Moving scopes between guns, rails

[jrock]

I've been slowly moving my sporter rifles bases over to EGW rails so I can move my nice Zeiss scope back and forth between guns. Yesterday was my first test. I found that on one rifle, the scope's horizontal adjustment was near zero. Then moving to another rifle, it was off by 2' at 100 yards. I swapped the rings front to back and back to front (TPS rings) which brought it down to needing 8" more of horizontal adjustment than available. I plan to spin the rings around so the base ring nut is on the other side of the rifle and try again. However, I 'm not sure this will work but even if it does on one rifle, it will be significantly off on the other rifle. I don't want to lap the rings on one gun as I'm afraid it will make the zero worse on the other. Any suggestions?
It also seems that if I move the scope between guns, the level between the scope and the rifle will be different for each gun. Seems like this plan isn't so much modular but requires lots of sighting in every move.

 

[dsculley]

Get some Burris Signature rings with the inserts. Test and see which two rifles are the most different and adjust the rings to be in the middle of those two. Pick one rifle as your primary, zero the turrets then test the other rifles, recording the adjustment necessary from your zero position. You can now change from one to the other and know how to adjust to put that rifle back on "zero".

 

[jrock]

It looks like the Burris XRT rings for a rail are about $90. My gunsmith says he'll re-drill the holes for $100 bucks which seems steep to me. How about shimming the rail or milling it down? If I have to dump $100 into the gun, I'd rather have machining done to make it all straight than use rings which would have to be adjusted every move. However, they may need to be re-leveled and thereby adjusted between guns anyways....??

 

[Laelkhunter]

Not sure if it is possible to move one scope between two rifles and not make adjustments for the final zero. I would recommend getting a bore sighter (with the grid) such as Tasco or Bushnell, or a better one. When you have the scope sighted in on one rifle, install the bore sighter and record where the scope crosshairs are on the grid. When you move the scope to another rifle, sight it in, then record where the crosshairs are now on the grid. When you put the scope back on the first rifle, you can align the crosshairs to where your notes tell you it was before you removed it from the rifle. It should be close.

 

[jrock]

Not sure if it is possible to move one scope between two rifles and not make adjustments for the final zero.

I'm not looking for a dead on zero from gun to gun. Just within reason as I re-sight in all my guns before hunting season. I moved the scope to a custom action and it was within 3 clicks either way from my first gun which makes me think the 2' off is being caused by something more than just rings and rails.

 

[Laelkhunter]

Might be something more. I just suggested using the bore sighter as a means to save some ammo, and to get you close. I use the bore sighter when I transport my rifle to my Elk hunt. I check the grid with it before I leave, and then again when I get up there. It never seems to be off any, and when I shoot it, it is still zeroed. Good Luck !!

 

[jrock]

Last night I investigated the potential issue. I checked the level on the first gun and it was close. Bore sighting at 60 yards, the cross hairs were 5 inches to the right.

However, when checking level on the other gun, I discovered that the receiver was not milled parallel to the race ways. Cross hairs were 6" to the left when bore sighted. Seems like this I the problem. Seems like I need to shim up one side of the rail to make it level but I don't think that would bring the cross hairs in more. Any thoughts before I try epoxy bedding the rail with shim stock?

 

[Georgiashooter]

Unless the barrel shoulder and receiver face on that Remington have been squared, that is likely the horizontal issue. Could be in the savage as we'll.

 

[jrock]

Unless the barrel shoulder and receiver face on that Remington have been squared, that is likely the horizontal issue. Could be in the savage as we'll.

The Remington is stock but the Savage has been trued and rebarreled. I'm thinking of dropping the scope on my Defiance action as I know that rail should be straight and lapping the rings. However, with TPS rings, I feel I shouldn't need to lap. I have an email conversation with EGW about it and they are implying I'll need to shim and bed the rail.

 

[Georgiashooter]

I've had two egw rails that exhibited these problems. One on a model 70 one on a 700. Scrapped both and went with leupold Mark 4. I've since used several Talley rails that fit as well as leupold. If I build a rifle and assemble everything to the best of my ability, including a new scope, I seldom need to make more than 1 moa windage adjustment when bore sighting. I've mounted new scopes on factory rifles and remember some needing as much as 7-8 moa. It's a wonder they'll shoot as well as they do sometimes. If you have access to another rail, try it and see if it fits any better. Good luck

 

[jrock]

I played around with it more tonight and noticed when I leveled the raceway at the ejection port the whole gun looked crooked. I leveled the gun via the stock and how the back of the action looked by eye and put a level on the tang raceway. By golly, it was dang level. Checked the the top of the receiver and it was level too. Put the rail on and level. Guess the raceway surfaces on the ejection port isn't necessarily the surface to be going from. Still didn't fix the horizontal adjustment.

Georgiashooter, now it makes me think the rail or screw line isn't right. I don't have another rail to try. I decided to bed leaving the front screw and back screw loose and twist the rail more toward center and hold in place while the kwik JB set up. Testing the idea before bedding seemed to get me back into adjustment range but not perfect. We'll see if it took tomorrow and maybe run a shooting test this weekend. If that doesn't work, I'll order a Nightforce or something and see if that is any better.

Thanks for all the ideas

 

[LoneTraveler]

It seems to be the nature of the beast, Barrel and action not in line, Screw holes in rail or in action out of line. Measurements of the rail itself.
I have been trading scopes for over 50 years and have ran into that many times. My suggestion would be a laser that fits in the chamber like a shell would be the easiest solution to getting close. Quicker and less ammunition.
The only setup I have ever seen you can change one scope from one rifle to another and be zeroed in on each rifle is the old Baush and Lomb system that the actual adjustment was in the mounts themselves. Not in the scope itself. Good Luck on this project.

 

[jrock]

It seems to be the nature of the beast, Barrel and action not in line, Screw holes in rail or in action out of line. Measurements of the rail itself.
I have been trading scopes for over 50 years and have ran into that many times. My suggestion would be a laser that fits in the chamber like a shell would be the easiest solution to getting close. Quicker and less ammunition.
The only setup I have ever seen you can change one scope from one rifle to another and be zeroed in on each rifle is the old Baush and Lomb system that the actual adjustment was in the mounts themselves. Not in the scope itself. Good Luck on this project.

This is what I was afraid of. Well, it was worth a shot. I ended up bedding the rail while holding it in a new alignment. It got it on paper and it's functional and super accurate. I did have to adjust the level on the scope about 3/4 of a bubble to get vertical tracking in line. I was thinking of those laser cartridge bore sighters as well. I'll just have to hold for wind which it seems I'm migrating too anyways.