Rifle Scopes Disappointed with US Optics ST-10 exit pupil

[fnbrowning]

I recently bought a new USO ST-10 TPAL, and used it on the range for the first time yesterday. The optics clarity is great, and eye relief fine. But I'm having a real problem with the - (I believe it's called) - exit pupil. The diameter of the circle of the image is very critical, and any little head movement at all and some of the image is lost.
I remember that not long ago USO went from a 44mm objective to the current 37mm.

Schmidt & Bender, IOR Valdada, SWFA to mention a few offer the 10x in 42mm, and Leupold does not go below 40mm.
Not withstanding the better light gathering ability of a larger objective, the corresponding larger exit pupil allows a coarser eye to optics alignment.

I would have thought that having a larger exit pupil in a sniper scope would be better because it will allow the shooter to acquire a sight picture in a hurry on that under less than optimum conditions.
As it is now with my USO ST-10 TPAL, it takes an extra moment to get my eye in the sweet spot where there is full vision, and it is annoying.

 

[Captain Kirk]

The exit pupil and the eyebox will be fairly tight on that optic, one of the downfalls of the smaller objective. Check to ensure the scope and eye relief are setup properly. To do this, get behind your rifle with your eyes closed and get a good cheek weld, open your eyes and see if you have a clear sight picture. If your position needs to be adjusted to get a good sight picture, your optic is not setup on the rifle properly, scope height, cheek weld and scope position forward or rearward needs to be adjusted.

Also check your diopter adjustment. Best way to adjust it is to look at the sky or a white wall as a solid backstop only paying attention to the clarity of the reticle. Make small adjustments, get behind the scope with your eyes closed for a few seconds, open them and see if the reticle is clear or out of focus. Don't make adjustments while looking through the optic, your eye will adjust for the out of focus and just blur the target. What you are effectively doing is ensuring the reticle AND the image are clear, if the diopter adjustment is not setup properly to your eye, either the reticle or the target will look in or out of focus.

Kirk R

 

[Papa Zero Three]

The exit pupil and the eyebox will be fairly tight on that optic, one of the downfalls of the smaller objective. Check to ensure the scope and eye relief are setup properly. To do this, get behind your rifle with your eyes closed and get a good cheek weld, open your eyes and see if you have a clear sight picture. If your position needs to be adjusted to get a good sight picture, your optic is not setup on the rifle properly, scope height, cheek weld and scope position forward or rearward needs to be adjusted.

Also check your diopter adjustment. Best way to adjust it is to look at the sky or a white wall as a solid backstop only paying attention to the clarity of the reticle. Make small adjustments, get behind the scope with your eyes closed for a few seconds, open them and see if the reticle is clear or out of focus. Don't make adjustments while looking through the optic, your eye will adjust for the out of focus and just blur the target. What you are effectively doing is ensuring the reticle AND the image are clear, if the diopter adjustment is not setup properly to your eye, either the reticle or the target will look in or out of focus.

Kirk R

+1 to this suggestion

 

[sniperdude]

I just had a similar problem on a rifle/scope, was the eye relief needed to be adjusted , just had to move the scope foreward a bit and all worked fine after

 

[fnbrowning]

see next post

 

[fnbrowning]

Captain Kirk's information was spot-on. Thanks to his helpful advice enabled me to maintain a more comfortable cheek weld, and make the best use of my new USO scope.
Today, I got the best groups I've shot in years.
Between some posts here on the EREK system and this thread, Snipers Hide has been very useful to me.
I like it here!

 

[Captain Kirk]

Glad we could all help