Rifle Scopes Viper PST Running Out of Elevation

[TXSTDU]

Weapon System Specs:
Remington SPS Tac .308
B&C A5
Viper PST 6-24x50 Mil/Mil
Warne Tactical 20 MOA base (Installed Correctly)
Warne Tactical Med Rings



Today I finally got a change to stretch out my PST and shoot to 1000. So far I have been shooting lights out at 100 with this scope and had no issues. Today when I when to adjust my scope for for elevation I was able to get 6 mils of elevation and that was it. I have looked everything over and nothing is wrong. I am at my wits end to what to correct or change. Do I need a higher MOA base or lower rings? I don;t think this is the answer but could be. What else should I be looking into?

I had a Falcon Menace on this same gun in the same rings and bases and had well over 10 mils of travel. I am worried that this could be a problem with my scope and not the gun.

 

[BigJohn141]

The PST has 19 mils of travel, half way should be 9.5 mils plus the extra 6 down for the base should leave you with roughly 15.5 of up, give or take a mil or two for zero. Something isnt adding up. Maybe take a pic of the setup?

 

[lead ƒarmer]

You should have roughly 15 mils of useable elevation if everything is set up correctly. Either the base is on backwards or the scope has something wrong with it.

 

[SouthFork]

So a standard Vortex Viper gives you 65 inches of travel at 100 yards on elevation (65MOA).

What is the total travel on your scope at 100 yards?

Easiest way is strap your rifle into a lead sled or similar. Track your reticle down and bottom it out, and then do the same the other way. If your reticle isn't giving you 65 inches at 100 then you should send it back. I am talking in inches/moa, as you can post a couple of yard sticks or targets together at 100 yards and its the easiest way to check.

I have two conclusions.

1. Your scope is not aligned and you are at the bottom of your elevation already. That could be from not installing the scope correctly.
2. Your elevation turret is messed up somehow.

 

[TXSTDU]

Up close of base



Scope overview



Height over bore



Elevation turret at 100 yard zero.


Would it help to put my rear ring more over the elevated section at the rear of the base?

 

[TXSTDU]

These were uploaded from my phone and the images look small. Just click on the and they will show a larger size.

 

[Genin]

Well holy hell you can tell that you are at the top of your elevation range for your 100 yard zero. It appears as though the base is installed the correct way so it's not backwards. Is there any way that your rings are messed up? Maybe the rear ring is just slightly out of spec causing the scope to dip.....not quite sure but your 100 yard zero should be far more to the bottom of your elevation range. It's not the scope.

 

[TXSTDU]

What would be the best way to measure the rings to see if they are in spec?

Also I checked and I am sitting at 14mil of elevation for my 100 yard zero.

 

[Rob01]

How much windage did you use when zeroing? When you use alot of windage it cuts down on the elevation available as it pushes the erector to one side.

 

[Jethro3898]

This isn't your problem, but it looks like the erector housing is resting against your front scope ring.
It would probably behoove you to keep a little space between the two.

I shot with a guy who did this to his scope one time and couldn't keep his scope zeroed.

 

[bodywerks]

First off, your forward ring is too far back and your back ring is too far forward. Fix that.
As for your elevation issue i wouldn't be surprised if its the scope that's the problem. You hear so much about vortex's outstanding customer support because so many people have had to use it.
You should have at least 16 mils of total travel (more like 17-18 optimally). Regardless its easy to verify. Turn the turret all the way down until it stops. Then count the number of mils you have up until it stops. Whatever that is divide in half and then shoot it. With a 20 MOA base you should hit around 15-17inches high, or thereabouts, at 100 yards. This will tell you whether or not your reticle is centered properly.
If you aren't getting at least 16 mils total travel or if your reticle isn't centering properly, send the scope back for some excellent customer support...
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[TXSTDU]

Well I got my head out of my rear and fixed the rings. This helped me pick up an additional 1.3 mil for a total of 7.3 vertical elevation over zero. Other than what I have done I think the only other way to help is to add a higher MOA base.

 

[Outdoorsman9]

The scope looks angled up... maybe it's just me but it looks like the base is on backwards

 

[bodywerks]

That a band aid fix. have you measured your total elevation travel yet? 7.3 mil of dial up from a 100 yd zero is an indicator of something wrong with the scope, even if it was a 0 MOA base.
Assuming nothing wrong with the rifle and you actually do have a 20 MOA base, you should have something like 12 mils of elevation available.
If you only have 7.3 its time to send your scope in. I've heard of this before with the vortex pst line.

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[Outdoorsman9]

You're talking out your ass right now bodywerks. Where you are at in the elevation travel after zeroing the rifle has little or nothing to do with the scope. Most of the time it has to do with something on the rifle being misaligned or not level. Start at the ground up and double check everything. You'll be even more pissed if you send the scope in and they tell you nothing is wrong.

 

[TXSTDU]

It is an optical illusion. The scope sits level (it is resting on the bipod). I am 100% certain the base is on correct and is a 20 MOA base. I did measure the elevation and got 20 total Mils I then set the scope at the half way point and went and shot. From there I had to come up another 2.7 mils for dead on at 100 yards.

 

[Outdoorsman9]

I see that now with one of your earlier pictures. There are a lot of thing is could be, but a simple solution without seeing a gunsmith would be to just get a higher MOA base.

 

[bodywerks]

Ease up there bud.
The first thing i asked him to do is find out how much total travel he has.
If he has the 18ish mils of total elevation travel then it is likely not the scope. But he has yet to tell us how many mils total travel he has.
Even if he does have the 18.9 advertised mils and dials down halfway, it is possible the erector assembly is effed up and not actually putting the reticle in the center.


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[RFtinkerer]

Just send it in. They can verify if it's on spec or not. We get stuff back in at our company and send it back NFF (no failure found) all the time. Then diagnose the installation issue. Eliminate the variables one at a time, and it sounds like you eliminated the most obvious base reversal, so...

 

[bodywerks]

You're talking out your ass right now bodywerks. Where you are at in the elevation travel after zeroing the rifle has little or nothing to do with the scope. Most of the time it has to do with something on the rifle being misaligned or not level. Start at the ground up and double check everything. You'll be even more pissed if you send the scope in and they tell you nothing is wrong.

You must have also failed to read that he had a falcon menace on this rifle with the same base and rings and had plenty of elevation. Its in his first post.


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[bodywerks]

Its basic math/common knowledge that a bullet drops hardly at all at 100 yards, less than an inch.
Assuming a 1 inch drop and a 2 inch scope height and a 0 MOA base and everything perfectly centered, the bullet impact will be about 3 inches below point of aim. Now add a 20 MOA base and keep scope settings the same. The bullet will now impact about 18 inches high. Assuming the reticle was properly centered and you dialed down the 5 mils to get on target at 100, you should now have about 14 mils up up elevation.
Simple math. Something would have to be seriously wrong with his rifle or scope mounting set up to only have 7.3 mils of up-like a washer under the front of the scope base.

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[bodywerks]

It is an optical illusion. The scope sits level (it is resting on the bipod). I am 100% certain the base is on correct and is a 20 MOA base. I did measure the elevation and got 20 total Mils I then set the scope at the half way point and went and shot. From there I had to come up another 2.7 mils for dead on at 100 yards.

20 mils is more than advertised. That's rare.
If you shot 2.7 mils low after "centering" the turret then something is wrong. I could see shooting 2.7 mils high with a 20 MOA base but not 2.7 mils low. Not by a long shot.
Obviously something is amiss. Put your falcon back on or borrow one from a friend and do the same thing - measure total elevation, center, shoot, observe impact. If the results are the same its something with the rifle. Not the same then time to send that vortex in. My bet is erector is shot.

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[TXSTDU]

Duplicate.

 

[TXSTDU]

Ok thanks. I have a school where i using this gun in 2 weeks. I will just deal with it until after the school.

 

[bodywerks]

You can check calibration of the turrets by going back to center and setting a yard stick up at 100 yards. Anchor the gun in a rest and set point of aim at the top of the yard stick. Dial up 10 mils and your poa should be at the bottom of the yard stick. Recenter and set poa at bottom and dial down 10 mils and you should see the top of the yard stick.
You could also use a laser bore sight at like 10 yards. Assuming about a 2"scope height and your 20 MOA base, your centered reticle (10 mils down from full up or viseversa) should be right on the laser dot.
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