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MOA question. (Read 5339 times)
rgchristensen
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Re: MOA question.
Reply #15 -
May 19
th
, 2018 at 2:37am
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100 yd. is 3600 inches. 7.2", a common block spacing, is 1/500th (or 2/1000th) of that. So every 0.002" on the block height is close to 1 MOA.
Don't bend or spring the scope. Likely won't damage it, but it may very well not STAY where it is put, from shot to shot.
CHRIS
RGChristensen
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Schuetzenmiester
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Re: MOA question.
Reply #16 -
May 19
th
, 2018 at 4:43am
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rgchristensen wrote
on May 19
th
, 2018 at 2:37am:
100 yd. is 3600 inches. 7.2", a common block spacing, is 1/500th (or 2/1000th) of that. So every 0.002" on the block height is close to 1 MOA.
Don't bend or spring the scope. Likely won't damage it, but it may very well not STAY where it is put, from shot to shot.
CHRIS
RGChristensen
Yeah! Looks like my decimal point slipped a cog
"some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence
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boats
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Re: MOA question.
Reply #17 -
May 19
th
, 2018 at 6:12am
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I think his desired outfit is a modern Leupold. Ring spacing shorter than externals the formula the same though. The hole spacing for ring to ring length flexible to a point. Short space it needs very little movement to alter POI.
Modern scopes are a tube within a tube, when you raise the rear not the front you are bending the external tube which acts the same as the ring mount in a external. Internal scope tube is not bent. However when installing internal adjustment scopes I lap rings with a scope sized bar.
Boats
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Cat_Whisperer
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Re: MOA question.
Reply #18 -
May 19
th
, 2018 at 6:54am
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Lapping the rings will show you where the misalignment, if any, is.
Cat Whisperer (trk)
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boats
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Re: MOA question.
Reply #19 -
May 19
th
, 2018 at 7:59am
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Cats right start lapping misaligned rings show up right away. My experience scopes mounted without block shims just as likely to be mis aligned as a shimmed block.
Boats
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Hey Joe
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Re: MOA question.
Reply #20 -
May 19
th
, 2018 at 8:21am
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Finest selection of shim stock is a Harbor Freight feeler gage. Many sizes, all labeled at about $ .99
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JLouis
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Re: MOA question.
Reply #21 -
May 19
th
, 2018 at 12:37pm
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Burris Signature Rings with the insert kit might be the easiest approach..
JLouis
" It Is Better To Now Have Been A Has Been Than A Never Was Or A Wanna Be "
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BudHyett
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Re: MOA question.
Reply #22 -
May 20
th
, 2018 at 9:50pm
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I have two CPA 44 1/2's and use Frank Russell's base to adapt the external adjustment scope bases to an internal adjustment scope. This base fits on the external scope blocks and has a Weaver base on top for Weaver rings. The scope base as bought was nearly centered when swapping barrels. The point of impact was always predictable.
I use the Burris Signature Zee rings to be able to further refine the scope to be centered in adjustment at 200 yards. Swapping from the .32-20 barrel to the .25-20 on each rifle shows an eighteen inch difference in impact at 200 yards and that differential had to be moderated. That is the use of the Burris rings and setting a midpoint to enable the swap between barrels.
It is now easy to switch scopes from internal adjustment to external adjustment by just removing the base. In this manner, a person can shoot Traditional classes, ASSRA open classes, ISSA classes and CBA Plain Base class with one rifle.
Country boy from Illinois living in the magical Pacific Northwest
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bucksnort
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Re: MOA question.
Reply #23 -
May 22
nd
, 2018 at 2:50pm
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Bud, you shot next to me in Saturday's match.
Currently, I only own one CPA rifle. It is a .32-20CPA and I first mounted a Weaver T-36 scope on it. I then tried to experiment with mounting a Leupold Competition scope on it. This scope ran out of elevation for shooting at 200-yds. I'm now going to try shimming the base. When I get a good height, I will have and EGW mount cut/drilled to my specs.
It appears that any of the external adjustable scopes having enough power and being in decent condition are scarce (to say the least). ED
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RayH
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Re: MOA question.
Reply #24 -
May 22
nd
, 2018 at 4:10pm
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Bucksnort,
You and I are working with the same stuff. #1 - I have tried numerous scopes and am 100% satisfied with my Weaver T-36 on my CPA in .32-20CPA. #2 - I use the Leupold 45 Competition on my CPA 22LR RF set up with BR stock & forend (same as the .32). I chose the 45 only for increased magnification to enable me to better spot my point of impact. Honestly, I don't know that it's any better for me than the Weaver T-36. I plan to do more testing with the Weaver.
Both my internally adjustable scopes are set up in Burris Signature rings. I take plenty of time with the installation. The scope is set at it's center for both vertical and horizontal adjustment. I then work with the Burris inserts to achieve my chosen point of impact. Since I shoot at both 100 yds. and 200 yds., I install the scope so that vertical is dead on and horizontal is on center bull at 140 yards. It's pretty time consuming, but with this set up, it requires minimum horizontal clicks from the scopes center of adjustment range. I feel this is mechanically least stressful for the scope and it gives me plenty of adjustment for adverse conditions. Most important - the Burris signature inserts and take your time to set it up precisely. Hope this helps.
In GOD We Trust
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JLouis
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Re: MOA question.
Reply #25 -
May 22
nd
, 2018 at 6:05pm
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Agree totally with Ray and like he said take your time with the inserts they do require a little time and effort but are indeed well worth it. Not only do they not put any stress on the scope tube body they also do away with having to lap the more typical rings being used and the inserts also will not mar the scope and another real big plus.
JLouis
" It Is Better To Now Have Been A Has Been Than A Never Was Or A Wanna Be "
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