 0.5moa quite reliably with some attention to loads. Considering i'm far from a great shooter, i think that's pretty bloody good for a cheap rifle. Hope it goes just as well as a 7mm-08.

Cheers again for the help.

[Chronos]

Glad it's sorted Gwion

I've been guilty of marking lapped rings do I know which way they go back on. The sports match rings on my Weatgerby Mkxxii are lapped, couldn't believe how much material needed to be removed from them.



Steve

[Gwion]

I might engrave an F & B across the base and cap of the rings. Anyway, it's not going far in a hurry. After all that, i'm leaving well enough alone for a while. If and when i take the scope out of the rings again, i'll mark them so they don't get mixed up.

Surprisingly, that pic of yours is nothing compared to how out of whack mine were. Oh well... all is good now. Ready to develop some loads and maybe i'll keep up with the other guys at the range a bit better. 50gn 223rem don't really match it at 500+ yards against the 308!

[Strikey]

Well, I am glad we got that sorted but will you have to wait for the snow to thaw before you can throw some lead downrange?