March 2-25? 42mm vs 52

[Wolf76]

I'm a in the 42mm camp. The smaller objective is often better for cheek position on the stock.
Scabbards often fit poorly on big objectives (if horses factor into your hunts).
I've also read that the human eye can't really use the additional light generated by an objective larger than 42-44mm. This might explain why we see so many scopes in this objective size.
There certainly is a benefit to a larger objective-- whether or not that benefit applies to hunting is up to you.
A couple ounces of difference between the 2 isn't huge, but you wouldn't add a couple ounces to your pack just for the hell of it.
My bet is that you'll end up with the 42.

 

[30BR]

If memory serves, the March 50X had a 52mm objective. You're comparing that to an NF 12-42X56, which has a lower magnification and a larger objective.

FWIW, The difference in low light conditions is PROFOUND. My Weaver 46x48 T series, with a significantly smaller objective is PROFOUNDLY brighter, with a very minor difference in magnification. And by low light, I am not talking dusk or dawn; I am talking 1st relay at 600 yards at 9:00am with an overcast. NONE of my other scopes were ever as dark. (Sightron 36x, Leupold40X, Bushnell 30x, B&L 36X, NF Comp (fixed OR variable version), 12-42x, etc.). The only one as dark was the 80X March variable cranked up to max magnification, and it was fairly dark in even decent light at that setting.

 

[Wedgy]

I've also read that the human eye can't really use the additional light generated by an objective .

Human eye can open to ~7mm(less as we age) The light exiting the scope is a factor of the objective size divided by the power setting so 42mm divided by 6 power is 7mm which would be the max your eye could use. Any power above that is less than 7mm. At 20 power the exit pupil would be 42 divided by 20 = 2.1mm
The max light you could use from the 52mm objective would be 52mm divided by 7mm is at 7.2 power
At 20x the 52mm scope has a 2.6mm exit pupil.

 

[FTRshooter]

FWIW, The difference in low light conditions is PROFOUND. My Weaver 46x48 T series, with a significantly smaller objective is PROFOUNDLY brighter, with a very minor difference in magnification. And by low light, I am not talking dusk or dawn; I am talking 1st relay at 600 yards at 9:00am with an overcast. NONE of my other scopes were ever as dark. (Sightron 36x, Leupold40X, Bushnell 30x, B&L 36X, NF Comp (fixed OR variable version), 12-42x, etc.). The only one as dark was the 80X March variable cranked up to max magnification, and it was fairly dark in even decent light at that setting.

I don't know what you mean by "profound", I've never seen that used as a unit of measure in the performance of a riflescope.

At any rate, you are talking about a discontinued product, with which I have no experience. I started using March scopes in 2014 and was surprised at how much brighter my March-X 5-50X56 was compared to my Nightforce NXS 12-42X56. Both were set at 40X and on dark mornings for early relays I could now see the target well with my March, whereas the NF was darkish. I would estimate the difference to be about the equivalent of 1 f-stop, or thereabout.

Since it's all done with my mark 1 eyeball, it's all subjective.

 

[bigngreen]

I'd be a toss up, I've mounted quite a few and done load work for guys with both and I really didn't feel there was much of a difference unless your mounting requirements required higher or you cheek weld needed lower. The 52mm will out perform an AtacR in low light conditions by a LOT but I didn't have a AtacR in when I had any of the 42's. I personally lean to the 52 just cause!

 

[Wedgy]

I posted this picture before of some NF's, VX-6 50mm, S3 50mm and a March 42mm. Yes some have shades on, but the compactness of the 42 is pretty obvious.

 

[30BR]

I don't know what you mean by "profound", I've never seen that used as a unit of measure in the performance of a riflescope...
Since it's all done with my mark 1 eyeball, it's all subjective.

Yep; I have no way to quantify the difference, but I was taken aback by just how dark it was. Just wanted to caution folks who may be ready to plunk down $1,500 to $3,000 for a scope never to ASSUME price alone guarantees all the performance you're looking for. Trust but verify.

 

[OrionsStar]

I posted this picture before of some NF's, VX-6 50mm, S3 50mm and a March 42mm. Yes some have shades on, but the compactness of the 42 is pretty obvious.View attachment 176846View attachment 176847

Pardon my interruption. What ring set is on the rifle? Thanks much! Jim

 

[Greyfox]

I looked at both and went with the 52. Larger eye box and a bit better in low light/:shadows.

 

[Wedgy]

Pardon my interruption. What ring set is on the rifle? Thanks much! Jim

Burris Xtreme Tactical

Xtreme Tactical™ Rings | Burris Optics

www.burrisoptics.com

the Weavers are a bit lighter

 

[86alaskan]

I use a 42 on my 300wm carbon build. It really is very light and compact. Pass on the illumination, it's not all that great unless it's pretty dark. As for eyebox, I haven't got any issues with mine, but I feel like competition has tuned my rifle mounting to the point of exceptional consistency. When you mount the scope correctly, and practice getting on the rifle correctly, a slightly tight eyebox shouldn't be too big of an issue. The reticle is the FML1, and is well designed to be perfectly useable at 2.5x, as well as 25x. You lose a bit of subtensio detail at the lower powers, but the thicker stadia draw the natural aiming point to center and allow for fairly precise 2.5x shooting.