I'm looking to mount this on a Henry single shot, H015 with a Talley mount. What is the 'eye box' measurement of this scope? — 1 Answer

"Eyebox" is not a measured specification from riflescope manufacturers. Eyebox can be considered the area outside of optical center that you can move your pupil and still have complete or partial view through the scope. This area has to do mainly with exit pupil, that is the objective lens diameter divided by whatever magnification your scope is set at. Eye relief is another consideration of eyebox, and is the distance from the ocular lens to your eye. Both of these measurements result in a certain area that can be considered the eyebox, but again, manufacturers to not specify this area. Also, the field of view, which is the distance across your view from right to left, is not only predicated on the design of the ocular lens and "eyebox" which is also known as the whole ocular assembly of lenses, but on the objective lens design as well. If you are looking for the distance away from the ocular lens on this scope, it is listed as from 3 inches to 3.4, which is less than many scopes. Eye relief is always shorter at higher power. If you're looking for the exit pupil, which is the all-important circle of light exiting from the ocular lens of the scope, it is from 4.5mm to 9.8mm, both of which are huge. The normal human eye has a pupil for younger people that rarely gets over 7mm in completely dark conditions, and older people significantly less. That means that this scope will provide way more light than can be used by a pupil in hunting conditions, which are never completely without light. Mounted on your Henry you should be fine with eye relief but will probably have to mount the scope as far back as possible, and maybe even use extension rings to bring it closer to your eye, depending on your facial structure and physical build. For instance, short necks are less forgiving than longer ones.