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Old 02-05-2010, 04:08 PM
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DavidU (Dave)
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Join Date: Jul 2007
Location: melbourne
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Caps with 2 holes are used for focusing
http://www.billyard-ink.com/Hartmann.shtml
Caps with one larger hole off set from the centre is to stop down a scopes aperture (ie: turning a 12" f5 into a 6" f12).
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