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Plus-20moa scope rail |
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glockpacker
Optics GrassHopper Joined: September/24/2005 Location: United States Status: Offline Points: 21 |
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Posted: July/17/2007 at 08:09 |
I understand that the elevation adjustments on a scope start generally in the middle of their range. That gives you a lot of down-elevation adjustment that is unuseable. That also gives you a relatively limited amount of up-elevation adjustment available to use.
So then you install a +20 moa scope rail: Then your 100-yard zero is down in that lower-elevation area that was unuseable before, and your up-elevation can go all the way to 1,000 yards or more.
Does it degrade the performance of the scope at all to make this change?
Is there anything I'm missing here? |
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Eric of Fort Lauderdale
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Dale Clifford
Optics Jedi Knight Joined: July/04/2004 Location: United States Status: Offline Points: 5087 |
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the better part of the image quality is in the center and degrades towards the edges, some scopes are worse than others of course.. some long range scopes already have this in consideration so that when dialing in 20 moa the degradation is not as severe, and of course these scopes are not centered mechanically but offset. with a 20 moa for example yes your ordinary zero would be 20 moa elevation. or usually 1 full turn off. if your doing a lot of shooting at 1000 yd, cranking down to 100 or back 1 full turn causes degradation and how much depends of the scope-- sometimes its not very muchthe 1000 yd scope I use has 18 moa hold over just in the reticle and with a 300 yd zero is pretty dead on. the 18 moa dot is however at the bottom and some fuzzies are still there. thus no 20 cant rail is needed as adding back 18 moa clicks recenters the central hold over. |
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bart
Optics GrassHopper Joined: July/15/2007 Location: United States Status: Offline Points: 11 |
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Let me get this straight, say I had a scope that had 50 moa adjustment then only 25 moa would be usable if I had it zeroed in the center of the scope. Now if I had a 20 moa scope base then I would only have 5 moa left for adjustment down, but would have 45 moa up. Now would the burris rings with the inserts be able to do the same thing?
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Dale Clifford
Optics Jedi Knight Joined: July/04/2004 Location: United States Status: Offline Points: 5087 |
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burris inserts offset the optical axis just like a canted base. if your scope is mechanically centered and in this case optically centered-- the 20 min. cant would point the axis down but to come up to a 100 yd zero would take 20 moa and leave you 5 left. how could one push the front of the scope down and have the clicks stay the same?
if the limitation in overall travel were not a factor why would the 20 moa cant had ever been invented? Edited by Dale Clifford |
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