Would it be worth $30 to get a 40mm diameter scope instead of a 32mm diameter scope to put on a rimfire? I feel that it would be but I'm inexperienced in scopes to really know. The $30 isn't a big hit, but if I'm not getting anything for it, then I'm not going to bother.
40mm or 32mm for rimfire
- Thread starter MJRW
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I switched out a VXIII-3.5-10x40 Leupold for a 2-7x28mm Leupold Rimfire and have enjoyed it so much more. The gun carries better and truly, I have had more fun with it. It seems to just fit the gun better! It has been a blast for hunting on a 10/22!
Dr. Tad Hussein Winslow
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Objective lens size
It depends highly upon the scope's magnification range (which in turn depends upon the USE/ROLE of the rifle), and also, to a lesser extent, depends upon the quality of the glass and whether or not you'll use it in low light conditions (which also depends upon USE/ROLE).
What's the USE of the gun (hunting - what, or targets, or plinking), and thus what magnification range? The exit pupil size is the key factor here.
It depends highly upon the scope's magnification range (which in turn depends upon the USE/ROLE of the rifle), and also, to a lesser extent, depends upon the quality of the glass and whether or not you'll use it in low light conditions (which also depends upon USE/ROLE).
What's the USE of the gun (hunting - what, or targets, or plinking), and thus what magnification range? The exit pupil size is the key factor here.
SimpleIsGood229
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Remember this: better a cheap rifle with good, quality glass than vice-versa. 
Here's the deal. A bigger lens can transmit more light, (up to a point), and gives you a wider field of view. It also weighs more and requires you to mount the scope 4mm higher in order to accomodate the larger lens. Also the bigger the lens, the more potential for parallax.
As far as light transmission goes, you get as much light as you can see if the lens diameter is 7 or more times the magnification. This has to do with the maximum size of a dilated human pupil. So with a 3-9x40 scope you'll get your maximum light transmission if your scope is set to just under 6x or lower. With a 3-9x32 you have to set it down to around 4.5x to get the same light transmission you would get at 6x with the bigger lens.
A bigger lens also can increase parallax. This is when the crosshairs shift slightly when you move your head side to side or up and down. I find that this only really comes into effect when you're trying to do precision shooting and if that's the case then you want a parallax adjustable scope. In any event the practical difference in parallax between a 32mm and a 40mm scope on a plinking or hunting rifle will be minimal.
As far as light transmission goes, you get as much light as you can see if the lens diameter is 7 or more times the magnification. This has to do with the maximum size of a dilated human pupil. So with a 3-9x40 scope you'll get your maximum light transmission if your scope is set to just under 6x or lower. With a 3-9x32 you have to set it down to around 4.5x to get the same light transmission you would get at 6x with the bigger lens.
A bigger lens also can increase parallax. This is when the crosshairs shift slightly when you move your head side to side or up and down. I find that this only really comes into effect when you're trying to do precision shooting and if that's the case then you want a parallax adjustable scope. In any event the practical difference in parallax between a 32mm and a 40mm scope on a plinking or hunting rifle will be minimal.
elmerfudd,
Us old guys can't even use the whole 7mms. That figure is for youngsters, and your pupil only gets that big in full dark. For most legal shooting, all you need is 4mm. With good glass, a smaller objective may even gather light better than a big objective with cheap glass.
MJRW, what scopes are you considering?
Us old guys can't even use the whole 7mms. That figure is for youngsters, and your pupil only gets that big in full dark. For most legal shooting, all you need is 4mm. With good glass, a smaller objective may even gather light better than a big objective with cheap glass.
MJRW, what scopes are you considering?
freakshow10mm
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HAHAHA! I thought you meant caliber. I was thinking "damn that's a big ass rimfire."
Nikons, in my experience, have extremely good glass for the money. The one fault they have is their extremely poor customer service. If you ever have problems with one of their scopes (which is admittedly rare) you're better off buying a new one than trying to get service.
I'd buy that scope without hesitation. It pays to shop around, as price varies widely.
I'd buy that scope without hesitation. It pays to shop around, as price varies widely.
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