Correct scope mounting

[Nhoro]

Hi all, I bought a second hand rifle and took the scope off. I saw all sorts of things that I would change but maybe I am being a bit ocd. Vertical reticle was perfect when checked with a plumbline.
1. Front mount is at a slight angle to the scope. Surely this will bend the scope tube when you torque in the back mount ?
2. Both mounts have left and right screws that lock each mount from rotating. The 2 screws were uneven ie the mounts are pushed to the right.
3. Lastly, the top caps were tightened fully on the right and had about 3 mm gap on the left.surely that will also distort the tube as the half circle will be at an angle.

So in my mind, the tube should be unstressed and naturally pointing down the Bore when you start to zero. How much do thesethings impact the scope- does it make a difference ?

 

[tedthorn]

You are correct.
The scope should sit in two rings that are very much in line with each other and without stress

 

[BeeMaa]

Although not directly related to your above questions, eye relief is one of the most critical things to get right while mounting a scope.

To set proper eye relief, first the rifle must fit you when you mount it. Place a piece of painters tap along the top of the comb on the stock. Mount the rifle over and over again like you are going to shoot it. Have a friend mark on the tape where your eye falls on the stock. You should end up with several marks in about the same location and this is the natural position your eye comes to when the rifle is mounted.

Next is to find the eye relief for the rifle. Dial the rifle to full power and shine a light backwards through the scope. Focus the beam of light through the ocular lens (where you look through) and measure the distance from the ocular lens to the focus point. (ex. Let's call this 3") Do this again on low power for your second measurement, because low power will usually have a longer eye relief. (ex. Let's call this 3.5") Go right between the two numbers to get your eye relief. (ex. would be 3.25")

Now go back to your rifle and place the scope so the ocular lens is 3.25" (for our example) from the mark on the stock. Level the scope, loctite the scope, rings and all fasteners with 222. Now you are ready to bore sight.

 

[MMAL]

You can lap the rings to get them square to each other and the rifle. All screws should be torqued to the proper lbs. I personally do 20 lbs for the bases to the rifle and 15 lbs for the top rings to the base. And use loctite

 

[Firebird]

This can be as simple or as complicated as you want!
Check YouTube for “how to Mount a scope” and rely heavily on videos from midwayusa rather than videos downloaded by bubbas basement or similar. . .
I like to drill my base holes out and use 8/40 screws to start the process and I prefer Talley bases and rings-a machinist or a gunsmith can do it for you, I have a buddy that does mine.
No, those aren’t necessary but it’s small change for a crucial part of your set up. Tossing out cheap, worn out or broken parts-and it sounds like you have those, should be your first step

 

[fourfive8]

There are two things that can put the scope tube in a bind. The D&T holes or dovetails in the rifle itself or the scope mounts/bases. I'd make sure the mounts are correct for the rifle. If something is wrong with the mounts/bases, toss them in the trash as @Firebird suggested. Once correct mounts/bases are secure to the rifle inspect the scope as it is placed in the mounts. It should be readily apparent if there is an off axis or binding situation. A large deviation is no good and may require a competent gunsmith to handle. A small deviation can be corrected by using a lapping bar and lapping compound.

Once the scope is set in the mounts you can check to see if the mounts will line the scope up with more or less the center axis of the bore. Turn both windage and elevation adjustments all the way from one stop to opposite stop. Count the total clicks and turn the adjustment for both windage and elevation one half way. For example If you count 100 clicks end to end. Set each at the 50 click mark.
That is the theoretical mechanical center of the scope adjustment. Remove bolt and bore sight on black bull set at 25-50 yards or any distance where the visual image of the bull is easily centered in the bore. Ideally the scope reticule should more or less be centered on the bore sighted bull. Use a gun cleaning vise or similar to hold rifle steady during the process- easier that way. If the reticule is within a reasonable distance of the center of the bull, you are probably good to go. Makes sure things are tightened down, adjust the scope reticle to center of bull (bore sight) and shoot 2-3 rounds to check group and center of group. Shouldn't be too far off. Fine tune adjustments using 3 shot groups for preferred setting. For average scoped high powered hunting rifle I like about 2" high POI at 100 yards. For DG rifles I like zero at somewhere around 50 yards. Preferences vary. I don't shoot past point blank ballistic range of cartridge/rifle so the 2" high @ 100 is usually plenty and for most of my cartridges and guns that will yield a maximum point blank range of around 275 yds for average big game like medium PG or deer sized game. Point blank range simply means I don't have to add any extra elevation at longer ranges to make vital heart-lung area hits on the game I am hunting. I don't want to be guessing with Kentucky windage and elevation at that time- I want to only be concentrating on trigger squeeze and steady hold.

 

[Nhoro]

So just waiting for the range to open. I have aligned the bases with the scope. 2 piece cz bases. And I have centralised the scope in the bases. All set.