Hi Ron,

You can buy rifle blinders at most rifle supply shops (Champion's
Choice, Neal Johnson's, etc.) or you can make one yourself from a
translucent material like a plastic milk jug. Some people prefer a
black, opaque blinder, but most use a translucent one. The idea is to
block what your non-sighting eye is seeing so you don't have to squint
and close it to have a clear sight picture with your sighting eye.
Supposedly, by not contorting your face muscles to squint, you are more
relaxed and can get a better sight picture.
Personally, I think this theory holds more true for 3 position
shooters as they are at a resting heart rate and not at elevated heart
rates like a biathlete is. Just like your ammo question, you have to
do some tests and see what works best for you. If you can use a
blinder and get good, tight groups, better. Some close their non-
sighting eye, even with some facial contortion, and shoot tighter
groups. What ever works and gets you five for five! Note that you see
most of the top biathletes using blinders..... that should tell you
something, eh?

Jay Bender