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Discussion Starter · #1 ·
The past two mornings I did some barrel break-in and attempted to sight in my new rifle.

The challenge is that even with the scope dialed all the way down I am still shooting high.

The equipment:

  • Rem 700 SPS 20" .308
  • Vortex Viper PST 6-24x50 FFP EBR-1 Reticle (MRAD) in TSP rings on a Seekins 20MOA base. The center line looks to be about 2" above the center line of the barrel.

Distance ~62 yards - hitting about 9.5 inches high with the scope dialed all the way down.

The first thing I thought of was the 20MOA base must giving me too much added elevation for the scope to accommodate at such close range, but given that the scope has 19 MRAD of elevation adjustment - 20MOA base should only be moving my scope adjustment by about 5.5 MRAD. Assuming a zero cant base a 100 yard zero would probably be about 9-10 MRADs from bottom, it seems to me the 20MOA base would only be bringing my 100 yard zero down to about 4.5 MRAD from bottom.

My buddy suggested we were cranking the scope the wrong way, so what the heck, we dialed the scope up 5 MRADs and indeed the round hit another 12-18 inches higher. (Something in that ballpark)

So we confirmed we are indeed dialing the scope all the way down, but I must be doing something very screwy. (Or something is wrong with the scope. Possible, but I'll assume I am the one doing something before I start blaming my equipment.)

Any thoughts or suggestions?

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Have you dialed any windage? If the internals are pushed to far to one side it can limit you. Have you dialed the scope from bottom to top to make sure you indeed have all the travel available? Have you removed the turret and seen if there are any shims in there? Lastly, did you check your scope base to make sure it did not need to be bedded?
Just some of the things I think of.
Are you sure that's a 20 moa base? The back end looks a bit tall compaired to my nightforce 20 moa rail.


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My first thought was "does he have the rail mounted backwards" but Reminton has different spacing on front and rear mounting screws so that can't be it. However, the manufacturer of the rail may well have drilled it backwards

My basic rule for situations like this is to take it apart and start over. Re-install, making sure that there is nothing keeping the rear of the rail from fully seating on the action like a burr, etc.

Mount the rings on the rail (on or off the rifle) right next to each other and check the bottom half with a straight edge to make sure one isn't higher than the other by a few thousandths.

Check to make sure the scope isn't adjusted to one extreme or another for windage. If the mount holes are drilled off-axis you could have the erector (the piece that holds the crosshairs inside) off to one side and since the scope tube is round, this can limit it's travel.

I have one rifle that is like this and in order to mount one of my scopes with limited elevation travel I had to put a .008" shim under the front of the rail.

Another solution is to replace the rings with Burris Signature Zee Rings. They use offset inserts that allow one to correct for mis-drilled holes or not so accurate angled rails.
 

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Discussion Starter · #4 ·
Thank you Gunguy308 and Deadshot2!!

The quickest to check and most obvious given that I purchased this scope used was examine the turret for Vortex CRS Zero Stop shims... sure enough there were two shims in there!

I did everything the YouTube videos said to check to see if I needed to bed my rail. I expected that I would need to bed it, but it did not appear that was the case. The packaging said it is a 20MOA base, but it is not like assembly monkeys never put the wrong item in the wrong packaging. Being a noob at scopes so I would not know a 20MOA from a 40MOA cant just from looking, and I could have been wrong in my evaluation that the rail did not need to be bedded.

I don't think I have the windage cranked to one side, but I'll check that as well.

I'll take it back out this evening or in the morning and see how it shoots with the CRS Zero Stop shims removed. If I am still way off, I'll then start running through the rest of your suggestions.

Thanks again! I'll post the results.
 

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Thank you Gunguy308 and Deadshot2!!

The quickest to check and most obvious given that I purchased this scope used was examine the turret for Vortex CRS Zero Stop shims... sure enough there were two shims in there!

I did everything the YouTube videos said to check to see if I needed to bed my rail. I expected that I would need to bed it, but it did not appear that was the case. The packaging said it is a 20MOA base, but it is not like assembly monkeys never put the wrong item in the wrong packaging. Being a noob at scopes so I would not know a 20MOA from a 40MOA cant just from looking, and I could have been wrong in my evaluation that the rail did not need to be bedded.

I don't think I have the windage cranked to one side, but I'll check that as well.

I'll take it back out this evening or in the morning and see how it shoots with the CRS Zero Stop shims removed. If I am still way off, I'll then start running through the rest of your suggestions.

Thanks again! I'll post the results.
With the shims out, how much adjustment did you gain?

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A nice tool to have if you have a few discretionary $$ is a laser bore sighter that fits in the chamber. Cabela's sells one that it somewhat reasonable in price and fits .223's directly. For other calibers you just purchase a sleeve that the unit fits in so it's centered in the chamber.

A good tool for initial setup as it will get you close. I can see mine in average daylight at 50 yards. Great to set windage and some simple math will allow you to compensate for a 100 yard target, elevation wise.

Oh yes, it's also great for setting up an optical chronograph without having to run back and forth to look over the top of your rifle. :) :)
 

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You should have gained enough with the shims taken out.

But also move your target to 100 yards. Trying to get a sub 100 yard zero on with a 20 MOA base is tough.
 

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Since the scope was purchased as a used scope....consider the mechanical zero.

2. The importance of mechanical zero becomes critical when a scope is removed and remounted on many occasions and if the scope has been issued to numerous snipers over the years. If this is the case, much of the windage and elevation may already be taken out of the scope leaving the current sniper with a limited amount of adjustment. The method used to bring the scope back to mechanical zero is simple. All one has to do is turn the turret all the way in one direction until it stops. Once the turret wants to stop, do not force the issue. You can easily damage the scope by applying too much torque. At this point simply turn the turret in the opposite direction counting all of the clicks. Keep in mind that if you have a scope with a significant amount of minute of angle adjustment, this equates too many clicks. Once you have accomplished this divide the number of clicks that you counted by two (2). Then turn the turret back that amount. If you counted, 200 clicks then turn the turret back 100 clicks. Repeat this same process for the other turret. If you started with elevation first, then keep in mind that the windage will not have as much adjustment.

Just a thought. Good luck
 

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I had a similar process going on with one of my scopes. It was a 65MOA scope and I had put a 20MOA base on it. After the 20MOA base on it still only had like 30MOA UP elevation instead of what should have been around 52MOA. I ended up buying a 30MOA base and just externally correcting the problem.

I later talked to a guy at the range with the same scope. He had two of them. One of them zero'ed as you'd expect and the other one was 5.5Mil off from the other one. Same bases, scopes, rings...etc.

All 3 scopes were a Vortex Viper PST. Given that they have a lifetime warranty; at some point I'd consider sending it back OR putting a 0MOA base on it. Seems like either would fix your problem. Before putting on a 0MOA base and externally fixing the problem I'd check to make sure that you do in fact have the correct 19Mil of full travel up and down. Just crank the scope and count your clicks.

Good luck




Edit: Sent mine in this week and they fixed it;)
 

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Suggestions?

Shoot further, then it will drop in there. :p

-Nate
 

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I'm having the same problem with my rifle. Tried to zero at 300 and its crazy high. Its got a leupold mark5hd 7-35x56. I got a 20 moa base and a 20 moa mount. Surely I wouldn't need to go clear to 400?
 

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I'm having the same problem with my rifle. Tried to zero at 300 and its crazy high. Its got a leupold mark5hd 7-35x56. I got a 20 moa base and a 20 moa mount. Surely I wouldn't need to go clear to 400?
Only pain in the butt with the Mark5 HD is having to adjust down .5 mils at a time to zero.

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I suppose I just need to zero out farther or get a new mount
make some shims out of a measuring tape, I think they r .012 not sure take off your base set over the shim drill holes then add the shims to the front, this will raise your scope and you will be good to go, or shim till you get your desired ht, it won't take much you can do this till you get new rings or figure out the issue
 

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their is a formula somewhere on the net that tells by .001 how much moa is, been a long time since I shimmed, or use burris z rings
 

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I suppose I just need to zero out farther or get a new mount
What exactly did you do when you first went to zero? Did you turn down below the zero stop, loosen the screws and turn the turret back to till it locks then tighten the screws and repeat until your adjusted down far enough? I mean that scope has 35 mils of adjustment. More than enough to account for 40 moa of rail/mount.

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Its down passed zero a few clicks. I've got almost 3 revolutions of adjustment for elevation. Its shooting a few feet high at 300
 

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Its down passed zero a few clicks. I've got almost 3 revolutions of adjustment for elevation. Its shooting a few feet high at 300
2 feet at 300 yards is like 2.2 mils. There should be plenty. I had to dial my wife's scope 5.8mils down to zero. Do you have a picture of your setup?

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