I am going to get a new scope for a my coues gun. The gun is custom 7mm mag built on an old mauser action. I have decided on one of the new Nikon Monarchs, with side focus, in 4x16. These scopes are getting great reviews, and they are relatively inexpensive.
One thing I have not been able to decide on is whether to get the 42mm or 50mm objective. Here are the specifications for both scopes:
Monarch 4-16x42SF
Actual Magnification 4x-16x
Effective Objective Diameter 42mm
Exit Pupil (mm) 10.5-2.6
Eye Relief (in.) 4.0 -3.7
FOV at 100 yds (ft.) 25.2-6.3
Tube Diameter 1 in (25.4mm)
Objective O.D. (mm/in) 49.3/1.94
Eyepiece O.D. (mm/in) 44.0/1.73
Length (in) 13.5
Weight (oz) 19.0
Adjustment Graduation (1 click) 1/4 MOA
Max Internal Adjustment 40 MOA
Parallax setting (yds) 50 - ∞
Monarch 4-16x50SF
Actual Magnification 4x-16x
Effective Objective Diameter 50mm
Exit Pupil (mm) 12.5-3.1
Eye Relief (in.) 4.0-3.7
FOV at 100 yds (ft.) 25.2-6.3
Tube Diameter 1 in. (25.4mm)
Objective O.D. (mm/in) 57.3/2.26
Eyepiece O.D. (mm/in) 44/1.73
Length (in) 14.7
Weight (oz) 19.4
Adjustment Graduation (1 click) 1/4 MOA
Max Internal Adjustment 40 MOA
Parallax setting (yds) 50 - ∞
I don't really know a lot about scopes, but I think that the size of the exit pupil can make a big difference. At 16 power the 50 mm has a 3.1mm exit pupil, while the 42mm has a 2.6mm exit pupil.
My question is-- how much of a difference would that make in a low light situation?
The downsides to the 50mm is extra weight and length. But In this case it does not seem like much of a difference-- the 50mm is one inch longer, but only .4 oz heavier. That does not seem like much.
The other downside is that I might need higher rings. I am not sure how much of a negative that really is. Does it really matter if the scope is higher off the gun?
Any advice would be appreciated.
Thanks
Jared
