Scope reattached consistency

N454casull

Awhile back I took a scope off of a gun in anticipation of using it on a different gun. I ended up getting a new scope for said gun and am going to mount the scope back on the original gun. 

My question is how well will it “return to zero” when mounted? Nothing has been adjusted I never removed it from the rings, never took the base off the gun. I think it should be pretty close but will need some fine tuning. Anyone ever try this before? 

Zee

Depends on the quality of the rings and the base they are attached to. Not to mention the consistency of torque/reattachment. 

Zee

I have torqued down quality rings to quality bases, removed them, and reattached with the same torque to have minimal (sub-MOA) shift. But, I wouldn’t bet my career on that consistency (depending on the shot distance). I would always confirm if given the opportunity. 

Linefinder

What Zee said.

Mike

N454casull

Zee said:

I have torqued down quality rings to quality bases, removed them, and reattached with the same torque to have minimal (sub-MOA) shift. But, I wouldn’t bet my career on that consistency (depending on the shot distance). I would always confirm if given the opportunity. 

I plan to confirm 100% I’m just curious how close it will be. Do I need to get out the giant cardboard target or will a standard target do. In my mind it should be close but will definitely need some adjustment to get back to zero. 

CHIRO1989

N454casull said:

Zee said:

I have torqued down quality rings to quality bases, removed them, and reattached with the same torque to have minimal (sub-MOA) shift. But, I wouldn’t bet my career on that consistency (depending on the shot distance). I would always confirm if given the opportunity. 

I plan to confirm 100% I’m just curious how close it will be. Do I need to get out the giant cardboard target or will a standard target do. In my mind it should be close but will definitely need some adjustment to get back to zero. 

Science! Maybe start at 50 with the big target, I just staple 4 Shoot-n-See edge to edge and aim for the middle and go from there.

Big Al1

I always check a scopes zero with a bore sighter before I take it off. Record the grid coordinace and then check it again when I reinstall and adjust as required, then confirm by sighting it in!

Zee

N454casull said:

Zee said:

I have torqued down quality rings to quality bases, removed them, and reattached with the same torque to have minimal (sub-MOA) shift. But, I wouldn’t bet my career on that consistency (depending on the shot distance). I would always confirm if given the opportunity. 

I plan to confirm 100% I’m just curious how close it will be. Do I need to get out the giant cardboard target or will a standard target do. In my mind it should be close but will definitely need some adjustment to get back to zero. 

What scope/rings/base are you using?

Thats the deciding factor. 

Zee

For example, any of the modern cross bolt rings like:
Leupold

Burris

Spuhr 

Vortex

Should work. Always remember though, trust but verify. 

I would not trust a vertically split ring like Warne. 

Windage rings

And I’ve not had good luck with LaRue rings. 

Diver43

Kind of like the TV shows. Sniper takes gun parts out of a case, screws in barrel, connects scope and loads a huge looking bullet and makes a shot half a mile away.  I used to believe that's how it worked.  Now I know its bore sight then site in before using the gun.

N454casull

Zee said:

N454casull said:

Zee said:

I have torqued down quality rings to quality bases, removed them, and reattached with the same torque to have minimal (sub-MOA) shift. But, I wouldn’t bet my career on that consistency (depending on the shot distance). I would always confirm if given the opportunity. 

I plan to confirm 100% I’m just curious how close it will be. Do I need to get out the giant cardboard target or will a standard target do. In my mind it should be close but will definitely need some adjustment to get back to zero. 

What scope/rings/base are you using?

Thats the deciding factor. 

Burris XTR-312

Warne one piece rings (not the split top style)

Standard Picatinny rail milled into receiver. 

Zee

I googled the rings and they show 3 different styles. But, the ones I saw should all work as long as the torque settings are the same as when you took the rings off and possibly even torqued in the same order. 

In theory. 😁

N454casull

Bigslug

N454casull said:

The general key to the cross-slot family is to make sure you get the mount back into the same slots they came out of, push them forward in those slots as you start to snug the bolts down, and go to the same torque you started with.  Even so, expect gremlins and be happy if they don't show.

But sometimes you get lucky.  Before I sent a Leupold back for a CDS dial upgrade, I pencil-marked the ring location on the tube before I pulled it off the MK4 base/ring combo (the base and ring bottoms stayed in place).  When the scope came back, Leupold had set the dial in the 100 yard location for my load.  Re-mounted in the rings and the first shot pinwheeled the target paster.  I am still GREATLY puzzled where I managed to accumulate that kind of positive Karma.

Justsomedude

I think people should also lap their rings in with a lapping rod. Most people would cringe to see just how "straight" the clamping force is.

Gene L

I wouldn't think it would be consistent.  Military sniper rifles, which can have the scopes dismounted and remounted and return to zero have a LOT of engineering to make this happen. If it does return to zero on the OP rifle, it's just chance.

What you might try is firing a round with the original scope/rifle, then mount the new system and track the scope on the bullet hole...and I don't know if that would work, either.

ilove22s

fwiw,

i think it will depend on how everything worked together in the first place.

You have no idea if something didnt fit correctly and was just more or less hammered/tighten into place. 

Then the mechanical side in me says you have X, Y and Z to deal with and then the quality of the scope and how collinear the tubes are in front and back of the turret the mounts too.

I know im probably make it a bigger deal than it is, but in reality you wont know until you do it and if it was me, i sure would not bet my life or maybe some game on it.  i would VERIFY after you get things put back together.

N454casull

I haven’t had a chance to try it out yet scope is remounted in the same spot it was before. Weather has just been crappy the last couple of days. As soon as I get a chance I will post the results. 

N454casull

knitepoet said:

Okay, I just took 2 to the range to re-confirm zeroes.
1) Home built 300BO upper, P Series mount.  Just remounted it after removing my NV. Required 1" up 1/2" left with the same ammo it was zeroed with previously

2) Alexander Arms Overwatch 6.5 Grendel upper, 24" Shilen barrel. Barrel had been removed and threaded also. GG&G riser with Burris Signature ZEE rings that were NOT removed from the riser. 3" low and 1/2" right

I suspect on the Grendel, removing and re-installing the barrel had as much, if not more, to do with the shift of POI as removing and replacing the scope and riser

I had some family stuff come up and still haven’t made it out. 

But this is about what I was thinking it would be. Not drastically off but definitely needs some adjustment.