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Old July 5, 2020, 10:03 PM   #1
4V50 Gary
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Unertl 8x scopes

As used by the USMC in WW II, how well were they sealed? I don't think nitrogen filling was a thing at the time.
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Old July 7, 2020, 10:25 AM   #2
reynolds357
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Quote:
Originally Posted by 4V50 Gary View Post
As used by the USMC in WW II, how well were they sealed? I don't think nitrogen filling was a thing at the time.
I dont know. I have seen a couple of them. However they were sealed all those many years ago, they obviously were no longer sealed.
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Old July 7, 2020, 10:56 AM   #3
jcj54
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Unertl external adjust scopes

the vast majority of Unertl external adjust scopes such as the WW2 USMC 8X were not sealed or nitrogen filled. Unertl internal adjust scopes are a different story. I own an early Unertl 11/2" 10X external adjust target scope, s n 172. It is not sealed....

Last edited by jcj54; July 7, 2020 at 01:13 PM.
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Old July 7, 2020, 01:03 PM   #4
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Thanks jcj54.
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Old July 7, 2020, 01:16 PM   #5
Bart B.
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Far as I know, none of those older Fecker, Litchert, Lyman, deSimone and Unertl externally adjusted scopes were gas filled.

Properly mounted, they're the only scopes that all of them can guarantee exactly 1/4 inch, mil, or MOA @ 100 yards per click. No internally adjusted scope can do that.

Last edited by Bart B.; July 7, 2020 at 03:20 PM.
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Old July 7, 2020, 05:21 PM   #6
jcj54
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external adjust scopes

Fun fact, when bases are mounted at the correct 7.2" center to center spacing the amount the click moves the scope for 1/4" at 100 yards is .0005".
And it is repeatable all day long.
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Old July 7, 2020, 05:42 PM   #7
Bart B.
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Only problem with these scopes is the barrel vibration frequencies are different without the front mount on the barrel when metallic sights are used in long range matches. Bullets won't leave at the best angle on the bore axis upswing to compensate for velocity spread.

All of which is why internally adjusted scopes by Weaver and Unertl began replacing them in the 1980's for use in highpower long range matches.
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Old July 7, 2020, 06:45 PM   #8
Bart B.
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Quote:
Fun fact, when bases are mounted at the correct 7.2" center to center spacing the amount the click moves the scope for 1/4" at 100 yards is .0005".
Both those externally adjusted scopes and target rear aperture rear sights have 40 tpi leade screws. Rear scope mount knobs had 50 clicks per turn, target rear sight knobs used 12 clicks based on the standard sight radius of 30 inches.

When I had a 1.5" Unertl 20X scope, I mounted the rear base on the receiver bridge 10.8" back from the front base. That gave 1/6th MOA change per click. Most important was the LOS adjustments were much easier to reach and prone position stayed more repeatable between adjustments.

Last edited by Bart B.; July 8, 2020 at 07:03 AM.
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Old July 7, 2020, 11:25 PM   #9
Jim Watson
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Unertl made "bridge bases" that kept the target scope off the barrel.

Remington made their own external adjustment target scope that put both bases on the receiver of a 40X.

Last edited by Jim Watson; July 7, 2020 at 11:31 PM.
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Old July 8, 2020, 10:52 AM   #10
4V50 Gary
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Found these on the Malcom which is a copy of the Unertl. User manual and Recoil Spring Assembly instructions:

https://cdn.shopify.com/s/files/1/17...66545434398741
https://cdn.shopify.com/s/files/1/17...66545434398741
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Old July 9, 2020, 06:19 AM   #11
4V50 Gary
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For the visually or audio oriented, the dismounting of the spring is covered here:
https://youtu.be/z4hWW5ssoWQ
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Old July 26, 2020, 02:34 PM   #12
langenc
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Parsons scope service used to do a wonderful job on Unertls. I dont know if they are still in business.

No one seems to know how to do that or wants to learn. There is a good demand for someone qualified to tuneup scopes.

Parsons was located NW of Cincinnati, OH.
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Old July 26, 2020, 05:03 PM   #13
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Quote:
Parsons scope service used to do a wonderful job on Unertls. I dont know if they are still in business
.

Parsons is still in business:

http://parsonsscopeservice.com/services.html
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