Mounting a scope/level: the machinist way

[livetohunt]

So I did a quick job mounting my scope at home and it came out crooked as all get out to the action.

So I decided to bring my gun into work and see how good I could mount everything.

We have a massive granite plate at work so I was able to get the picatinny rail sitting flat front to back within .005" across the entire rail length. It's surprisngly flat, hardly any warp.
Then I clamped the gun to an angle plate and shimmer the angle plate until the rail was within .0015" of being flat to the granite. Double checked vs the action and it's .0025". Used pin gauge set to get the scope within .001" of being square to the rail. Tightened the scope down and then tightened the scope level with the bubble sitting dead zero.

Think I may finally be happy with a scope mounting job.

 

[jcampbellsmith]

View attachment 93250 So I did a quick job mounting my scope at home and it came out crooked as all get out to the action.

So I decided to bring my gun into work and see how good I could mount everything.

We have a massive granite plate at work so I was able to get the picatinny rail sitting flat front to back within .005" across the entire rail length. It's surprisngly flat, hardly any warp.
Then I clamped the gun to an angle plate and shimmer the angle plate until the rail was within .0015" of being flat to the granite. Double checked vs the action and it's .0025". Used pin gauge set to get the scope within .001" of being square to the rail. Tightened the scope down and then tightened the scope level with the bubble sitting dead zero.

Think I may finally be happy with a scope mounting job.

How did you level the reticle with respect to the granite block? Regards JCS

 

[Sykes]

Can I bring a few by?

 

[KyCarl]

Ours is about the same the plate is pink I use a Cordant Measuring Machine from Zeiss
to level everything. Then a small test laser sitting on the same plate set straight up (90degrees) to the plate Line the scope to the laser? Seems great!
But remember the stuff in the inspection lab costs way too much to have at home!

 

[Coach W]

Anybody ever used a string pendulum at distance to verify? I have a buddy that does, never even thought about it.

 

[MudRunner2005]

I just use this...

 

[Ingwe]

So even if your reticle is PERFECTLY level, doesn't it all go out the window the second you get on your rifle?

Do you actually aim and fire your rifle all the time looking at a bubble level that is perfectly aligned with your reticle?

I guess it's possible on a cement bench shooting targets but for hunting it seems like a waste of time.

 

[257Tony]

So even if your reticle is PERFECTLY level, doesn't it all go out the window the second you get on your rifle?

Do you actually aim and fire your rifle all the time looking at a bubble level that is perfectly aligned with your reticle?

I guess it's possible on a cement bench shooting targets but for hunting it seems like a waste of time.

I think the theory is that the reticle being perfectly level is only required when dialing the turret, which you would only do at long range. If the shot is far enough to have scope level affect to it to a noticeable degree, then you must take the time to shoot off a solid rest and check your bubble first.

 

[Ingwe]

That makes sense!

 

[livetohunt]

The reticle was leveled to the granite because the gun was clamped in place when I tightened the scope down. The flat on bottom of the scope was flat to the picatinny rail within a thou. The reticle is square to the body of the scope. Then I verified to a plum bob hanging a ways away.

I've taken some funky shots hunting and always been able to have time to get the gun nice and level. With a pivoting bipod and adjusting the legs adequately, and then a good rear bag, even in an awkward position half kneeling half laying on a side hill you can get the gun level.

You can trig the affected trajectory if your off say... 3 degrees and shooting 1000 yards (270 inches in my .300 win mag) I believe your vertical adjustment would be off 14 inches. So in essence dialing that at 3 degrees your true adjustment would be off 14" in Windage. Someone verify this I just woke up and I'm struggling with basic math.

 

[Ingwe]

I think you did pretty good...this stuff is way over my head.

I'm never shooting an animal at 1,000 yards anyway

 

[livetohunt]

Same theory applies to target shooting. I've never been happy with how I've mounted a scope level in the past, this way I know it's right.

 

[gohring3006]

I tried several ways, I always confirm with a tall target test. I always have to tweak it. Mainly because my price range of scopes, the reticles may not alway be exactly square with the scope body. I'm talking about 1000$ scopes. This is probably not a factor the higher you go up.
I do know, starting with a good bedded base, with high quality rings checked and adjusted with a scope alignment tool, will make it much easier.

 

[Rick Richard]

I am dizzy.