Author Topic: 20 MOA base shims  (Read 965 times)

Offline adrewiske

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20 MOA base shims
« on: April 26, 2010, 08:08:20 PM »
I recently bought a new new scope for my 22-250 and was looking for rings and bases. It's a 30mm tube and was thinking standard leupold rings. A friend of mine told me that people sometimes use a shim under the front base to give you 20 MOA more than what you would normally get. Is there anyone out there currently using something like this or just thoughts on this in general and the best choice/company to go with. Also is there a certain action you can use these with? My gun is a typical short action bolt. Thanks!
Andrew

Offline RGinIdaho

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Re: 20 MOA base shims
« Reply #1 on: April 26, 2010, 08:21:22 PM »
I have a 20moa base on my .308, it does give you a bit more vertical adjustment, well 20moa to be exact. We are talking 1k shooting an beyond not normal hunting ranges.

I believe the shim would go under the rear if you went with the shim method. Might wreak havoc with the screws and threads in your receiver. Might just be better off buying a 20moa base. You might look into Burris rings. Luvmy45 told me he was happy with some 20moa or 30moa rings/inserts that he had acquired. I think Barrett makes rings like this as well. The Barretts are way spendy, the Burris' not so much.
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Offline ida83704

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Re: 20 MOA base shims
« Reply #2 on: April 26, 2010, 08:22:47 PM »
What scope?  You may not need a sloped base.
The shim goes under the back of the base, not the front, and shimming is the least favorable solution.
The 22-250 punks out at 900-1000 yards with a 1 in 12 twist barrell, so your scope may be ok as is.
Any decent ring or base maker makes a good 20moa base: EGW, Night Force, Badger, Warne, etc.
Burris Signature Zee rings accomplish the same thing.

Sloped bases start at $40 and go up to $100ish



Offline adrewiske

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Re: 20 MOA base shims
« Reply #3 on: April 26, 2010, 08:59:26 PM »
I should have also included I would like to use it on my 7 rem mag also. I'll look into these companies and thanks for the insight!

Offline Bill, Idaho

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Re: 20 MOA base shims
« Reply #4 on: April 26, 2010, 09:25:03 PM »
A shim in that process will probably cause everything to be in a literal bind, stressing the scope tube, rings, and base. IF you need a canted base, buy one. Shims are not the right way to fix it.

Offline Nealio

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Re: 20 MOA base shims
« Reply #5 on: April 27, 2010, 09:54:18 AM »
Bill is correct.  The only way to do this properly would be to run the Burris Signature  rings which have an insert like Heim joint, which then allows the 2 rings to be mounted unevenly and still not put undue stress or torque on the scope tube..

http://www.burrisoptics.com/sigrings1.html#2



Offline fj40mojo

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Re: 20 MOA base shims
« Reply #6 on: April 27, 2010, 10:03:11 AM »
For $40-$60 you can get an EGW base with 0-20MOA built in.  I've heard conflicting reports about how well the Burris rings work but have no personal experience with them.
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Offline Nealio

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Re: 20 MOA base shims
« Reply #7 on: April 27, 2010, 01:36:24 PM »
For $40-$60 you can get an EGW base with 0-20MOA built in.  I've heard conflicting reports about how well the Burris rings work but have no personal experience with them.

My Dad and I run them.  Hard to say "how good" they work since I haven't ever mounted them on a purposely crooked rail and XRay'd the tube to see if it relieves stress.. :)
But I have taken the top part of the clamp off of 1 of the clamps (leaving the other tight) and my scope tube doesn't move.  I've seen tubes move a tiny bit (.005" maybe?) on some of my solid mounts when I do this..
 - Nealio

Offline Nomad

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Re: 20 MOA base shims
« Reply #8 on: April 27, 2010, 01:40:19 PM »
 Brownells has  shims that you can put under a single piece rail to shim to get the
right amount of height for your scope........

Offline mjmcmahon

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Re: 20 MOA base shims
« Reply #9 on: April 27, 2010, 01:44:50 PM »
For $40-$60 you can get an EGW base with 0-20MOA built in.  I've heard conflicting reports about how well the Burris rings work but have no personal experience with them.

I just ordered an EGW base and will be using Burris TAC rings with it...I'll report back later this week on how it all went together. :)

Offline adrewiske

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Re: 20 MOA base shims
« Reply #10 on: April 27, 2010, 01:57:00 PM »
Thanks, i was looking at burris's zee line and the tac line. I think i'm going to go with two bases, to prevent any undue stress and twisting to the chamber.

Online luvmy45

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Re: 20 MOA base shims
« Reply #11 on: April 27, 2010, 01:57:18 PM »
I run a 25MOA EGW base with Burris xTreme rings... no problems so far after about 2 years.

It's not Badger, but then again, neither is the price.
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Offline adrewiske

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Re: 20 MOA base shims
« Reply #12 on: April 29, 2010, 10:24:46 PM »
What are you shooting that you put a 25moa base on it. I want to order a 20moa base for my browning 7mm long action. I have some concerns with mounting a solid 1 piece base and the tension it could put on my action/scope. Or does that only matter if the holes were drilled on a friday by a drunken gunsmith?

Offline ida83704

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Re: 20 MOA base shims
« Reply #13 on: April 29, 2010, 10:43:11 PM »
luvmy45 is refering to/shoots a Savage 308 bolt gun, in addition to may others.

I personally don't worry about 1 piece bases tensioning the action.
Every Sniper-ery rifle the U.S. uses now has a 1 piece base.

My hunting rifle has 2 piece bases because I'm tired of cutting my fingers on the Picatinny rail when I jam shells into it.



Offline adrewiske

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Re: 20 MOA base shims
« Reply #14 on: April 29, 2010, 10:46:43 PM »
I agree on using two bases, but the EGW's are ones that are in my price range. With a 50mm objective lens should i get the standard 1/4" rings or do i need to go up to a 1/2" or higher to account for a bigger lens than what I previously had?

Offline ida83704

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Re: 20 MOA base shims
« Reply #15 on: April 29, 2010, 10:57:08 PM »
I've got an EGW base, works good.

1/2 rings will prob be too high.

Are you getting rings local? then get lows or 1/4's.  If they are too low, return them.
If you are internet buying the rings, 3/8 or medium is a safer bet.



Offline adrewiske

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Re: 20 MOA base shims
« Reply #16 on: April 29, 2010, 11:01:50 PM »
I was thinking/looking at Burris Extreme rings on SWFA's website. I didn't want to get the low ones and not have enough clearance between my scope and the barrel and have to go through the hassle of returning them. You think i'd be ok with the 1/4" rings then?

Offline ida83704

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Re: 20 MOA base shims
« Reply #17 on: April 29, 2010, 11:08:19 PM »
Cabelas in Boise carries the Burris Extreem rings.

Get the mediums (1/2) and see how they fit.(I don't think they have the 1/4's)
If they are too high and you have 1/4 gap between the scope and the barel, return the Cabelas and get the 1/4's at SWFA.

Offline adrewiske

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Re: 20 MOA base shims
« Reply #18 on: April 29, 2010, 11:12:47 PM »
Awesome, thanks! I will do just that!

Online luvmy45

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Re: 20 MOA base shims
« Reply #19 on: April 30, 2010, 08:31:16 AM »
Ida handing out some dandy advice... on the ring height, your barrel will probably be the deciding factor.

If you have a bull barrell, you may need the higher rings, if you have a hunting barrell you may get away with the lower rings.

I run the low rings on my set and the scope hovers just over the barrell, but is a SS 10 x 42 so a larger objective would call for the next ring height.

I bought the 25MOA base because it was available for the same price as the 20moa when I went to order. I wanted 1k + yards out of my gun, and the more MOA the merrier!  ;D

The one thing you should do when you get your scope is spin the knobs up and down all the way and write down exactly how much travel you have for elevation and windage. Once you get your zero, do it again and write down what how many click off the bottom your zero is. Then you will know excatly how much come up you have in your scope.

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Offline carharttfarmer

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Re: 20 MOA base shims
« Reply #20 on: April 30, 2010, 10:03:59 AM »
cabelas had a pair of medium xtr rings in the bargin cave last time i was there could save ya about 15 bucks

Offline ida83704

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Re: 20 MOA base shims
« Reply #21 on: April 30, 2010, 10:14:46 AM »
and the more MOA the merrier!  ;D

This is a very true statement!

Offline Lt Smoke

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Re: 20 MOA base shims
« Reply #22 on: May 02, 2010, 07:02:23 AM »
I bought a Cooper Model 22 in .308 from Cliff's a couple of years ago. I ordered a 20 MOA base with the rifle and a set of 30mm Burris Zee Rings. The mount is solid and I have had no worries with this set up. I believe if one starts with a solid foundation there will be less to go wrong in the future.

Offline adrewiske

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Re: 20 MOA base shims
« Reply #23 on: May 02, 2010, 04:53:24 PM »
So far i ordered a 20MOA EGW base and plan on getting the 30mm Burris extreme tactical rings. We'll see how that works out.