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Help figuring MOA of a rail base

 
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  #1  
Old 01-05-2010, 01:06 PM
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Help figuring MOA of a rail base

Working on a 700 LA Rem. I have a picatini rail base and I am not sure of the Manufacturer. All it says is [ REMINGTON 700 LONG ACTION 35 MOA]

I used this base with my IOR Tactical 6x24 and should have been close to bottom of adjustment @ 200. I was closer to the middle like a 0 moa base.

At the back screw of the base it is .430" thick. At the front screw, roughly 5.950" forward, it is .305" thick. Now I know the height of the receiver comes into play. But I am trying to figure where I lost 30 to 40 moa. Oh, rings are a set of 35mm IOR's and I have measured them and they are of equal height.

Thanks for any help.

Jeff
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Old 01-05-2010, 02:01 PM
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Re: Help figuring MOA of a rail base

Are you sure you're at the middle of the scopes travel? Have you counted it from end to end?

To calc the moa of the base you'll need one more piece of information. The height difference between the front and rear bridges of the action.

(inverse tan((.430-Height)-.305)/5.950)/60=base moa
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Old 01-05-2010, 02:15 PM
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Re: Help figuring MOA of a rail base

Quote:
Originally Posted by geargrinder View Post
Are you sure you're at the middle of the scopes travel? Have you counted it from end to end?

To calc the moa of the base you'll need one more piece of information. The height difference between the front and rear bridges of the action.

(inverse tan((.430-Height)-.305)/5.950)/60=base moa
Yes, I have 65 moa total in the scope, and I have counted them. From 100 yard zero I topped out at 27 moa.

I guess I could measure the action weights from a cleaning rod, but fear it would not be accurate enough. I figured since a 700 action is so widely used some one would have these numbers. Or, if someone had a similar 35 or 40 moa base to measure and compair or even a zero cant base to measure.

Thanks.

Jeff
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Old 01-05-2010, 06:14 PM
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Re: Help figuring MOA of a rail base

Quote:
Originally Posted by geargrinder View Post
Are you sure you're at the middle of the scopes travel? Have you counted it from end to end?

To calc the moa of the base you'll need one more piece of information. The height difference between the front and rear bridges of the action.

(inverse tan((.430-Height)-.305)/5.950)/60=base moa
OK, the height difference front to back is roughly .110" My calculator does not have inverse Tangent...

I am searching thr net but no luck so far.

Jeff
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Old 01-05-2010, 08:03 PM
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Re: Help figuring MOA of a rail base

Well, I never did get the math figured out, with out a calculator I am done. But unless I am wrong I found the problem. I put this base on the action. Then measured from the top of the bolt and also from the action rails (same thing) to the top of this base both front and back. She is parallel to the bore,,, Yes, stamped 35 MOA but in reality it is 0 moa. Am I just a lucky sob or what???




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Old 01-05-2010, 10:14 PM
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Re: Help figuring MOA of a rail base

Hmmm...that number doesn't add up. It should be some around .06".

that and my last number should be *6 not /6.

It's also called arc tan.



That definitely looks like a heavily tapered base. Looks like an EGW.
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Old 01-05-2010, 10:28 PM
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Re: Help figuring MOA of a rail base

Well, am I missing something here? If I mount the base and measure from the bolt or action rails up to the top of the base. Souldn't it be lower at the front of the base? I did this several times and it always came up with in a few thou of being parallel to the bolt.

Jeff
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