outdoorz4me,
Calling rifles are a subject that is near and dear to my heart.
While big game hunting is by far my major focus, it seems that I spend the most days in the field every years shooting called cats and coyotes.
I didn't notice where you are from or really how you hunt, I hunt predators day and night using an electronic caller, but I'll still toss out my theory for the perfect predator calling stable. Take it or Leave it, this is what I believe.
Day Time Calling Guns
I hunt daytime dogs on the ground using a remote digital caller. I usually setup about 15-20 yards directly cross wind from the caller. My daytime calling rifles are almost always light weight hunting rifles that are chambered in a varmint caliber. Guns like a Remington Model Seven in 17 Rem or 223, Remington LS in 221 Fireball, Remington VL SF in 17 Rem or 221 or 223, and etc. Light quick handling guns that are generally shot at 15-50 yards but can reach out and zap em when the hang at 200 yards. The scope of choice for me is either Burris 1.5-6x or Leupold 1.5-6x42mm with the scope always cranked down to 1.5x power.
When I am doing a two person stand, especially with a novice shooter or when visibility is poor (either from flatness of terrain, brush or fog), I'll put the front shooter on a 10ga shotgun. My predator shotgun in an old Ithaca Mag-10, the predecessor of the Remington SP-10, with a 24" barrel. The back shooter, who is about 30 yards crosswind from the call, is still on the lightweight varmint rifle. About the only exception to this is when I get a very good vantage point, I'll take out my medium weight varmint rifle, like a Winchester Coyote and rifles of that ilk, that has a 4.5-14x scope on it in something like 223 Ackley Improved. Our average shot is probably around 50 yards,
Night Calling Guns
When we hunt at night, we are generally calling from a vehicle and the shooters are shooting out of the top of a camper shell. The camper shell has a padded railing that is used for a front rest. The first shooter is using a benchrest style of gun, w/ a 4.5-14x heavy duplex reticle, in something like 243 or 6mm BR. The rear of the rifle is generally supported using a rear bag. These rifles are capable of shooting minute of gnat. The second shooter, who also runs the caller & the lights, has the Ithaca Mag-10 for "truck dogs". Shots at night will vary from 15 feet to 350 yards. Our average shot at night is in the 125 yard range.