Can’t get scope boresighted.

Looking for a little advice. I mounted a Schmidt and Bender 4X16x50 double turn turret scope on a Christensen ridgeline using a Talley 20 MOA rail and Spuhr 0 MOA mount. When i try to boresight the rifle I can't quite get the reticle to zero. It is still a couple inches high. To be clear, the reticle starts way above zero and after maximum dialing it still is about two inches above the dot. I am using a Sightlite laser bore sighter. Does this mean I don't need the 20 MOA rail or do I need a 40 MOA.

I've never used a Laser bore sighted, as I think they are a waste of money. The rifle is not a laser and and the center of your crosshairs will not be dead on in regards to the laser as your bore is lower than your reticle. The laser will be a reference only.

Anyway, I would suggest starting at 25 yards and get it so that it is shooting approximately .5" low straight below the bull. Then move back to 100 yards and make adjustments (should be really close.

Good luck,
Steve

I would try shooting it at 25 yd to see if it really is still high. If it is then check to see if the zero stop is blocking movement in the down direction.

You didn't mention the distance you were boresighting with the laser. If you manually look through the bore with the rifle in a gun vise do you get the same results? 25-100 yards is best for the manual boresighting.
I might have mis-understood your explanation, but it sounded to me like the laser dot was lower than the reticle sight picture and would only adjust lower than that. Which may mean it will shoot low and only adjust to shoot lower. Could the rail possibly be mounted backwards? A simple thickness measurement will affirm this (it should be higher at the rear).
Just a thought,
Randy

Also the laser at real close range as in a room will always show as low as the scope height (1-1/2 - 2"). The construction of the laser and fit of the bore guide can also contribute to its inacurracy.

I bore sight by looking down the bore at a Target on my wall at about 25'. I have a mark on the target about 2" high. (I have never measured it......I made the mark with a rifle that was already sighted in.) I find with most guns, if the bore is centered on the bull, the cross hairs should be on the mark 2" above the bull......This has never failed to get my on paper at 100 yards. I would assume the laser would be the same concept......Also many people have issues when bore sighting because you have to tweak your thinking on what way to move the reticule.......If your cross hair is above the target when bore sighting, realize that you will be hitting low, because you will lower the barrel to get on target. So to move the reticle DOWN towards the target, you have to click the scope UP....... If you center the bore with the crosshair at close range, you will be shooting way high due to the different planes of view and bore.
I only Have one rifle that I couldn't zero at 100 yards with a 20MOA base......My thoughts are it probably closer to a 25 or 30 base, So I think you should be able to get it zero'd with the base you have. Hope this helps!

+1 on boresighting by eye. I have a utility fence with a red danger sign at 100 yards, that I use. I haven't been off by more than approx. 2" when I get to the range to dial the scope in.

+1 Always thought the bore sighter was invented for gas guns, pumps and levers.

CO_Guy said:

+1 on boresighting by eye. I have a utility fence with a red danger sign at 100 yards, that I use. I haven't been off by more than approx. 2" when I get to the range to dial the scope in.

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I've got a 3" blaze target spot on a white background out in the back yard about 65 yards from the dining room table. I use a gun vise on the table looking out through the sliding door. At night I bring an led flashlight out there and set it to look back at the house. Ready to shoot in the morning.

Thanks for all the thoughts guys. I think I found the problem. It is a zero rail not a 20. I had it sitting next to a couple of others 20 Talley MOA rails I am going to use on other projects and didn't notice it was a zero. I do have a follow up question. I am going to get a Murphy precision rail for this setup. They say get 1/2 of your total MOA travel in a rail(40 MOA total adjustability, 20 MOA rail). This S&B has 56 total MOA on the turret. Since I never quite reached zero with the flat rail should I get a 30 instead of 20 MOA rail?

20 is enough.

Something in this conversation is totally wrong. If you have a flat rail, the most you should need to adjust for zero is a couple MOA in either direction. And that is starting with the scope in the center of its motion as shipped from the factory.

Not being able to zero suggests that something is off by more than 20 MOA or half the scope movement. If you put a 20MOA rail on a rifle, the scope is pointing down, not up. Shooting further requires the barrel being raised , while the scope axis is inclined downward so you can still see the target with the barrel elevated. Think about raising the rear sight on a surplus rifle for long distances. This is the same thing. So looking through the scope after first putting it on the base, the crosshairs should be below the point that the barrel is pointing at. If the crosshairs are above the barrel aim point, the rail is on back to front. You willl find that to raise the aim point you will have to rotate the turret in the "down" direction.

You need to check out a few of these concepts and report back.

After further research I found a review on the 6mmBR website. He loved the scope but specifically mentioned that he found you need at least 29 MOA of angle on the rail. When you dial for long distance you are lowering the reticle which makes you raise the barrel. Since I had to use all the adjustment to get near zero hopefully the 30 MOA rail should correct this. I thought about the possibility of the rail being reversed but it is not possible the holes won't line up with the rail reversed. Since it turns out I used the 0 rail accidentally it shouldn't matter even if you could.

m3mike said:

After further research I found a review on the 6mmBR website. He loved the scope but specifically mentioned that he found you need at least 29 MOA of angle on the rail. When you dial for long distance you are lowering the reticle which makes you raise the barrel. Since I had to use all the adjustment to get near zero hopefully the 30 MOA rail should correct this. I thought about the possibility of the rail being reversed but it is not possible the holes won't line up with the rail reversed. Since it turns out I used the 0 rail accidentally it shouldn't matter even if you could.

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I don't think that anyone can follow your logic. The distance you are boring to has significant impact to understanding what's going on.
Now the the more the scope base is the more ups you get but when using a laser, the laser will straight through the bore but the scope will be more down. So if you are bottoming out on downward adjustment it's because you're using a bore sight to close more than likely, because of the angle of the scope being on that base and the scope height to bore axis.

Laser bores are virtually worthless, and are a means to get a rifle on paper. Best at 25 yards. Getting on to 100y, if you are on paper at 25 or 50 shouldn't be an issue. 10 rounds got the whole process tops.