sjpitts Report post Posted January 10, 2009 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 Share this post Link to post Share on other sites
