Start with proven gun!
The better quality the guns from that maker the less likely you'll get a lemon. Also consider the source. An estate sale is probably not lemons. Take old Winchester 22 bolt guns. People don't appreciate them anymore. Great guns and seldom anything wrong other than being beat to hell or a minor problem that can be fixed. Don't expect a used gun to be perfect but these days the new guns seem to have as many or more problems because of a lack of quality control. I bought a marlin bolt 22 and it had a bad crown and crappy trigger. Once addressed the gun shot great. I bought a used Ruger 77 that looked great, had the bedding removed from the tip of the barrel attempting to free float but no other bedding was done. Doesn't shoot that well but bedding should take care of it. Sometimes you get used guns nobody makes anymore and sometimes you get ones guys have tinkered with and ruined. It's rare to get a true lemon on the used market but I'm sure they are out there.
The better quality the guns from that maker the less likely you'll get a lemon. Also consider the source. An estate sale is probably not lemons. Take old Winchester 22 bolt guns. People don't appreciate them anymore. Great guns and seldom anything wrong other than being beat to hell or a minor problem that can be fixed. Don't expect a used gun to be perfect but these days the new guns seem to have as many or more problems because of a lack of quality control. I bought a marlin bolt 22 and it had a bad crown and crappy trigger. Once addressed the gun shot great. I bought a used Ruger 77 that looked great, had the bedding removed from the tip of the barrel attempting to free float but no other bedding was done. Doesn't shoot that well but bedding should take care of it. Sometimes you get used guns nobody makes anymore and sometimes you get ones guys have tinkered with and ruined. It's rare to get a true lemon on the used market but I'm sure they are out there.