So I finally bought a nice bolt action.  Browning X-bolt hunter in 7mm-08.

Got some Talley scope rings (integrated base) and mounted the lower ring/base per instructions.  Cross pattern, a little dab of blue loctite, not too tight.

Now I'd like to mount the scope but... I'm really kind of at a loss how to do it so the scope is level to the axis of the bore.   I get the concept that some of these instructionals are giving but step 1 is "level the rifle in a vise".

Ok... how do I do that?  There are no flat surfaces on the rifle itself.  I've tried laying a bubble level across the flats of the bottom scope rings but the front one slightly disagrees with the rear one (I've checked with different little bubble levels to make sure I'm getting a consistent reading).  I've tried sticking one of these wheeler magnetic "level-level-level" bubbles in the action, and it appears that the top edge of the plastic is resting on the underside of one of the rails.   And it slightly disagrees with the flats on the scope rings.

The top of the receiver itself is curved.  So no-go there.

The bolt itself has a flat on the top but I don't know if that flat is perpendicular to the bore axis.  Also, it has a little bit of play to it.   So probably no-go there.

Only thing I can think of at the moment would be to scoot the rifle and vise to the edge of the bench, hang a plumb bob off the rear of the rifle and rotate the rifle until the string runs through the middle of the buttstock.  But that has assumptions of its own.

Am I over-thinking this?  This is a pretty popular rifle... surely I'm not the first person to encounter these difficulties?

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Assuming these bubbles are accurate, and I think they are because I bought a pack and got same results with different bubble levels on the same spots, is this about as "level" as I can expect to get the rifle?

Surely there's a better, more reliable method...  I really don't trust this.

Simple method I use doesn't require a level.  Just a vertical line. (I use the pull-up rings on my kid's swing set.)  Mount the scope loosely in the rings so it can be rotated.  Look down the barrel and bisect the bore with the vertical line.  Rotate the rifle so the center of the crosshairs is also on the vertical line while the bore is still bisected by the line. Rotate the scope in the rings so the vertical crosshair agrees with the vertical line.  And you are done after you tighten the mount screws w/o twisting the scope in the rings.  Now the vertical crosshair is aligned with the bore.

I worked at Cabela's for about five years and mounted a few scopes there. I agree with the first post. I used the top of a door frame at the far end of the gun vault.

I can't tell you how many I mounted where there were flats on the receiver for a level and upon shouldering the gun the customer would tell me the scope didn't look level.

D

Thanks, I *think* I get this?   Hm. Tell me if my logic is sound?

Imagining a straight line with three points:

A. Bottom dead center of bore.  B. Top dead center of bore.  C. Middle of crosshair of scope.

When all three are pointed at a vertical plumb line, the rifle is horizontal to earth.  Because we know the plumb line is perpendicular to earth (gravity).

But doesn't this assume that the crosshairs themselves are pointing true in relation to the scope body and not in need of windage/elevation adjustment?

Easiest way is off the flat of the rings with the tops off, problem is holding the rifle flat while you put the scope in the rings and get them close to tight..I use a plumb bob to level my scopes, I also use a couple of digital levels..I can use a rubber band and clamp the level to the side or bottom of my LR rifle which makes it easier...As far as checking a tube level, set it one direction, see exactly where the bubble is, then flip it 180 degree and it should be identical...

This will give you an idea, this is when I changed barrels and used the bipod and bag to set the chassis, then used the digital levels to make sure the action was square in the chassis, and that the rail was level..then leveled the scope with the plumb bob...My chassis also has a built in level, I verified that it is true as well...

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It's hard to see but the DL is rubber banded to the side close to the magazine opening...

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This is using a bright light and a plumb bob against the garage door..Internet pic but I do the same....You don't need the light if the rifle won't move while you look thru it, but the light makes sure you don't touch/move it..

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You do a tall target test(Box test as well) to make sure the reticle moves square up/down as adjusted...I combine them into one test...


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Crud.  Maybe my scope rings/bases themselves aren't bueno?   Or I need reinstall them and more carefully tighten them down?

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Thanks for the info

Can you use the small space where the rail sticks out behind the ring? maybe even move the rings forward as far as you can, install scope, level to the rail, then move the scope and rings back where they go? Or pull the action out of the stock, level off the bottom of the action, install scope and reinstall action?

There's no rail.  They're combination rings/bases that mount directly to 4 threaded holes in the receiver for each ring/base.

I haven't tried taking the rifle apart yet.  Intriguing option, I will keep it in mind.


Watching that tall target test video gave me an idea related to what green canoe was saying.

I did get a little laser bore sighter for this thing.

Theoretically, could I do the tall target test with that?  That is:

Mount the gun in a vise and zero the scope with the laser on the dot at the bottom of the line, then adjust the elevation a bunch on the scope and see if the scope is now pointing at the left or right of the vertical line on the paper.  And if not, loosen the scope ring caps and slightly rotate the scope and repeat until I get it tracking correctly.

My goal here is to be reasonably confident in my windage anywhere between 50 and 350 yards.

I would say so, but you need to pick a distance where you know what the exact distance of 5 mil/moa will correlate from the reticle to the target..you use the same aim point for every shot on the cardboard, most use 100 measured yards to test.....Other wise you are not checking the dials of your scope for consistent accuracy when you dial...

OP,,,A five ft. level hanging perfectly horizontal on string at fifty yards will give you all you need. Sit on a BENCH and rotate the scope in your rings and then GENTLY tighten the mounts until the horizontal reticle is mated left to right. Take the gun off the bench and then tighten to the manufacturers specs IN THE WAY THEY TELL YOU.

Excellent.  I will start with the laser and then confirm with ammo later at a buddy's range.   I was mostly thinking of this test in terms of ensuring scope level but that is some useful info in there for determining your "correction factor" for longer range shooting.  Will be good to know.  Scope is a styrka S6 3-9 power.

Also, since I'm kind of doing a reverse version of the tall target test, I'll need some vertical line on both sides of the dot to help ensure that the scope/rifle is being "aimed" level in case it moves (despite the vise) during adjustment of the elevation turret.

Thanks, but I don't think that would ensure the scope was level to the axis of the bore of the rifle itself, would it?   Maybe I'm just not visualizing it properly.

This is discouraging.  The mounts themselves aren't square, suggesting whoever tapped those holes, didn't tap the front pair aligned with the rear pair.  Meaning there's going to be a weird torque on your scope before you even get started, because the "shaft" inside the ring bodies, and their alignment, are already off.

As to "level", TBH, I've found just eyeballing it can work.  As someone else suggested, just pulling your head-back and eyeballing if the vertical part of the reticle is in-line with the rifle, works well enough.  

If that's not what you were wanting, I think if you pop off the magazine floor-plate, you'll then have a square section with the magazines walls, that you can rest the gun on a surface, to use.  That's essentially how I do with an AR, is rest it on the mag-well, put it on a table-top with the stock off, and the forward upper extended off the table, so all the weight is resting on the square mag-well, which is level.  Then put a bubble on the top rail, and note how much it's off plum, and that's my actual plumb.  Then mount the scope, put the dial cap screwed down, so that it's a flat surface, and put the bubble on top of that.  Match it to whatever plumb I saw a moment ago resting it on the bare rail.  

Yeah, its not exactly thrilling to me, either.

I'm tempted to pull them off and try putting them back on again and use a bubble level to check across the flats as I tighten the screws down to see if that has any effect.

I followed the directions and screwed them down in a cross pattern (4 screws per base) in a cross pattern.    But maybe I screwed it up nevertheless.

Before you do that, flip both of the bubble levels 180 degrees and see if they read the same..ideally you only want to use one level, always kept in the same basic position for all leveling, unless you know they are all accurate..

I did.  A couple of those cheapie levels don't track but a couple of them did.

Going with the ones that repeat when flipped, it looks like when the rear scope base agrees with the wheeler magnetic thingy in the action, the front was about 1/3 of a bubble off.

I took the front ring/base off and there was a little bit of dried loctite debris on/under it.  I cleaned that off and put it back on (without loctite) and checked it again and it looks like it helped a bit.   So maybe that was part of the issue there.  Its interesting that even after that its still off in the same direction, even if not as bad.

Using the same (known good) little bubble level each time:

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That does look much better, if you just set a scope on there now, does it sit down tight with no gaps in both rings? If not then you have more to do..that is one advantage to a rail and a single mount, much harder for stuff to not fit right...Plus they do make rails now with a built in level...

I didn't have a digital angle finder so, good excuse.

Agrees with the bubbles, more or less.

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Will mount the scope next and see if I can get a feeler gauge in there.

Then I'll try the kind of "reverse tall target" with the laser and see what I can see.

My best guess, the scope is going to be angled a little side to side versus if that ring was level, it has to be because the angle it sits at compared to the rear ring is going to be tilted just slightly left..just another thing to know and be prepared for... Thats weird its off that much, I am sure it happens, I just have never seen it.. I know Bartlein barrels wanted to know when they trued my action during barrel install, if I wanted the rail replaced with one with bigger screws(#8's), they said it allowed them to make sure the holes were properly located if they were off...But he did say mine were on regardless and the bigger screws were just to insure they stayed tight better than the stock #6's......That might be what you have to do to get the scope to fit properly...

This,
It removes relying on any flat surface on the rifle which may/may not be perpendicular and align the scope centerline with the bore.

Similar.  I use the shop door. Then the edge of the house. Any vertical or horizontal surface.

Does anyone think there will be a ring to ring alignment issue? Or the rings will need to be lapped?
Does this type of misalignment cause scope issues, at least marking the scope or bending the scope tube?

Good question.

I would guess any misalignment bad enough to physically damage the scope would look or feel pretty obvious when I go to tighten the scope down.   But I don't know that.

I've learned the hard way that scopes are tough / scopes are fragile.  Having just a little too much torque on my scope rings, and we're only talking by a handful of inch pounds, bound up one of my scopes adjustments so bad I was angry at having a bad scope, and called them.  They said to "loosen the torque on your ring, it's overdone" - which was super lame since I already torque wrenched it with care to about what it said (you know, with just a touch more, of course).  So whatever, I loosened it to show them that clearly wasn't it... annndddd the scope worked just fine thereafter.

Point being, I really don't know if those misaligned rings will be a problem at all , or not.  The more torque you put on them, the more stable it'll be I suppose, but if you put too much torque on your rings, Well, I've seen weird things happen.

TBH, I'd be tempted to get a set of 30mm rings with the 1" plastic inserts, and run a 1" scope in that, to see if that will give you a little more play balancing with the off-set rings maybe.  I just made that up, so maybe someone with more experience has another thought.

I would take it to a good smith and have him fix the holes, even if it meant going to a rail with larger screws and either rings or a mount... I prefer a mount just because it pretty much ends ring issues and damaged scopes for good....Or if I have to have mounted rings, go back to the manufacturer and see if they will replace the action with a straight one...

I'm still not convinced there is a problem.  The rings are mounted on a curved surface.  The bolt holes have clearance so the bolts can go in w/o interference.  I think one of the bases is slid around the curve compared to the other.  In this case I'd use a bar the size of the scope diameter, lock one ring onto it, and then mount that assembly to the top of the rifle.  Now mount the other base to the rifle using the bar to guide it into the correct location. Now the rings will be aligned when the scope is dropped in.

ETA: Your logic is sound.

Actually, the level method assumes the crosshairs are perpendicular to some mechanical feature on the scope body. And it should be if you have a quality scope.  But do you know for sure? The method I use doesn't care about the mechanical relationship between the crosshairs and a flat on the scope body.  Now you could end up with tracking issues theoretically this way, (i.e. The crosshairs don't line up with the direction of the adjustment movement.) but the few scopes I've mounted intending to dial range and windage have worked out fine when doing the box test.  (My hunting rifles are set and forget at MPBR.)

There is too much error between all the bubble levels and thinking you have surfaces that are machined perfectly level with the ground to begin with.  You have to find a way to get the gun oriented as vertically as possible, whether it's eye-balling it or using a SINGLE digital level or bubble level somewhere on just one part of the gun.  I like to use a locking bipod so I can adjust to what I think is perfectly vertical.  In the case of my SCAR receiver, for example, I just use a Klein digital level and set it on the top picatinny rail until I'm reading 0 i.e. level.  Then, I lock the bipod and look through the scope at a building or some structure that is pretty far away.  Find a corner of the building and align the vertical crosshair in the reticle to the vertical corner edge of the building.  Done.  Some others in this thread also alluded to using this method, but that's exactly how I do it.

For a gun that doesn't have a flat spot to rest a level on it, you are probably going to have to decide whether you trust a clamp/vise/shooting rest or your eye and/or feel when shouldered on a locking bipod or tripod to decide which method is more accurate for getting the gun oriented vertically.  I don't see any other way to get a better reference position to start from.  If anyone has any interesting methods, I'd love to learn what y'all are doing.

This is the method I use, except I have a dedicated plumb bob hung in my back yard

Sig had a genius idea, they put a leveling line on the scope tube.

Meh.  At long range, might not translate.  Best to zoom in on a building that's far away and use the edge of it to align with the vertical crosshair.  Then, you know you're aligned even at that further distance.  Leave it to Sig to use more gimmicks to fool people into thinking they make quality products.

Definitely. I never trust anything but the reticle when it comes to scope leveling.