I watched this Brit pellet gun video
12 foot pound pellet gun ranging is a lot like long range hunting with a 7mmRM, but divide all the ranges by 10.
he shows a lens cover called an accucover.
I Googled that and found
Products - Accucover
I ordered one from England and it arrived today, 8 days later.
It really works.
I hunt deer at 400 -500 yards with a Leupold 2x7x32 [no parallax adjustment] with a Stoney Point turret for elevation, a Leica CRF 1600, a kestrel
, a chart I make from Quickload/Quicktarget, a rear bag, and a swivel bipod.
The way I have been overcoming parallax is to back my eye way back from the eyepiece until the image is smaller than the eyepiece. Then I center the image in the eyepiece by moving my head. This works for target shooting, but is not fast.
The accucover allows me to have my head way forward, in the middle, or way back, and the target is centered fast.
I have made two pics while looking at the floor. My first pic has the camera sort of in line, and the second is out of line with the scope tube. You can see the fast correction from the second pic to the first would be to get the cross hairs to line up with the marks on the scope cover.