Scope mounting.

[williaada]

Wanted to get peoples opinion on this: I have a 7mm-08 feather weight model 70 Winchester, and I can get the gun would hold great groups with premium bullets, but throw cup and core bullets all over the place. Plus, the Point of Impact seemed to change. This evening I pulled the scope and mounts off the rifle. The mounts are Talley Rings. I found out the rear ring is a touch taller than the front ring. Has anyone ever done this before? Is it another way of trying to get something similiar to a 20moa on the rings using these rings. Would this explain my point of impact has not been very consistent? Attached a picture of the bases the rear one was higher

 

[p_ham]

The front and rear bridge on the receiver aren't on the same plane. The rings have to be different heights.
Featherweights can be finicky just by nature. Also double check to make sure the barrel is actually floated. Had one in not too long ago that I had to relieve part of the barrel channel and recut some of the action inletting. The stock was pushing the barrel so hard on one side of the shank you could see the forend flex when you tightened the action screws.

 

[williaada]

Thank you for this I have been going back and forth checking this.

 

[OntarioHunter]

If the barrel is floating properly, then you may need the opposite treatment. For whatever reason no one knows, some barrels shoot better with a pressure point. It's not common but does occur. Loosen the action, slide a doubled over business card between the barrel and fore end about an inch down from muzzle end of fore end. Tighten it up and see how it shoots that way. If an improvement then you can try to install a pressure point yourself from internet instructions or have a gunsmith do it. Shouldn't be expensive.

 

[OntarioHunter]

I would suggest checking to see if the rings need to be lapped. Gunsmith can do it or you can order/borrow the tool. It's simply two inch diameter short solid rods ground to a fine tipped cone on one end. Clamp them in the rings with cone tips just barely touching. If the tips don't line up after rings are torqued, then you may need to have the rings lapped. This could be caused by a lack of uniformity when the rifle receiver was machined. I believe you can buy the lapping tool but probably better to have a gunsmith do it. If the rings are badly out of alignment they will need to be shimmed. That might be a job for a gunsmith.

My WWII Springfield required significant shimming under the forward scope base (now front of rail). Three different plants were producing these military rifles at warp speed during the war. Looking at them in military configuration, it's easy to tell there would likely be slight irregularities in external cosmetic machining. Just not important at the time on a gun designed primarily for iron sights.

 

[williaada]

Thanks everyone for the suggestion. I remounted the rings and checked the rings with the lapping pins and everything lined up correctly. I did check the free float of the barrel and it is tight getting a dollar bill between the stock and barrel.

I might mount the scope and shoot a few groups at the range. If the groups do not improve. I will take it to a gun smith to try and figure out the issue.

 

[OntarioHunter]

Thanks everyone for the suggestion. I remounted the rings and checked the rings with the lapping pins and everything lined up correctly. I did check the free float of the barrel and it is tight getting a dollar bill between the stock and barrel.

I might mount the scope and shoot a few groups at the range. If the groups do not improve. I will take it to a gun smith to try and figure out the issue.

Try the business card pressure point. Take a screwdriver to the range and remove the pressure point if no improvement. Then try again. I have a feeling pressure point may be the solution. Thin lightweight barrels can be wiggly and produce inconsistent harmonics especially when changing bullet weights.

Hmmm. Might want to first open the barrel channel just a bit if dollar bill is tight. Wiggly lightweight barrel may be making contact inconsistently. It won't hurt anything to open it up a bit more.

 

[oxn939]

I would suggest checking to see if the rings need to be lapped. If the tips don't line up after rings are torqued, then you may need to have the rings lapped.

Of all the rifles I've checked, I'd say almost half had some degree of misalignment. Of that, I only correct the smallest misalignments by lapping- generally, it's a new set of rings and/or bases until the points of the lapping dies get close enough that you really have to look at them a while to tell if there is any anomaly.

If the groups do not improve. I will take it to a gun smith to try and figure out the issue.

Before taking it to a smith, make sure 100% of the points where metal touches metal between your scope, rings bases and receiver are degreased, cleaned and then torqued correctly with blue Loctite. Frequently, especially with lighter 1" body scopes, over-torquing the ring screws can compress the erector tube and cause consistency issues.

 

[Blaing]

Hi there, I am looking for some suggestions or advice on mounting a Nikon P5 4-16 x 42 on a new Sako 85L that I am having issues with.

Here is the situation:

Rings are Low Optilocks (2 piece) with long (not extended) bases. The scope I am trying to mount is a Nikon P5 4-16X42 and is new.

I am mounting using a wheeler level system and a Bushnell arbor style boresighter. When I mount the P5 scope I do not have enough windage in the scope to boresight in the left direction. I have changed rings from Low to Xtra Low and have used a laser sight as well am significantly off in windage.

I have taken the scope off - re-zeroed the windage and re-mounted it on a Tikka m695 in 7mm RM. It is only 4-6 clicks off the center of the boresighter when it is leveled and mounted. I have now done this about 6x with the same result. The laser bore alignment tool is also on point and verifies very close alignment.

I have taken an older Bushnell 3200 and Nikon Prostaff 1 with a 3-9 x 40 and mounted them on the Sako with the same rings and plastic inserts. The boresighter is no-more than 6-8 clicks off of centre with windage once leveled. The laser bore alignment tool also verifies very close alignment. I have also reproduced this at least 5x with each of these scopes.

When I reinstall the new Nikon p5 back onto the Sako..using the same plastic inserts and rings I keep having the same windage issues. I have lost count of the times I have tried this.

Does anyone have any insight? I am nervous to purchase a new scope that may have these same issues when I go to mount.

Thank you

 

[OntarioHunter]

Borrow or buy another set of rings. Try that. Then try changing the bases. It is possible the receiver was not tapped properly (but that would be surprising considering Sako's reputation). It is always possible to shim the base to compensate. I had to shim the front end of the rail I put on my Springfield because the dovetail for old military rear sight was a little high. This can be fixed. But first you need to make sure exactly where the problem lays. Sounds like it may be the scope but you need to know for certain.

 

[Blaing]

Borrow or buy another set of rings. Try that. Then try changing the bases. It is possible the receiver was not tapped properly (but that would be surprising considering Sako's reputation). It is always possible to shim the base to compensate. I had to shim the front end of the rail I put on my Springfield because the dovetail for old military rear sight was a little high. This can be fixed. But first you need to make sure exactly where the problem lays. Sounds like it may be the scope but you need to know for certain.

it could potentially be the bases. The Sako 85 has a dovetail receiver and is not tapped so there are a few types of rings/bases that work. I have changed the rings from Xtra Low to Low and back.

I assumed it was the scope, but I did mount the problem scope onto a Tikka without any of the windage alignment issues.

Any other thoughts?

 

[3855WIN]

Thanks everyone for the suggestion. I remounted the rings and checked the rings with the lapping pins and everything lined up correctly. I did check the free float of the barrel and it is tight getting a dollar bill between the stock and barrel.

I might mount the scope and shoot a few groups at the range. If the groups do not improve. I will take it to a gun smith to try and figure out the issue.

You get great groups with premium bullets. Case closed. Shoot them.

 

[OntarioHunter]

it could potentially be the bases. The Sako 85 has a dovetail receiver and is not tapped so there are a few types of rings/bases that work. I have changed the rings from Xtra Low to Low and back.

I assumed it was the scope, but I did mount the problem scope onto a Tikka without any of the windage alignment issues.

Any other thoughts?

Check the scope rings alignment. Wheeler sells a kit. Or any gunsmith should be able to do this. If the rings don't line up, consider adding a rail.

 

[dandredeshon]

Wanted to get peoples opinion on this: I have a 7mm-08 feather weight model 70 Winchester, and I can get the gun would hold great groups with premium bullets, but throw cup and core bullets all over the place. Plus, the Point of Impact seemed to change. This evening I pulled the scope and mounts off the rifle. The mounts are Talley Rings. I found out the rear ring is a touch taller than the front ring. Has anyone ever done this before? Is it another way of trying to get something similiar to a 20moa on the rings using these rings. Would this explain my point of impact has not been very consistent? Attached a picture of the bases the rear one was higher

.

 

[Hilljackoutlaw]

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[cahunter805]

it could potentially be the bases. The Sako 85 has a dovetail receiver and is not tapped so there are a few types of rings/bases that work. I have changed the rings from Xtra Low to Low and back.

I assumed it was the scope, but I did mount the problem scope onto a Tikka without any of the windage alignment issues.

Any other thoughts?

If I’m understanding You installed 2 other scopes on the Sako and they both were good with windage with the current bases/rings.
I would assume the P5 has a bent/out of round scope tube or something internal isn’t correct even though it did work on the tikka.

Are you leveling off the scope turret? Some are not very square to the scope/reticle.

 

[Blaing]

If I’m understanding You installed 2 other scopes on the Sako and they both were good with windage with the current bases/rings.
I would assume the P5 has a bent/out of round scope tube or something internal isn’t correct even though it did work on the tikka.

Are you leveling off the scope turret? Some are not very square to the scope/reticle.

Thanks Cahunter - you are correct. I am levelling off of the turret, but the inconsistency there should be also noted on the tikka I have test mounted to. I did notice the rings are farther apart by about 3/4 of an inch on the Tikka. I wonder - could the ring location (being closer together) on the sako perhaps be putting pressure on the tube in a different place, push it out of alignment if the internals or tube were not true?

 

[Kevin11mee]

So, you're getting good groups with premium bullets and when you switch to cheaper bullets the groups open up and there is a different point of impact??

 

[cahunter805]

Thanks Cahunter - you are correct. I am levelling off of the turret, but the inconsistency there should be also noted on the tikka I have test mounted to. I did notice the rings are farther apart by about 3/4 of an inch on the Tikka. I wonder - could the ring location (being closer together) on the sako perhaps be putting pressure on the tube in a different place, push it out of alignment if the internals or tube were not true?

If the scope tube is bent/out of round this would explain why it works on the tikka in a different location.
Nikon scopes are IMO not the best quality and it could very well be any number of issues with it. They are also out of the optics business now.
If it were my rifle I would purchase a new scope and mount it and see what happens. I would also call Nikon and see what they would do for you.

 

[Wind Gypsy]

Thanks Cahunter - you are correct. I am levelling off of the turret, but the inconsistency there should be also noted on the tikka I have test mounted to. I did notice the rings are farther apart by about 3/4 of an inch on the Tikka. I wonder - could the ring location (being closer together) on the sako perhaps be putting pressure on the tube in a different place, push it out of alignment if the internals or tube were not true?

It’s possible. Try it without the ring caps torqued down.

Id pull the bolt and try bore sighting with your eye through the bore rather than the laser before buying anything else.