20 moa rails and scope centers

[damnbiker]

I have two savage rifles, a 10 HS precision in 308 and a 112 magnum target in 338 lapua. Both come with 20moa rails, both shoot 3/4 moa or under.

My problem is that on my 308 with a PST 6-24, my 100 yard zero is 3 MILs over the scope center. The PST has 20 Mils travel, thus I only have 7 Mils left for elevation which brings me to about 800 yards. I actually bought another 20 moa rail off Midway and it gave the same zero.

On the 338 with a Razor Gen I, my 100 yard zero is damn near center of the 38 Mil internal elevation travel. I still have enough travel to go 1500 yards on this because the Razor is awesome.

The windage zero is near center for both, so that is good.

Do I really have 0 moa rails? AND midway shipped me the wrong product? Or do BOTH my rifles shoot low?

I'm confused.

[ExtremeX]

So you replaced a 20 MOA rail with a 20 MOA rail and you still get the same zero? I would not expect any change there unless ur trying to stack them somehow and make a 40 MOA rail.

Why not just buy a 30 MOA rail or something like that for the PST?

You should be able to tell just by looking or measuring the rails... maybe they messed up, maybe there is nothing wrong.

[NorCalFocus]

How high are your rings? Is the scope mounted higher than needed?

Have you checked the rails against the action to see if it needs to be bedded?

Lastly have you checked that 3 mils above mechanical zero or did you just dial up from zero and count 7 mils?

[damnbiker]

Yes, I replaced the stock 20moa rail with another 20moa rail to make sure they didn't give me a 0moa rail from the factory. It didn't change, which confirms I did have a 20moa rail from the factory. I also swapped the Razor onto my 308 and confirmed approximately the same behavior, so scope isn't broken.

The savage action has the rear mounting holes slightly lower than the front, so the rail naturally cants forward when placed on a flat surface. How do I measure unless I buy another 0moa rail?

I am using the lowest rings possible, which makes for scope center approx 1.8" above bore center. Typical height I believe.

The rails all mount flush with no play, no issue there.

I did check that its 3mil above mechanical zero by counting from turret limit.



I guess the main question is: for those of you that have 20 moa rails, where is your 100 yard zero compared to scope mechanical center?

I expect a 0 moa rail to produce a zero near mechanical zero, and a 20 moa rail to produce a zero around 5.5 mil UNDER mechanical zero. In my case with the PST, if I had a 0 moa rail, then my zero would be 2 mil from the max elevation?

[NorCalFocus]

Your right on with your assumptions. I've never checked my mechanical center vs zero because I have plenty of up travel to 1000 yards in my scope. Which means I'm below the mechanical zero. (20 MOA rail on a 700 in 308, Viper HSLR scope)

Something is out of alignment. I'm going to guess the barrel is not centered on the action, or the action/barrel aren't sitting correctly in the stock. Not completely uncommon in factory rifles.

[damnbiker]

I just find it strange the BOTH my rifles do this. I guess since the rifles shoot GREAT, I can just buy a 40moa rail and be done.

Anyone else checked mechanical center vs bore zero @100?