My scope mounting routine

[Altitude sickness]

I mounted a scope on my newly acquired Dakota 76 in .338 WM today. I’ll go thru my steps and maybe someone can give me an easier, better way to achieve a quality mount. Or perhaps someone can use some tips.

Without going to a Pic rail there are limited options for the Dakota 76 . Talley and Leupold. I bought Talley bases and rings.

My first step is to completely remove the oil from the bases, rings threads and bolts. Most manufacturers Torque specs are for dry components not oiled.

They are shipped with a protective film of oil. So I use brake cleaner to remove the oil from all surfaces. It also removes any remaining minuscule shavings left over.

 

[Altitude sickness]

Unfortunately for most African style hunting rifles one piece mounts and Picatinny rails are verboten. So we use 2 piece mounts. Which are prone to alignment defects.

from Murphy rail manufacturing. https://www.murphyprecision.com/scope-bases/dakota-arms/
“Most modern rifle actions are machined to fairly close tolerances, but before the common use of CNC machining equipment, tolerances were much looser. In addition to any errors in the original machining, most rifle actions are polished afterward to remove any tooling marks. While this leaves a pleasing finish, most freehand grinding and buffing can lead to errors of several thousandths of an inch in critical areas. Without bedding, the only solution is to tighten the scope base screws enough to warp the scope base and rifle action sufficiently to make close contact. This warpage can lead to a host of accuracy robbing problems in both your rifle action, and scope.”

So after a thorough cleaning I install the bases and rings then check them with my slide alignment tool.

https://www.amazon.com/Scope-Ring-Alignment-1/dp/B0BV161PF3/ref=mp_s_a_1_8?crid=YU7ROCMYAEXS&dib=eyJ2IjoiMSJ9.Y6wBAnKUmCuKcghHdq62SpMWXMKs5iieOZAsaTeuW7OgrhxIM0ecrUYypb-kI6LOZG7A5aJM7PjuzX87d_nQNwsPk_Sojx8WsbLIdQ_RNVJXpFdYvAiV6fMnikuSLV_0Gm6lWTMtF7Nv3sDCXqcLCBgGy_8lW4ivmPONwVV7x5k4EgkoPY7nvNtxuAqqN5Jj2YYcjwFOfpXQ7vuz0FZsOA.Xr2dMVfHCzZRjQSh8BfqO0atXc2hnydVyfa2P8tUMwk&dib_tag=se&keywords=rifle%2Bscope%2Balignment%2Btool&qid=1785887883&sprefix=rifle%2Bscope%2Bal%2Caps%2C214&sr=8-8&th=1&psc=1

 

[Altitude sickness]

Most hunters do not go to the extremes as the extreme long range guys do. Benchrest and the 1000 yard to 2 mile guys must perform these mundane tasks.

Also the owners of expensive optics that want their scopes operational and defect free.

Unfortunately my slide alignment tool showed a slight bind from the Talley rings. If I was using a more robust scope tube like
Nightforce Atacr, S&B or Tangent Theta I would have called it good. But I was mounting a 1” tube Swarovski so needed more precise alignment to eliminate 100% of any bind or high spot contact points.

 

[Altitude sickness]

So out come the dreaded lapping rings. I should move my earlier oil stripping step to after the alignment step. Because now I’m about to get a greasy gritty mess all over the items I just cleaned.

(Rings bolts partially removed) I was loosening and removing the bar then remembered to snap a pic before removing the bar.

 

[Altitude sickness]

After lapping, everything had to go through an even more rigorous cleaning to ensure no grease or grit remains. Then try the slide alignment again. This time with a lite flick of the finger the sliding ring easily glides back and forth showing 100% alignment with zero bind. And the lapping also removes the high spots . Which left in would have been the only contact points between the rings and scope.

This puts uneven pressure on a tube and drastically reduces the holding power of the rings

If you look, you can see where the lapping compound removed the high spots giving perfect alignment and perfect contact.

 

[Altitude sickness]

Next, I bring out the scope level kit and bore sighting tool. And now I have one happy scope sitting on a beautiful Dakota rifle. Waiting eagerly to be shot.

 

[Altitude sickness]

It would be much easier to slap a high quality one piece base and rings on or a Pic rail.

Also to get 100% perfect bases and rings the price of those brands are double and triple the cost of Talley. And are not available in all rifle brands.

 

[Tex .416]

It would be much easier to slap a high quality one piece base and rings on or a Pic rail.

Also to get 100% perfect bases and rings the price of those brands are double and triple the cost of Talley. And are not available in all rifle brands.

This all day long!!!!

Using vertically split rings is the root of the trouble. Lapping does not fix the problem. It is a poor design. Why they continue to exist is hard to understand. They are only one step less bad than windage adjustable bases, which are absolute garbage.

There was a good study done 15 - 20 years ago, which I cannot find right now, which compared different styles of rings for uniformity/deformity. Vertically split rings can be manufactured to essentially perfect tolerances. However, mounting them is the beginning of the problem as they cannot be tightened evenly like rings with horizontal seams and caps that are tightened down separately from the cross bolt pressure. Vertically split rings are very challenging to mount with even pressure due to the design and result in uneven pressure on the scope tube. That leads to the erector binding and ultimately increases the likelihood of failure. Lapping does not fix the problem. Every time they are loosened and retightened, they may or may not come back to the same alignment. Hitting the side of a buffalo or elephant probably will not matter, but if they are loosened, the scope is bumped while the vertical rings are loosened risks things changing. I know 20 guys will chime in they use them all they time and never had a problem. Great, awesome, happy for you. They still are a poor design that is easily bested.

If you do not want to use a full length Pic rail, buy a full length Pic rail from Murphy Precision who makes them for the Dakota 76, cut pieces to fit the front and rear of the receiver and cut out the middle section. Then mount with Pic rings. I've cut out the middle of a Pic rail with a hacksaw, filed the cut face smooth, hit with black spray paint and bingo, instant bases with the middle open. No big deal.

Scope Mounts for Dakota Arms Rifles

Scope Bases for Dakota Arms Rifles

www.murphyprecision.com

 

[thoma018]

I'm not a fan of the vertical split rings. For mounting the horizontal split rings, I prefer a one piece Pic. rail. One thing forgotten that may be "overkill" but I think is important for applying the same ring torque to the horizontal ring 1/2s is to use a feeler gauge to get the ring 1/2s equal distance apart, left to right so the is even pressure on the tube.

 

[Rare Breed]

Unfortunately for most African style hunting rifles one piece mounts and Picatinny rails are verboten. So we use 2 piece mounts. Which are prone to alignment defects.

from Murphy rail manufacturing. https://www.murphyprecision.com/scope-bases/dakota-arms/
“Most modern rifle actions are machined to fairly close tolerances, but before the common use of CNC machining equipment, tolerances were much looser. In addition to any errors in the original machining, most rifle actions are polished afterward to remove any tooling marks. While this leaves a pleasing finish, most freehand grinding and buffing can lead to errors of several thousandths of an inch in critical areas. Without bedding, the only solution is to tighten the scope base screws enough to warp the scope base and rifle action sufficiently to make close contact. This warpage can lead to a host of accuracy robbing problems in both your rifle action, and scope.”

So after a thorough cleaning I install the bases and rings then check them with my slide alignment tool.

https://www.amazon.com/Scope-Ring-Alignment-1/dp/B0BV161PF3/ref=mp_s_a_1_8?crid=YU7ROCMYAEXS&dib=eyJ2IjoiMSJ9.Y6wBAnKUmCuKcghHdq62SpMWXMKs5iieOZAsaTeuW7OgrhxIM0ecrUYypb-kI6LOZG7A5aJM7PjuzX87d_nQNwsPk_Sojx8WsbLIdQ_RNVJXpFdYvAiV6fMnikuSLV_0Gm6lWTMtF7Nv3sDCXqcLCBgGy_8lW4ivmPONwVV7x5k4EgkoPY7nvNtxuAqqN5Jj2YYcjwFOfpXQ7vuz0FZsOA.Xr2dMVfHCzZRjQSh8BfqO0atXc2hnydVyfa2P8tUMwk&dib_tag=se&keywords=rifle%2Bscope%2Balignment%2Btool&qid=1785887883&sprefix=rifle%2Bscope%2Bal%2Caps%2C214&sr=8-8&th=1&psc=1

wow! You are giving me an education my friend! I mount all my scopes myself by my own eye then bore sight them the old fashion way by with drawing the bolt sighting on a target then aligning the cross hairs. Fortunately it has worked well for me but my max range is 350 yards and this has enabled me to do that with ease. Any thing beyond that I am just not confident

 

[SCHUNTER73]

Thanks for sharing your process and the visual aids. Very insightful. Like RB above, I have. Or been as thorough before. Will try this route when setting up my new scope soon.

 

[RLL]

Most hunters do not go to the extremes as the extreme long range guys do. Benchrest and the 1000 yard to 2 mile guys must perform these mundane tasks.

Also the owners of expensive optics that want their scopes operational and defect free.

Unfortunately my slide alignment tool showed a slight bind from the Talley rings. If I was using a more robust scope tube like
Nightforce Atacr, S&B or Tangent Theta I would have called it good. But I was mounting a 1” tube Swarovski so needed more precise alignment to eliminate 100% of any bind or high spot contact points.



View attachment 782141

Darcy Echols also use to manufacture 30mm and 1” alignment tools, and have slots cut vertically through the tool for tightening 2 pieces bases to the receiver in perfect alignment. Though not often used, its been a favorite to ensure square, bind free scope alignment. The tool has helped solve several ring/scope issues. I returned a pair of Leupold rings and bases on a model 70 due to being so far out, lapping was not going going to square it up.

 

[Altitude sickness]

Tex.416, I agree 100%. The vertical split rings are a PIA to get installed correctly.

With horizontal splits. You simply level the rifle by placing the reference level on the action while laying in the vise. Or rear sight base.

Get the rifle to level and place the barrel level.

Then move the reference level to the lower half of the horizontal rings. To ensure they are square with action.

Then place the scope in the lower half of rings.

It’s a much easier process.

It’s worth repeating that Horizontal rings are a PIA to install correctly.

Some engineers say the vertical rings are stronger due to both sides being dovetailed into the base. They also contend that although more tricky to get correct. Vertical are actually less likely to put a twisting motion on the scope as the bolts are tightened because both sides are locked in place.

The horizontal rings can shift left and right as each sides bolts are tightened. As the ring moves left or right it grabs the scope and twists it left or right making it more difficult to get the crosshairs perfectly straight.

This Dakota will be run through the mill out to 500 yards. If it’s not “dead nuts” and tracking accurately. The Talleys will go into the scope ring purgatory box. And I will order a pic rail from Murphy Performance.

 

[Altitude sickness]

This rifle will be one of 3 traveling to Utah for one of my fall rifle elk hunts. I may be over preparing. But the tag took 23 years to draw.

 

[Altitude sickness]

Something to consider when building a custom rifle. Do you need a raised rib for the rifle’s intended use.

As you can see in the pictures. The scope bell barely clears the raised rib.
@Mark A Ouellette and I were discussing last week. For a longer range caliber, is a raised rib a waste of money?

It surely looks good and for using irons is of some benefit. But I would think the benefit is to the shorter effective range DG calibers without a scope.

The raised rib forced me to use taller rings. Luckily my cheek weld, eye relief and scope height worked out in this case.

 

[Racer00]

Jay, on my Dakota Traveler 416 Rigby with a 338 Lapua barrel, I had the same issue with having to raise the ring height to clear the rib with the scope bell. On my 338 LP barrel, the raised rib was only secured with two screws. I removed it and installed plugs in the holes. Kept it clean and I was able to maintain a lower scope height.

 

[Altitude sickness]

Thanks Racer. It appears mine is silver soldered only no screws.

 

[Racer00]

Ahh. I get that. I was actually surprised mine came off so easily. Good luck with your elk hunt. I have 17 points in Utah. My number will come up soon.

 

[RLL]

I would add, beware of scope bubble levels to ensure proper stadia/scope hair alignment…the internal erector and stadia are not always true to level with the scope body windahe and elevation nobs.

Use the levels as well to get started but always visually verify with a plumb line before tightening down…a 2-12x scope enlightened me of this potential manufacturing quirk.

 

[Altitude sickness]

Great point. Plumb bob is most accurate for vertical reticle alignment.