Mounting scope in line with bore?

[andrewctillman]

I have a very accurate Remington 40 x and am re-installling a Leupold Mk4 10 X target scope w 30mm rings. the rings have a 1/2 inch hex nut on left side. They unscrewed without alot of tension on socket set wrench.

What sort of protocol do you guys use for mounting a precision optic on the bases? this is a two piece set of rings, not a single mount, so how do I insure it is mounted in line w the bore and not canted to left or right?

I have automotive torque wrench but nothing more sophisticated than that.

Advice appreciated.

 

[nvbroncrider]

What bases and rings do you have are they standards Picitinney dual doves weavers?

As far as mounting I have the Wheeler mounting kit with the levels and lapping kit. It works really well.

 

[Ridgerunner665]

Don't buy cheap bases...I have had several over the years (Warne, Weaver) where the holes were drilled off center or crooked...the Leupold QRW/PRW 2 piece bases are a pretty safe bet...they are QRW compatible so the machining tolerances are held pretty dang tight...measure the bases you have (edge of holes to edge of base) on all sides...if the measurements are even, you're golden.

That said...
Alignment with the bore is mostly dependent on the receiver being drilled properly...your 40x should be OK...700's, not so much.

As mentioned...the Wheeler kit is money well spent...I don't have the complete scope mounting kit...I only have the FAT wrench and the Professional Reticle Leveling System.

When I seat rings into bases...I tighten them while making sure they are hard pressed to the front of the slot in the base...not sure it helps much, but it always seemed logical.

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[JD338]

Don't buy cheap bases...I have had several over the years (Warne, Weaver) where the holes were drilled off center or crooked...the Leupold QRW/PRW 2 piece bases are a pretty safe bet...they are QRW compatible so the machining tolerances are held pretty dang tight...measure the bases you have (edge of holes to edge of base) on all sides...if the measurements are even, you're golden.

That said...
Alignment with the bore is mostly dependent on the receiver being drilled properly...your 40x should be OK...700's, not so much.

As mentioned...the Wheeler kit is money well spent...I don't have the complete scope mounting kit...I only have the FAT wrench and the Professional Reticle Leveling System.

When I seat rings into bases...I tighten them while making sure they are hard pressed to the front of the slot in the base...not sure it helps much, but it always seemed logical.

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+1

JD338

 

[longrangehunter]

From what you're saying most rings that use a 1/2" hex head bolt require 65 in-lbs applied to them. As far as mounting the scope to the axis of the bore I wrote an article on this very subject that I use. I repost it below:

Ok, I'm not sure if this is new or old news, but it works very well for me and making sure I can hit exactly where I'm aiming if I've done everything else right, so here goes.

The scope should be mounted so the cross hairs are inline with the bore axis. Here's how to set it up so that as you dial into the elevation the bullet tracks correctly.

Have a known accurate load for the gun to do this test, and/or as accurate as the gun will hold at 100 yards/meters.

After mounting your scope and it is sited in, attach a large piece of cardboard at least 4' in length and mark a plumb line on it as long as you can in the middle. Place a mark, X or whatever 6" from the bottom on the plumb line drawn. Depending on whether your scope is in Mils, or MOA and the graduation of the scope come up 18" from that mark at the bottom and place another X on the plumb line, and one more 18" further up on the plumb line, the last one should be at 36" from your bottom mark. If you have a lot of turret adjustment range then you could go up another 18" but it is not necessary.

Note: This may need to be varied" IF" your scope does not have enough elevation range in your turret scope adjustment? If you don't have 36" of adjustment at 100 yards this will still work the same for setting up the scope, only your bullet will hit the cardboard further down from the upper most mark used.

Ok, here's what you want to do. Aim at the bottom X placed on the plumb line and fire one shot. It should be very close to the plumb line mark, either dead on, right or left but it wont really matter.

Aim and fire a 2nd shot at the bottom X only this time dial in 5 mils or 17.25 MOA into your elevation adjustment on the scope. The bullet hole should land on the same side and distance away from the plumb line as your first shot, or be dead center of the plumb line, either case it should be the same! And that is the important part!

Dial in another 5 Mils or 34.25 MOA and fire a 3rd shot while still aiming at the bottom mark you placed on the cardboard. Your bullets hole(s) should still be tracking the plumb line you marked and the same distance from that line drawn!

Ok, if you mounted your scope correctly and your round is accurate enough the bullet holes should be moving up the cardboard in a vertical line that is plumb (straight up and down). If the round fired at the bottom X mark is on the RIGHT side of the plumb line and the 2nd round is dead center and the 3rd is LEFT of the plumb line your scope will need to be turned Clockwise in your rings! Or Counterclockwise if the rounds fired are tracking Left to Right.

What your looking for is that as the adjustment(s) are dialed into your scope, that it tracks correctly up and down the plumb line drawn. If it doesn't, the amount needed is a very small turn clockwise or counterclockwise, and I mean very small unless you're way off.

Not only will this tell you if your scope is mounted properly inline with the bore, your scope should also be tracking correctly for the amount(s) of adjustments made. ie: 5 mils should change your POI 18" and so on.

This only needs to be done one time once successful. It is a trial and error method but this is the best way to make sure your scopes cross hairs are inline with the bore. Apply some masking tape with a line drawn on it to the rings and the scope so you can see the movement within the rings while turning.

This really only matters for extreme precision shooting as the distances become greater and greater. But you'll be happy you went through all this trouble in the beginning so as you begin your long range shooting your bullets are where they should be based on your dope.

Good luck.

 

[woods]

http://www.brownells.com/search/index.h ... &ksubmit=y

aim out door or window to distant vertical or horizontal object and rotate scope till reticle aligns when bubble level. All cant out of gun and barrel of scope aligned with bore

Install anti-cant device

http://www.scoplevel.com/

done

 

[Ridgerunner665]

I think maybe I misunderstood the question a little...

I thought he was asking about the entire scope being in line with the bore (side to side)...that's what my previous post was directed at (ill fitting scope mounts/bases)

Reticle alignment is a much simpler task.

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[longrangehunter]

Actually it's not as simple as mounting any level or levels to the action and scope. There are a number of guns that the bore is not perfectly centered, the scope mounting screws not perfectly centered on the action, and to the center line of the bore, etc.
If it were that simple the method I described above wouldn't need to be done for Long range precision shooting, but for the man or woman shooting under 200 yards that quick down and dirty method will not, albeit not technically correct.

 

[HOGWILD338-378]

Good read and some of it should apply to all scope installs !

http://www.longrangehunting.com/article ... ment-1.php

You can install a canted scope on a canted rifle and it shoot straight but that just makes my skin crawl :lol: and shooting short range for a hunting application it's not as critical but I like doing thing's once and all my long range rifles I let my smith install as he has probably one of the best methods setup as he is a competitive LR Comp Shooter! Plus he runs a worksheet on alignment and the errors the scope has in the travels of the scopes adjustments!

 

[Oldtrader3]

Buy and install good bases and rings, I use TPS and they are straight. Then sight in at 100 yards and shoot 200, 300 what ever you can. if the bases are not straight, parallel and low T.I.R. the groups will move at other yardages, striking not where they are supposed to be?

 

[BeeTee]

Bubble levels, by themselves, aren't very accurate.

Using a plumb line on a target to verify scope/bore tracking or crosshair alignment requires that a plumb line be used to level the rifle every time it's used in the field as well. Otherwise, it's just an interesting (and possibly fun) exercise.

Unless you're a 1000+ yard shooter, precision crosshair alignment isn't all that critical. I've seen a lot of rifles with varying degrees of misaligned crosshairs reliably take game year after year. It's more an OCD sort of thing. I try pretty hard to get them aligned correctly, but I don't obsess. I want the horizontal wire to be level when the rifle is sitting on the bipod on a level table. That's it.

 

[andrewctillman]

Thanks Guys,

I am a 1000 + yard shooter, which is why I asked about alignment.

All of this helps.

 

[HOGWILD338-378]

http://www.scorehi.com/precision_scope_mounting.htm

I have let Charley do this on several of my rifles and it is way more accurate than anything I can come up with as I do not have a jig like he uses and the software he uses to run his work sheet and it's more about knowledge and doing it the best way possible which is basically what Charley has done and I have seen nobody else do an install like his! I like the last sentence or 2 as when it just does not shoot it is just not going to ever be a straight shooter basically :mrgreen:

 

[jimbires]

here is another article on this . I didn't read the article hogwild 338-378 linked up , this is a different one . I use this method .

http://www.longrangehunting.com/article ... larity.php

 

[SJB358]

That is the one I have always wanted to try Jim. Might just try it when I get the new scope mounted up on the 35 Newton. Shouldn't be any big trick to do it at 200 yards..

 

[jimbires]

I do it at 100 yds , Scotty . I use my 100 zero then I turn up the elevation 20 - 30 minutes and see if it tracks true .

 

[SJB358]

Oh, okay, makes sense Jim. I read about it in the ballistics books too. Has to be something to it. I like how they lined it out at LRH though.

Might give it a try tomorrow.

 

[jimbires]

Scotty ,if you have a rifle level be watching it close while doing this . if you are canting the rifle it will never track true . I think the main reason for doing this at 100 is it helps with ; wind conditions , mirage ,and the human factor . you know , the nut on the trigger ! ha ha

 

[SJB358]

Got it. Makes sense to me. Wanna give it a try tomorrow.

 

[HOGWILD338-378]

Some of the tracking issues are built in and can never be removed as my link speaks about running a worksheet on the operation of travel and is off sometimes as much as a 1/2 a minute at different ranges and is just something ya have to live with ? The process they use also gives them a true number on you elevation and windage values that say they are 1/4 at 100 yds but are actually close but not exact and every scope has different numbers ! Not many people even worry about these as they think the manufacturer has them precise and Charley's process can give him exactly how precise the manufacture got the travels near to perfect! He gives you actual number values clicking from top to bottom of the travel ! Never heard of anyone having this set up but Charley is a Comp Shooter and from what little I have found out about him he is sharper than the average Smith ! Glad to have him close as well as he is best in town !