Difference in scope numbers?

[Bob-WY]

I am somewhat ignorant to what the numbers mean to a hunter in the field:

VX-3HD CDS-ZL 3.5-10x 50mm
VX-3HD CDS-ZL 3.5-10x 40mm

What real difference will it make? Looking to put it on a pronghorn rifle, out to maybe 300 yards given my current ability.

They are about $100 apart, the 50MM has a bigger end so would mounting it be an issue?

What other real difference would it make?

 

[TN2shot07]

Mounting the 50 isn’t an issue but it does require the scope to be mounted in taller rings. That’s just a personal preference as I want it to be as low as possible for a better cheek weld. Also a little added weight for the 50 but probably not a big deal for an antelope rifle!

 

[cahunter805]

Depending on your current base/rings a 50mm might mount right up. A 50mm may be a touch brighter due to the bigger objective but for a 300 yard hunting rifle a 40mm is fine IMO.
What reticle are you looking at?

 

[noharleyyet]

40 all day...tad better cheek weld mitigation, ample light especially with the new coatings..and they simply look better on a rifle.

 

[ludville1]

I would go 50...all of my hunting rifles have at least a 50mm objective. All else being equal, the larger objective has the ability to transmit more light. IMO, looks much better on the rifle also.

 

[mtmuley]

No need for Hubble glass on a hunting rifle. Looks funny too. mtmuley

 

[nrpate05]

I'd go 40mm. It gets the scope a little closer to the barrel, which, all else being equal is a good thing. Also, if it is an antelope rifle, you probably don't need the greatest light gathering ability which I would see as the only real benefit to the bigger objective.

 

[rwc101]

My first scope was a 50. Won't go that big again.

 

[noharleyyet]

My first scope was a 50. Won't go that big again.

As was mine...on a Ruger #1 no less. What was I thinking..

 

[ludville1]

To me, a 40mm scope on a hunting rifle looks like a "kids toy". I deer hunt in thick cover...swamps and such in Northern Michigan...every minute of light counts!

 

[mtmuley]

To me, a 40mm scope on a hunting rifle looks like a "kids toy". I deer hunt in thick cover...swamps and such in Northern Michigan...every minute of light counts!

1/2 hour before and 1/2 hour after sunset here in Montana. Even at extended ranges haven't needed more than 40mm. That's what I have on my kid's toy .300 RUM. mtmuley

 

[Bob-WY]

This will go on a new rifle, specifically for pronghorn, so last light in the woods, isn't an issue (that's my other elk/deer rifle!). Most of my unsuccessful pronghorn hunts I am back at the truck by dark.

Sounds like I'll go with the 40!

Leupold site says duplex reticle

THANKS!

 

[Deleted member 20812]

The size of the objective lens makes a difference in the exit pupil. Whether the difference in exit pupil is a factor depends.

At 10x, a 40mm objective has an exit pupil of 4.0. A 50mm has an exit pupil of 5.0. At 8x, the exit pupil is 5.0 and 6.25. Based on your age and the health of your eyes, your pupil may not be able to dilate to 6.2. If your pupil cannot dilate to the same size as the exit pupil of your optic then the benefit is wasted.

I guess it largely depends on how far you intend to shoot at low light and what magnification you would choose. At 6x it’s pretty much irrelevant.

I’ve never used more than 40 for mounting reasons, cheek weld reasons, weight, and cost. I could care less how it looks.

YMMV.

 

[ludville1]

1/2 hour before and 1/2 hour after sunset here in Montana. Even at extended ranges haven't needed more than 40mm. That's what I have on my kid's toy .300 RUM. mtmuley

...but don't you know, this is America, where everything is "the bigger, the better"? Lol!

 

[Deleted member 20812]

...but don't you know, this is America, where everything is "the bigger, the better"? Lol!

Or a waste of money.

 

[ludville1]

Or a waste of money.

Oh I hear ya...just like our hunting, and all of our hunting equipment is a "waste of money", seeing that none of us "need" to do it...right?

 

[belshawelk]

Well, I guess I am on the other side. I have lots of 40 and 50's. To me the 50 is well worth it. I have two of the same guns, one with a 40 and one with a 50. There is noticeable light transmission difference in the 50 in low light conditions. In daylight they are the same.

Any new important gun for me will be topped with a 50

 

[ludville1]

Totally agree.

 

[VikingsGuy]

The size of the objective lens makes a difference in the exit pupil. Whether the difference in exit pupil is a factor depends.

At 10x, a 40mm objective has an exit pupil of 4.0. A 50mm has an exit pupil of 5.0. At 8x, the exit pupil is 5.0 and 6.25. Based on your age and the health of your eyes, your pupil may not be able to dilate to 6.2. If your pupil cannot dilate to the same size as the exit pupil of your optic then the benefit is wasted.

I guess it largely depends on how far you intend to shoot at low light and what magnification you would choose. At 6x it’s pretty much irrelevant.

I’ve never used more than 40 for mounting reasons, cheek weld reasons, weight, and cost. I could care less how it looks.

YMMV.

BINGO!!

Light transmission is primarily about glass quality and coatings. If your pupil can dilate enough to take advantage of the extra exit pupil size at the zoom levels you hunt at then you will also perceive more brightness. If not, no impact on brightness - there is no universal brightness advantage to object size. Typically older guys can't see the difference and younger guys can. Sadly I am on the wrong side of this question.

 

[cahunter805]

I normally just buy whatever scope I want to use for the rifle and if it only comes in 50mm it’s fine. I’ve found a lot of people just assume they need taller rings than they actually do. I just mounted a 56mm in medium rings and it cleared fine.