You're looking for a rifle with minimum wear.
First, remove the bolt from the receiver and examine the bolt face; is it smooth and new looking or pitted and rough? If pitted, the gun has seen hard use.
The barrel is iffy. Most guys don't know how to clean copper and fouling from the barrel. With bolt still removed, point the barrel at a light-source and look down the bore. If it is shiny, it's at least clean. If dirty or dusty, that is a bargaining point. You are buying a used gun. Tell the pawnbroker you're concerned about the barrel if you make an offer.
Look at the stock for gouges or splits. Look at the screws, if they are beat-up it is an indicator.
Does the rifle come with a scope? With scope mount? Rings? Have bought a number of used rifles w/quality scopes at a good price. Leupold scopes, most often.
Never offer to pay the asking price. Always offer at least 25% below the asking price or much less if the guy has it marked way up. To get your best deal at a pawnshop, be sure to tell the guy you're gonna pay with CASH. Cash is king at the pawnshop. Not so much at a gunshop, but they should discount you 5% at least for not using a credit card...
Best deals at pawnshops. You can recognize junkers. Don't buy a junker. Rem 700, Win 70, Sako, Tikka, maybe a Savage or Ruger. I would avoid Ruger or Browning, Stevens, Mossberg.
If pawnbroker won't deal, leave right then. The next one will. Might not get as great a deal on an in-demand rifle as would have 3mos ago, but pawnbroker should save you money and bargain with you for cash...
When you get your new rifle, clean the barrel well with copper remover like Barnes CR-10. May as well buy a Dewey coated rod, some correct size phosphor brushes, solvent & patches to clean with if don't already own them...