OEM parts can usually be found for any reasonably modern rifle. For aftermarket parts the Ruger 10/22 will be hard to beat. You can build an entire rifle and not use a single Ruger part. New and used OEM parts are easy to find because so many people customize the 10/22.
Check out numerix,and brownells, web sites.if they have a lot of parts then they are abundant. My guess for your business model, would be Marlins, thereís a sticky on this website, that tells you what the sears, monkey wards , and house brand really are. Those are going to be the cheapest 22s at the gun shows ,pawn shops and,garage sales . The gun shows in Indiana that Iíve been to, donít really have many deals, these guys are trying to make a living too.
Good luck on your new endeavor.
ps, if this turns into a business, thereís gonna be a lot of paperwork, atf , irs , etc.
Many of the old 22's had a one piece barrel and action. If the bore is not good I would stay away from those. Or learn to do barrel liners? Ebay is loaded with parts and stocks for many rifles. If it is not there now it will show up soon.
I think you could make money as long as you target your audience. If you want to target the 35 year old and younger market, than take beat up "Tactical" type .22's, and refinish those, that have good bore's, and just need a little TLC.
If you want to restore the classics, i.e. rifles like Win 52, Marlin 39, Browning SA-22, appeal to the old geezers (like myself 54 years old), and find rifles again that don't need much in parts, but some TLC. I'm amazed at how many rifles I see that just need a little elbow grease, some stock sanding/Lacquer, and some light removal of surface rust, and you have a Gem.
Just like guys who take older cars and add a little elbow grease, you could make a little walking around money.
Im glad you used the term 'refurb' rather than 'restore'. Far too often I see something posted as 'restored' and is certainly not, but does qualify as refurbed. For instance, a higher quality polish and bluing than original is not correct. It will be a lot less expensive to refurb though still nice to use the correct bits, and research/consider carefully whatever you do to something that may well be a true collectable! You see this often on Antiques Roadshow where an item is worth 1/3 'refinished' from what it would have been original.
If you actually want a shot at making some money - not just tinkering and doing fun stuff....
Pick one or two popular 22 models. Say a Marlin Model 60 and a Ruger 10/22.
Buy broken/non-functioning guns CHEAP. Clean them and and swap parts to get them running - but do no more than that other than buying the occasional inexpensive part (like common springs that always break)... Sell them at current market prices. Become intimately familiar with them and their market.
Part out the stuff that's left over - those guns are fairly common and somebody will want the oddball parts for their project. Only buy parts occasionally. So for example - you may need to buy some Model 60 ejector springs.. Ok - they are cheap.. but don't spend $80 for a replacement stock for a gun that will sell $125.00
Avoid the urge to refinish the wood and reblue or refinish the metal. That stuff costs a lot, takes a lot of time, and generally doesn't really increase the value.
Don't get into weird stuff like Daisy or Hamilton 22's. Don't get into oddball foreign stuff. You can't get parts for them and when you can they cost a fortune. They don't really sell anyway - so you could easily drop $200 in parts on a gun that will eventually sell for $150.