$20.00

The devil is in the detail

  • Condition:
  • Make:A book by Samuel B. Mann
  • Model:'LIGHT AT THE START OF THE TUNNEL - Are rifle scopes off the rails?'

Private User

Seller Type: Private User
Licence # 431-725-90B
Location: ESSENDON NORTH, VIC, 3041
Phone #: *** click to reveal ***
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Description:

If you patent something, it pays to mention everything involved in the mechanism, even crutches and bandages needed to allow the invention to work.

Why? Because if you leave the 'crutches' out someone might patent them, forcing you to pay to produce them.

When Weaver and Kollmorgen/Redfield patented 'constantly centred reticles' 65 years ago they knew there was a problem, causing them to say the new scopes needed a diaphragm or field stop - but to fudge its real purpose. Some scopes with a 'constantly centred reticle' have needed the field stop just to block out vision that might reveal it is not centred at all - but that was not the pioneers' main worry.

They mentioned suppression of stray light but not that the new invention was more subject to it than previous designs. Field stops had previously been used in scopes for aesthetic reasons but rarely so constricting and never for the same contingency.

As an example of the optical cost, Leupold's 4x scopes' field of view shrank from 35 feet at 100 yards to 30 feet when they finally surrendered to the new decadence, with no commensurate lengthening of eye relief.

Though lens coatings and waterproofness have improved since the 1950s, the tunnel vision from that field stop still blights the design.

'LIGHT AT THE START OF THE TUNNEL - Are rifle scopes off the rails?' traces riflescopes' descent from the golden age following WWII, down to the marketers' carnival of today. The book and its updates explain this and other exhibits in the chamber of scope horrors.

The $20 special includes an extra 16 pages to be emailed; other options available on request.

The first text fragment h/w is from Weaver's patent US-2949816* filed in 1956; the second is from Redfield's 1962 US3161716A; the drawing from Kollmorgen/Redfield's 1956 patent US2955512A shows the narrow field stop (50).


*The hyphen helps it google for some reason.

Date Listed: 20/07/2021

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