40mm or 50mm scope

[NDHunter]

Hahaha!! Well that's a no brainer! You hunt Wyoming in the fall. Duh! And then when I am using my 50mm leupold scope and you're using your 40mm scope and I get the animal, you can watch me pack it out on my horse! Hahaha

Sorry Jen, doesn't look like I'll be going to Wyoming this year. Hopefully will be going to New Mexico though for elk
I'll be buying another point for Wyoming this year and hope to go there in another year or two. And with my 40mm scope to boot!!

Is that what you have though is a 50mm? Do you put it in a scabbard at all? I've got an Eberlestock J34 and last year when I had my rifle in the scabbard, it was kind of a tight fit even with a 40mm scope so I'm wondering if a 50mm will be too tight.

[ChadH]

Bitterroot Bulls gave you some excellent information. The exit pupil is most if not all the equation. One thing that always seems to come into play to me is the tube diameter (1 inch or 30 mm) I personally can't really tell the difference between a 40mm obj with a 30mm tube, and a 50 mm objective with a 30mm tube in practical hunting conditions. I do however find a 40mm with a 30 mm tube brighter than a 50 mm obj with a 1 inch tube. I have no idea the math behind that because exit pupil doesn't really factor in the tube diameter. I always thought of it this way, the limitng factor at some point would have to be the tube diameter. A bigger objective would be fine, but the light still has to pass through a 1 inch tube to get to your eye, or you could give it a bigger hole by going to a 30mm tube. My mind could easily be playing tricks on me though (not an uncommon occurance ). In the end a 40mm with a 30mm tube just mounts up better to me and the check weld is way more comfortable and consistant with the lower Talley rings it lets me use. Someone mentioned the newer Leupolds have an objective end shaped to allow you to mount it lower and that might well be the answer, I haven't tried that yet.

[Bitterroot Bulls]

Tube diameter comes up a lot. It does NOT affect brightness!! Ask any optical engineer - I have. The light doesn't fill up the tube on its way through the scope. It follows a narrow path through the erector assembly. The advantage of a larger tube is twofold:

1. Larger tubes have some strength advantages.
2. Larger tubes allow for more internal adjustment (more room for the erector assembly to move).

These are the reasons that the high end long-range tactical scopes have huge 34mm and 35mm tube diamters, not brightness.

[ChadH]

Tube diameter comes up a lot. It does NOT affect brightness!! Ask any optical engineer - I have. The light doesn't fill up the tube on its way through the scope. It follows a narrow path through the erector assembly. The advantage of a larger tube is twofold:

1. Larger tubes have some strength advantages.
2. Larger tubes allow for more internal adjustment (more room for the erector assembly to move).

These are the reasons that the high end long-range tactical scopes have huge 34mm and 35mm tube diamters, not brightness.

I kind of figured as much... like I said, I am probably crazy (my wife would tell you that is for sure the case). It just always seemed to me that the my scopes with a 30mm tube were brighter, but then I should probably figure in the fact that those a better scopes to begin with. I do haowever really like using low rings, and the last time I was buying a scope the new Leupold design on the Objective end wasn't available, so I always stayed away from 50MM tubes. That is probably personal preferance though.

[Bitterroot Bulls]

You're not crazy Chad, we see what we see. The bigger-tube-brighter thing is a common misconception that was actually started by riflescope marketers in their advertising. Of course, they were full of it, and it did sell scopes.

If you want a bright scope in low light, just get a big enough exit pupil. a 4X32 (8mm exit pupil) scope will be noticeably brighter than a 4-14X50 scope on 15x (3.5mm exit pupil) of similar quality. Now the big scope will get brighter as you dial down the magnification, of course.