IR Filters: Sniperscopes - Help Needed

We are attempting to identify all of the IR filters used with the Sniperscopes Models M1, M2, and M3. What we know of so far are shown and described below. Sorry the pics aren't better but they are utilitarian as opposed to display pics.

If you have something different please add to this thread with a description of what you have using the info format used for the 7 filters below. A pic or two of the markings would also be greatly appreciated but isn't a requirement.

Thanks much

Jim

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Our Reference designation: A-1529

Material:
     glass
IR Coating:
     on the side facing the bulb
Raised rim around outer edge:
     Yes
Filter Markings & Method(s):
     a) THIS SIDE OUT A-1529, cast with glass
     b) 918 crossed out w/ S and 919 etched in glass
Gasket Markings:
     a) N-677



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Our Reference designation: Kopp Glass

Material:
     glass
IR Coating:
     on the side facing the bulb
Raised rim around outer edge:
     Yes
Filter Markings & Method(s):
     a) THIS SIDE OUT, white letters on glass
     b) KOPP GLASS, cast w/glass on rim
     c) 5/23 - 100, etched on rim
     d) 5 15/32 D, cast w/glass on rim
Gasket Markings:
     a) N-677



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Our Reference designation: ES

Material:
     glass
IR Coating:
     sandwiched between 2 pieces of glass
Raised rim around outer edge:
     No
Filter Markings & Method(s):
     unmarked
Gasket Markings:
     a) N-677
     b) D-557
     c) ES



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Our Reference designation: AO

Material:
     glass
IR Coating:
     on the side facing the bulb
Raised rim around outer edge:
     Yes
Filter Markings & Method(s):
     a) THIS SIDE OUT, cast with glass
     b) 8247-29-1, cast with glass
Gasket Markings:
     none

Note: sealed in package marked American Optical, commonly found on M3 scopes mfg by American Optical



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Our Reference designation: GB

Material:
     glass
IR Coating:
     unknown
Raised rim around outer edge:
     Yes, but barely
Filter Markings & Method(s):
     a) THIS SIDE OUT, cast with glass
     b) G.B. INC., cast with glass rim, located on side facing light
Gasket Markings:
     none
Notes: commonly found on M3 scopes mfg by Capehart-Farnsworth



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Our Reference designation: 8247-1x

Material:
     glass
IR Coating:
     on the side facing the bulb
Raised rim around outer edge:
     Yes
Filter Markings & Method(s):
     a) THIS SIDE OUT, cast with glass
Gasket Markings:
     a) 8247-29-2



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Our Reference designation: 8247-2x

Material:
     glass
IR Coating:
     on the side facing the bulb
Raised rim around outer edge:
     Yes
Filter Markings & Method(s):
     a) THIS SIDE OUT, cast with glass
     b) 8247-29-1, cast with glass
Gasket Markings:
     a) 8247-29-2



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Edited by sleeplessnashadow - Jan 18 2021 at 10:34am