Go Back > Forums > Small Caliber Discussion Board

Thread Tools Display Modes
Old 06-14-2018, 01:08 AM
carbon carbon is offline
Junior Member
Join Date: Jun 2018
Posts: 22
Default A different take on large scope objectives (like 56mm)

New member here! Hi!

I just bought a CZ 527 in .204 Ruger, and need a scope for shooting prairie dogs. I also have a -10.5 diopter eyes, which is very bad nearsightedness. I can count on one hand the number of people I’ve personally met with worse eyes. For example, without my Coke bottle glasses on, I cannot see the typical eye chart *at all* or recognize family members at a few paces. I can see sharply at ~3 inches.

But, with glasses, I see 20/20. I mention all this because from what I gather, I lose roughly 7%-10% of light coming into my eye (can’t find my source for this stat anymore). When I used to use contacts, the brightness difference was noticeable. I use glasses because I see better with them vs contacts. BTW I buy the best high-index plastic lenses for my glasses to keep weight down.

Soooo, what am I getting at? Two things; a question and a public service announcement. The question will be about “eyebox” (as I understand it, a black magic combination of exit pupil + eye relief) and the PSA will be regarding crap eyesight.

Eyebox: I see a lot of pooh-poohing of large objective scopes. I have a 4-14x44 scope, and at 14x, where I’d be when shooting p-dogs at longer ranges, I have to get my head juuust right to not have any occluding “black crescents”. At that magnification, the exit pupil is 3.14. So my question is, will a 56mm front objective scope, set at 14x (e.p.=4), make head placement noticeably less strict? Remember, I’m not asking about the amount of light; this is more about ease-of-use and comfort. And I’m not sure how much my thick eyeglasses make the eyebox situation worse.

In short, large objective scopes would seem to be easier to quickly look through, and less tiring during an all day p-dog shoot. Is a 56mm scope noticeably more user friendly than a 44mm? Weight is not a concern, as I shoot from a bench.

And the PSA: not all people have nice eyes, so don’t come down too hard on large objective scopes. I imagine some buy them for status, but some may be helped by them.
Reply With Quote
Old 06-14-2018, 02:27 AM
hemiallen hemiallen is offline
Supporting Member
Join Date: Oct 2009
Posts: 1,232

I imagine you will need a comb adjustment via additional material, soft pads, etc to get a CZ527 stock to fit most folks with such a high scope mounting that the large objective will require.

But some folks don't have tight face placement, or tall faces making this not easy to use a blanket statement of what you may need.
Reply With Quote
Old 06-14-2018, 05:14 AM
SEM SEM is offline
Senior Member
Join Date: Jan 2018
Location: Sac CA
Posts: 303

I suppose with your vision as it is you have adjusted the eye piece to your needs, I have noticed on some of my scopes that I need to readjust them at the higher settings to clear up the image, Just a thought I know you asked about objective diameter.
Reply With Quote
Old 06-14-2018, 09:52 AM
56S 56S is offline
Senior Member
Join Date: Dec 2017
Location: East Central Ohio
Posts: 115

In my limited experience the ease of finding that sweet spot has more to do with the actual brand and model of the scope and the magnification level than the size of the objective lens. What the larger objective scopes will do is allow more light to enter and provide a clearer picture. For example my 50mm scopes can be set to 9X where my 44mm will be at 12X to get a good clear view of the target. Magnification without enough light is sometimes worthless. Reducing the power usually increases the ease of finding that sweet spot. On the 527 a 50mm with front AO ring just fits with standard CZ rings. A 56mm side focus might fit.
Reply With Quote
Old 06-14-2018, 11:33 AM
JSH JSH is offline
Senior Member
Join Date: Aug 2016
Location: Kansas US of A
Posts: 617

I have caught a lot of flack for buying higher end glass. I ignore those folks input with nothing more than a casual glance.

To my understanding, in a nutshell, the light transmission has more to do with coatings than the size of the tube. I forget the measurement, but there is only a certain amount of light the eye will use. The size of the tube is more in line with elevation and windage.

I am also near sighted, I thought I was bad till I read your description. I will not spend any more money on glass unless I can look through it first.

Don't buy glass and judge it on a crystal clear blue bird day, they all look good then. Much like buying a used car in the rain, dents don't show.
Go to a cloudy overcast day, then the light gathering capabilities of optics are noticed.
I once had the opportunity to look through some high end glass, a comma and several zeros or nines in the price. First day or so was fairly bright and clear. My glass looked as good or better than his. A front came through really over cast. I struggled to see things, looked through the "other" and I was shocked.

Everyone's eyes are different and we all see things a bit different. Only you can make the call of what works for you.
Reply With Quote
Old 06-14-2018, 01:20 PM
pertnear pertnear is offline
Senior Member
Join Date: Jan 2015
Posts: 220

I know nothing about these having never needed one but here is Leupold's solution to large objective lenses mounted low enough on a rifle to comfortably look through.

Reply With Quote
Old 06-14-2018, 01:41 PM
hemiallen hemiallen is offline
Supporting Member
Join Date: Oct 2009
Posts: 1,232

I guess my thouht was wrong on needing high ring mounting for the 56mm scope.
Reply With Quote
Old 06-14-2018, 01:49 PM
Bayou City Boy Bayou City Boy is offline
Supporting Member
Join Date: Sep 2006
Location: Tomball/Klein, Texas
Posts: 3,989

Scope quality is far more dependent on the quality of the glass used as opposed to how big the glass is.


I miss mean Tweets, competence, and $1.79 per gallon gasoline.

Yo no creo en santos que orinan.

Women and cats will do as they please. Men and dogs should relax and just get used to the idea.

Going keyboard postal over something that you read on the internet is like seeing a pile of dog crap on the sidewalk and choosing to step in it rather than stepping around it.

If You're Afraid To Offend, You Can't Be Honest - Thomas Paine
Reply With Quote
Old 06-14-2018, 02:56 PM
410gauge 410gauge is offline
Senior Member
Join Date: Jun 2013
Posts: 245

I'm with BCB on this one. Quality of glass supersedes objective lens. Unfortunately you get what you pay for. I shoot with a number of guys who insist on 50mm or larger objective lens. That's fine if the glass is top notch, but beyond 300 yds. the quality of glass takes over in my opinion. I have several Swaro Z5 3.5-18x44 with the BRX reticle. The optics on these scopes are pretty amazing (at least for my eyes). One can make 400+ yd. GS shots quite regularly with this scope and this particular reticle. Other brands are not near as bright or clear as these Swaro's...particularly at distance. Lotsa of scope brands that will stay with Swarovski and Nightforce at shorter ranges, but if you are going out to the longer ranges the higher grade glass is worth the extra money in my opinion. Binocular's are the same. Try looking all day through binocular's with-out really good glass, and see how your eyes feel at the end of the day! Just my .02 worth. 410gauge
Reply With Quote
Old 06-14-2018, 03:17 PM
NeilA. NeilA. is offline
Senior Member
Join Date: Dec 2012
Location: Western Washington
Posts: 301

I took 410gauge’ s recommendation on trying the Swarovski Z-5 3.5x18x44 with the BRX reticle. It is now my favorite scope, a pleasure to use. They are available for around $1300.

They also offer a slightly heavier reticle, may work better for your eyesight.
Reply With Quote

exit pupil, eyebox, large, objective, scope

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT. The time now is 02:37 AM.

Powered by vBulletin® Version 3.8.1
Copyright ©2000 - 2023, Jelsoft Enterprises Ltd.