You're not talking about hunting rifles are you ?
The most likely gun to score well would be an old fullbore target rifle with aperture sights like the Omark 44 mentioned above or a Parker Hale.
There could also be a few almost unsaleable wildcats around with a huge amount spent on the build, yet virtually zero resale value now, that offer fair accuracy potential if you can handle the reloading set up.
If you allow handloading then the amount spent on that will be more than the rifle.
The requirement for an off the scale pricing really make this complicated and easy to criticise.
I suggest you change the rules to $1000 and must use factory ammo but can use as much as you like setting up practising and in repeated attempts to get a score. Also tighten up that the targets have to be shot same day and first shot only, a bit like Norway's challenge. Perhaps require all on one piece of paper like Gimp's challenge.
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