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Scopes

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15 September 2003, 07:47
Chuck F
Scopes
I'm looking to purchase a scope. Looking at different catalogs and the same scope, I see it advertised as 3-9x 40mm obj.48mm and 3-9x 40mm. What does the 40mm and 48mm mean?
15 September 2003, 07:58
Bigdaddytacp
quote:
Originally posted by Chuck F:
I'm looking to purchase a scope. Looking at different catalogs and the same scope, I see it advertised as 3-9x 40mm obj.48mm and 3-9x 40mm. What does the 40mm and 48mm mean?
The larger number means the size of the front'objective of the scope......some measure the actual lens size/diameter and others it is the outside of the scope body......standard full size objectives start at 40mm,42,44,50,56mm.....and with all else equal the larger lens opening allows more light to enter the scope to pass thru the lens....BUT it also means the scope is larger/heavier? and has to be mounted higher using higher rings to let the larger objective clear the barrel......this can be uncomfortable for some people and non high rise/monte carlo type stocks and lets heavy recoil guns get a "running start" at your cheek......for early dawn/dusk or where legal night hunting can use the large objectives and the high power target/varmint scopes can make use of the extra light admitted by the larger objective lens in the upper powers......AGAIN this is with all else equal....a high quality multi coated smaller lens scope might be/is often clearer and brighter than a large lower quality single coated/or multicoated lens group scope......HTH..good luck and good shooting!!
15 September 2003, 08:55
Chuck F
Thanks for your help. Then bigger isn't always better.

Chuck
15 September 2003, 09:10
KurtC
A lot of scopes intended for the European market will list two measurements for the objective. The smaller one is the actual diameter of the objective lens, and the larger one is the diameter of the housing around the objective lens. This outer measurement is furnished because on a "claw" mount the front ring goes around the end of the scope, not the tube.