I'd pass on 50mm unless you are going to be doing a lot of shooting in low light situations. In general, the larger the front objective, the more difficult it is for the manufacturer to accurately grind the glass. Therefore, the cost goes up. The benefit of larger glass is to gather light in low light conditions. Anything with a 3mm exit pupil is ok. 40 divided by 9 is 4.4. So a 40mm objective in 9x power is plenty. You could go as low as the 27mm front objective, but I don't believe anyone makes one that small in 9x.

 

In addition to what has been said above, the larger diameter objective also reduces the "depth of field". That is the distance in front of and behind the actual distance that the scope is focused on. With fixed focus scopes (as are all without adjustable objectives) the target would be out of focus in varing degrees if not at the focus distance of about 100 to 150 yds (the average fixed focus distances for most scopes). The larger the diameter of the objective the more that depth of field (focus) is reduced.

In America where hunting is limited to basically daylight hours it makes little sense to use scopes with large objectives. With the difficulty in making sharp large objecive lenses, and the loss of image quality at distances other than the focus distance, large objective scopes are all sales hype. Go for the "40".

LDBennett

 

I learn something new ever day here. Sometimes without ever even asking!

Chris

 

I like brighter scopes -- It probably does not make any difference which one you choose but I have been known to "target shoot" at night.
________
Help Love

 

I will warn you about using centerfire scopes on a rimfire. Typical rimfire shooting ranges are in the 50 yard range. Up here where we have seasons indoors at 50 ft is the norm for almost half the year. A scope focused at 100 or 150 yards is going to be a pain to use at shorter distances. First you have the problem that the target and crosshairs cannot both be in focus. Second your eye is being forced to compensate for the incorrect focus. Third you have parallax errors where the crosshairs centered on the bull do not mean the rifle is pointing at the same spot. For a deer sized animal the error is not significant but for a 0.1" bull it is huge. For a 22LR I would get a scope with an adjustable objective capable of focus to 10 yards or 50 feet.

Before you get a scope that is inappropriate for a 22LR check out some of the scopes that are:

Leupold 3-9x33EFR (AO)
Simmons 22Mag 3-9x32AO ($60 at Natchezss on clearance)

I think Bushnell / Tasco, Burris and other makers have scopes like this also. They are easier to mount, are plenty bright, and are comfortable to use for long shooting sessions.

 

I agree with what Brookie has stated. I believe that a 50mm scope is going to be problematic for the reasons stated above in earlier posts, plus getting it mounted might be tough, and it's going to look rather odd on a rifle that small as well.

I have a Bushnell Trophy series 4-12X40 AO scope and it works great for me. I wouldn't want anything bigger.

 

I have a Bushnell 72-0039 on my American 22lr. This is a 3-9x32 AO. It is gloss black, which matches the gun's polished blue well. It has target turrets. It is primarily an airgun scope, and is very sharp and bright. The scope comes with rings, however you WILL need a different set of HIGH rings to clear the bolt handle. This is due to the large ocular lense housing ( rear ). Also, this scope is a very good buy at about $65. My gun will shoot MOA or better consistently with CCI Velocitor at 100 yards.

 

First off let me say this, if this is a hunting rifle then the scope in question, either the 40mm or 50mm either one will work. If you go down to the scope, rings and mounts section you will find several very informative threads dealing with parallax and focus. The focus of a scope can be set to your individual eye, if the crosshairs appear to be out of focus you can cover the front objective with a tissue, something that is white and will let light pass through, or point the rifle at a solid white wall in a well light room. And adjust the rear eye piece until the crosshairs are focused for your eye. Now not all scopes have that adjustment ring on the rear eye piece, on these scopes you have to screw the whole eye piece in or out to focus it for you.

While it is true the parallax on a scope set for centerfire rifles is set at 100yrds, shotgun scopes are set at 75yrds and rimfire scopes are set at 50yrds. This parallax setting has nothing to do with the focus. And in a low power hunting scope, parallax is not an issue anyway. The difference between the point of aim and the point of impact will only be a fraction of an inch due to parallax, and if your eye is lined up looking straight through the center of the scope parallax is not an issue anyway. And for a hunting rifle having a difference of a 1/4" between POA and POI just doesnt matter.

I own three Rifleman scopes, 2-7X33, 3-9X40 and the 3-9X50. The optics in these scopes are as clear as any of the other leupold scopes. Even in the 50mm the field of view is clear right out to the edge of the objective. And as far as focusing at close range, any scope including rimfire scopes become blury at very close range. These scopes on 3X have a clear focus down to around 15 feet, and on 9X are clear down to around 25 feet.

Now if you do a lot of short range target shooting, then an AO scope will be worth your time. But if this rifle is a pirmary hunting rifle and occasionaly for informal target shooting, the scopes your asking about will be fine and will work very well. To me an AO scope on a smallgame rifle is a pain in the butt, because your constantly have to keep one hand on the AO ring to adjust it just so you can focus on the game.

 

The guys above have covered the optical issues well.
There is VERY little need, if any, for a 3-9X scope with a 50mm objective on a 22 Rimfire rifle. Maybe it was mentioned, but a 50 mm objective drives you to a higher mounting of the scope on the rifle due to the larger bell. This means your head will be placed higher on the stock to see thru the scope.. Not good. The 50mm's do not look nearly as good as a 40 or 44mm objective mounted on a rifle. Over the years, I've gotten rid of all scopes with objectives larger than 44mm, except for benchrest rifles where I kept some of the big objective scopes because I had them, not because they were optically superior to smaller ones. I think LD Bennett drives that point home very well. Brookie mentions another very important point with scopes for 22's also.
I get sufficinet exit pupil from smaller objectives, so there is absolutely no need for a 50mm, or larger. Depth of field is very important for me.
Don

 

I currently have a VXI 3-9x50 on my CZ-452 Style which I get on really well with, however I do a lot of lamping and shooting in low light conditions so the extra light it lets in really helps. The previous scope that I used had a 40mm scope on which worked well during the day and for paper punching, but I don't think that I'd switch back now because it just wasn't as good at night.

So basically if your not going to be shooting at or after dusk go with the 40mm, otherwise I think the extra light gathering of the 50mm is worth having.

Stephen

 

I agee with all said above with one minor exception. Paralax error is a direct function of the objectives image not being focused on the crosshairs.

A scope is two systems: an objective section that focus the target on the image plane of the crosshairs and a eyepiece system that focuses the eye from the other end of the scope on the image plane of the crosshairs.

The objective system in a non-Adjustable Objective scope is preset to be in focus at 100-150 yds for hunting centerfire scopes, perhaps 75 yds for shotgun scopes and perhaps 50 yds for 22 scopes. But it is in sharp focus at only that one distance. Any other distances the image does not fall on the crosshairs but at some other point in front of or behind that plane. When you move your eye off center of the scope the cross hairs will apprear to move on the target. That is paralax error. It can be zero if you keep you eye in the center of the scope and a measurable amount if your eye is off center. How much depends on the difference in the preset focus and the targets actual distance and the magnification of the scope. For target scopes paralax is bad and that is why so many high power target scopes include Adjustable Objectives--to focus the objective system on the target and eliminate paralax errors.

Paralax error is easy to detect. Fix the gun on bags, centered on the target. Without moving the gun move your head back and forth, viewing the target from one edge of the scope to the other. You'll observe the crosshairs apparently moving on the target. Where's the bullet going to go. To the place on the target where your eye is centered in the scope. At the correctly focused distance there will be no movement of the crosshairs on the target whether you are centered or not.

Your eye can compensate for the two image planes when a scope is used at distances other than the correct paralax corrected distances. It moves its focus back and forth between the image of the crosshairs and the image of the target but it is very tiring for the eye if the difference in planes is great and at some distances it is impossible and the image goes fuzzy.

I never buy scopes unless they have AO but I only target shoot. For hunting scopes (3 to 9X power) the AO feature is not necessary. For target work you must have AO or only shoot at the paralax correct distance. I like the Bushnell Trophy 4 to12X AO scopes as they can be used for anything: hunting at low powers and adjusted to 100 to 150 yds and 22 target shooting set at higher powers indoors at 50 ft and anything in between. I have many scopes from Burris to Leopold to Tasco and I find this Bushnell scope the most scope for the least money.

LDBennett

 

I found another reason to use the 50mm objective. My wife. She cannot focus well enough to use a scope with less than a 5mm exit pupil. I've tried just about everything to get her to settle down with an exit pupil below 5mm, even to the point of having factory reps help her, to no avail. She does target shoot, and the higher magnification does help her. So, we settled on using a 50-52mm objective. It lets her go up to 10x without difficulty.

It doesn't appear to be a correctable condition, according to the optometrist. I believe, and he mentioned, that it may have a psychological factor involved, perhaps an incipient claustrophobia, but it's just the way that it is. Believe me, it's a lot cheaper to get the larger objective than it is to deal with the medical community.