Rifle Scopes Need help - Problem with Vortex Viper PST 6-24 FFP

[TwoNiner]

I just purchased a Vortex Viper PST 6-24x50 FFP mil dot scope for a precision rifle build project. I am really excited about this scope and like all the features it has, but I've got a problem with elevation.

My first shots hit wayyyyy low in the dirt before my 100y target. I ended up zeroing it with the elevation turret almost maxed out: it only has 4.5 mils of elevation remaining. The scope itself has 19 mils of elevation adjustment.

I tested the scope out on my SPR AR15 and an American Defense AD-RECON-30 scope mount. I have $200 into this scope mount and AD is supposed to be among the best mounts available.

Any idea why this is happening? I'm worried that when I go to transfer this scope to my long range precision rifle that it won't have enough elevation to get me to where I want to go, around 1000-1300 yards.

 

[LSOSGT1109]

Re: Need help - Problem with Vortex Viper PST 6-24 FFP

Can you post a pic of the scope in the AD mount on the rifle?

 

[Flying Goose]

Re: Need help - Problem with Vortex Viper PST 6-24 FFP

does the mount or rail have built in MOA? is it possible that one of them is mounted backwards?

 

[Flying Goose]

Re: Need help - Problem with Vortex Viper PST 6-24 FFP

wait... that would account for the limited rotation left but not the first round going into the dirt, right?

 

[TwoNiner]

Re: Need help - Problem with Vortex Viper PST 6-24 FFP

The scope doesn't have any MOA built in and it cannot be mounted backwards as it is designed to project the scope forward. The AR is a normal flat top upper and I mounted the mount on the upper receiver as you'd normally do.

 

[LSOSGT1109]

Re: Need help - Problem with Vortex Viper PST 6-24 FFP

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: FlyingGoose</div><div class="ubbcode-body">does the mount or rail have built in MOA? is it possible that one of them is mounted backwards? </div></div>

That's what I was thinking when I asked him for the pic. I was thinking that if his mount was an MOA mount and if the scope was mounted backwards in the mount he would have had to use up alot of elevation to get it zeroed. That's not the case since his isn't an MOA mount and the scope is in the mount correctly. Honestly that was the only thing I could think of that would be causing the issue. I'm sure someone with more knowledge than me will chime in but until then I'm leaning toward an internal problem with the scope. If that's the case at least you can rest assured that Vortex will take care of it.

 

[bodywerks]

Re: Need help - Problem with Vortex Viper PST 6-24 FFP

Do you have another rifle to test the scope on? Without that mount? How far above the barrel does that scope end up with the mount?
One simple thing to do is measure to see if the scope is square to the barrel or canted up. If its canted up at all then there's your problem. If its square maybe its time for an MOA base.

 

[z71rat]

Re: Need help - Problem with Vortex Viper PST 6-24 FFP

Is this the first scope you have put on the rifle?? I had something similar happen, but it was due to a burr at the muzzle. The deflection of the projectile was enough to send it diggin in the dirt prior to the 100 yard target.

Check the muzzle... just a thought.

DK

 

[42769vette]

Re: Need help - Problem with Vortex Viper PST 6-24 FFP

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: z71rat</div><div class="ubbcode-body">Is this the first scope you have put on the rifle?? I had something similar happen, but it was due to a burr at the muzzle. The deflection of the projectile was enough to send it diggin in the dirt prior to the 100 yard target.

Check the muzzle... just a thought.

DK </div></div>

or a rail that is out of spec.

This sounds like a gun issure not a scope issue

 

[TwoNiner]

Re: Need help - Problem with Vortex Viper PST 6-24 FFP

I mounted my leupold 3x9 scope with a burris mount and discovered its zero was at 18 out of 24 MOA of elevation available. I only have 8 MOA which won't even get me to 600 yards with the .223 round. So either its a coincidence or I'm guessing that the upper on the AR is out of spec, or something is out of alignment, causing the scope to point high?

There aren't any burrs on the muzzle as I have a battlecomp 1.0 compensator on it. The scope sits about a quarter inch above the rail.

I'm thinking that perhaps my upper receiver is not square...