Rifle Scopes: 50mm vs. 40mm profile?

K

Kirk_Ferentz

Joined
Feb 16, 2010
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589
Thanks to all of you who chimed in on my other scope post. A lot of great reviews and info. I'm close to a decision, pending a few specific questions. The biggest one is whether I should opt for the bigger 50mm objective lens, which is going to bring in some much-needed light around dawn and dusk, or stick with the more conventional 40mm lens.

It sounds like the major reason that I might NOT to go with the 50mm lens is that it might raise the scope beyond the comfortable eye level. I'm thinking that it is also going to make the rifle/scope more combersome.

Anyone familiar with both types of scopes (or just the 50mm I suppose) and have any opinion on whether the extra height causes any problem?

One solution that I have been toying with is to get one of the "knotched" 50mm leupolds that wraps around the barrel and has a lower profile. Anyone have one of those?

Thanks in advance.
 
I've never owned a scope bigger than 40mm. IMHO, the 50mm scopes are more of a marketing idea than anything else... If you are using a quality scope with good glass, you really don't need a huge lense. IMHO, if a person can't see an animal using a quality scope with a 40mm lense, its to dark to shoot.

I have used fixed power scopes a lot (Leupold 4x with a 32mm lense), hunting in heavy timber which is not ideal for light gathering, and have never felt handicaped hunting during legal hunting hours.
 
I've had two scopes with 50mm objectives and they are just too big. It raised the scope so high that my cheek weld on the stock suffered badly. The biggest lenses I've been able to shoot comfortably are 44mm, but I haven't had a scope with a lense bigger than 40mm in years. My favorites are 32-38mm, but I like lower powered scopes like 1.5x6x, 2x-7x, or fixed 4x and 6x scopes for most of my deer or bigger game hunting guns.

I think that 40mm is the best compromise between size and light gathering ability in a quality scope.

The quality of the glass and the coatings is the MOST important part of the light gathering/transmitting equation.
 
The only time I would consider a 50 mm or other large objective bell scope is if I was hunting almost entirely from a fixed stand (think south Texas senderos or elevated beanfield applications). Such hunting is done primarily at dawn and dusk, when the larger light gathering objective lens comes into it's own, plus you have time to mount the rifle carefully, thus mitigating it's less desireable handling qualities. I would consider it on a specialty long-range rifle, in a caliber such as a 7 mm magnum with 168 gr. VLD bullets. For your all-around 30-06, Kirk, stick with the 40 mm.
 
Yeah I probably don't need the bigger lens, but I always find myself wanting to get something that is a little better. Does anyone have a 50mm that they actually like?
 
Get a scope with good quality glass and coatings. 40MM is as big as you'll need. ;) 338375 and cramsey 3006 are spot on!
 
I have found my Leupold VXIII 2.5X8 has all the light gathering I need for dusk or dawn. In any legal shooting time it is all you need.
I would not own a 50MM scope. Of course my rigs are hunting rifles, and the larger objective lens scopes require a higher mounting than I want for fast shooting. I want to be looking through the scope when my cheek hits the comb of the stock.

So what if a 50mm is better in the moon light? Shooting then is illegal where I have hunted.

Regards,
Jerry
 
I checked out some scopes on rifles today ... a little surprised that I had a hard time noticing any real difference as far as how high the 50mm sat vs. the 40mm and 46mm scopes that I looked at. My cheek seemed to be in about the same position on all of them. I'm guessing that I would probably notice a difference once I started putting rounds through the rifle.

I think I'm giving up on the 50mm, but may be interested in some of the slightly larger scopes out there, like 42mm and 46mm that I am seeing.

Thanks for the info.

My next post will be about finding a good sling, so let me hear your opinions on that ;-)
 
Kirk, the difference is in the height of the rings. If you put a 50mm and a 40mm in the same rings, no difference. But, a 36-42mm scope can usually go in shorter rings and still clear the barrel and the bolt lift . . . that's what makes the difference.
 
Kirk_Ferentz said:
I checked out some scopes on rifles today ... a little surprised that I had a hard time noticing any real difference as far as how high the 50mm sat vs. the 40mm and 46mm scopes that I looked at. My cheek seemed to be in about the same position on all of them. I'm guessing that I would probably notice a difference once I started putting rounds through the rifle.

I think I'm giving up on the 50mm, but may be interested in some of the slightly larger scopes out there, like 42mm and 46mm that I am seeing.

Thanks for the info.

My next post will be about finding a good sling, so let me hear your opinions on that ;-)
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If you put as much time into hunting, as you do picking your gear, you will do well. Not to be rude, but you are really splitting hairs, and probably stressing yourself out for no valid reason...
I know for fact ,there are people that couldn't tell the difference , if you laid a 40mm and a 42 mm next to each other. You will never notice any practical difference.

I know you want to learn, and make the right choices, and thats a good thing. However, focus your time and energy on being able to shoot , and spend the rest of your time scouting.
 
Can't be doing any shooting right now anyway due to waiting for my rifle and everything else. Might as well work on spending my money on the right product in the meantime. I don't want to have to buy another scope.
 
Kirk_Ferentz said:
Thanks to all of you who chimed in on my other scope post. A lot of great reviews and info. I'm close to a decision, pending a few specific questions. The biggest one is whether I should opt for the bigger 50mm objective lens, which is going to bring in some much-needed light around dawn and dusk, or stick with the more conventional 40mm lens.

It sounds like the major reason that I might NOT to go with the 50mm lens is that it might raise the scope beyond the comfortable eye level. I'm thinking that it is also going to make the rifle/scope more combersome.

Anyone familiar with both types of scopes (or just the 50mm I suppose) and have any opinion on whether the extra height causes any problem?

One solution that I have been toying with is to get one of the "knotched" 50mm leupolds that wraps around the barrel and has a lower profile. Anyone have one of those?

Thanks in advance.
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Bigger objective doesn't always mean bigger light. The ratio of power to objective size has more to do with it, plus some elusive factor known as "twilight factor," which in simpest terms means that more power sometimes trumps the objective to power ratio (I have a book here that defines it, but can't find it right now). Also, the internal elements (optical elements) of the scopes are usually identical, so they don't transmit any more light. Only if you have a good quality 30mm scope with internals that are bigger do you really get a boost, and all things being equal, optical quality trumps everything (i.e., Ziess, etc.). I don't like anything bigger than 40mm because it requires high mounts, which causes problems with cheek weld unless you have a stock built to compensate for that. The higher center of gravity makes the rifle handle poorly if you need to get on something quickly, and the greater deviation from the boreline means that most ballistic charts will not be on or even very close for you (most are done with essentially low mounts). In other words, your 168 grain Federal .308 load sighted 2" high at 100 yards will not be on (or very close) at 200 yards; you might be on at some much greater distance with too much rise at mid-range to be optimal. None of this matters if you hunt only from stands, verify your rifle's actual trajectory on the range at every distance, etc., but I like to still hunt quite a bit. For all these reasons, I don't like big objectives, nor do like super high power in my scopes (nothing over 9x). You probably knew all this, but if not, I hope this helps you.
 
No I didn't know all of that. Thanks.

I'm pretty close to pulling the trigger on a leupold 3-10 X 40mm VX-3 (I think I'm getting all the specs right there). The equivalent nikon and zeiss were close, but the nikon is quite a bit heavier as is the zeiss (less so), and if I remember, the zeiss is more expensive.

The scope that I'd really like is the leupold 3-10 X 50mm VX-3L. Yes, I know that everyone is saying don't go 50mm, but these are the models that wrap around the barrel. When all is said and done, they mount as low or lower than a 40mm does (they mount like a 36mm). I wish they had a smaller objective lens like a 46mm, but 50mm is the smallest. Anyway, the reason I'm going with the conventional 40mm is the cost. The 3L is up $750 and over.

And no, not doing more ruminating ... just need to sit down and find the right vendor and make the purchase.
 
Go with the 40 and you wont be disappointed. I only have 50mm on my sniper/bench rifles. A basic Leupold mark 4 will even be able to handle a 50 bmg if you ever decide you need to go that big.
 
Kirk_Ferentz said:
No I didn't know all of that. Thanks.

I'm pretty close to pulling the trigger on a leupold 3-10 X 40mm VX-3 (I think I'm getting all the specs right there). The equivalent nikon and zeiss were close, but the nikon is quite a bit heavier as is the zeiss (less so), and if I remember, the zeiss is more expensive.

The scope that I'd really like is the leupold 3-10 X 50mm VX-3L. Yes, I know that everyone is saying don't go 50mm, but these are the models that wrap around the barrel. When all is said and done, they mount as low or lower than a 40mm does (they mount like a 36mm). I wish they had a smaller objective lens like a 46mm, but 50mm is the smallest. Anyway, the reason I'm going with the conventional 40mm is the cost. The 3L is up $750 and over.

And no, not doing more ruminating ... just need to sit down and find the right vendor and make the purchase.
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The Leupold VX-3 is a great scope. You can save quite a bit of coin buying used. There are no worries with used Leupold scopes, because they have a lifetime warranty, even though you are not the original owner
 
The theoretical difference in eye height between a 40 mm and 50mm is 5mm or about 1/5 of an inch (if the bells are equidistant from the barrel). I use a 3-12X56 scope and love it.
 
338375 said:
The Leupold VX-3 is a great scope. You can save quite a bit of coin buying used. There are no worries with used Leupold scopes, because they have a lifetime warranty, even though you are not the original owner
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Is there a good marketplace for used scopes?
 
I ended up ordering a Zeiss conquest 3-9X40mm. Should be arriving with the rings and base next week. I was thinking that I'd have to have someone professionally mount it, as someone told me that you should really have the rings lapped, but I have since heard that that is unecessary. So, I should be able to mount it myself and be off to the range in two weekends since I was able to pick up some ammo at a reasonable price (a rarity in my locale).

I wanted to get a cheaper Nikon, but it didn't sound like their 42mm would mount well on the leupold low rings. whatever, sounds like I can't go wrong with the zeiss.

I'll try to report back with a review.
 
That should be a great scope. A lot of people don't lap rings. I think a lot of people don't know about it, or how to do it.

After you get the base and bottom of the ring mounted, set the scope in the ring saddles. If it sets in easy, and you can tell the sides are parallel to the scope tube, and the bottom of the scope tube sits flush with the saddle, you don't need to worry about it. It will be fine.
Put th etop of the rings on, but don't tighten them completely until you get your scope set wher eyou want it for eye relief. The tighten down. Don't forget to make sure the scope is level too.
 
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