I am not a legal expert and it's not a legal advice, but in case of a bolt-action rifle, I think the action is still legally treated as a firearm. So you can buy most parts without hassle (barrel, trigger, stock), but you need to go through the FFL to buy the action.
Reference: https://www.brownells.com/aspx/general/faqdetail.aspx?fid=10...
Anyone is allowed to manufacture a gun, as long as they don't sell it. If you want to sell it, you'd need a license.
1. CNC the Remington 700 action: https://www.practicalmachinist.com/vb/gunsmithing/making-rem... . This is the hard part and would probably need a week of dedicated work...
2. Buy barrel, trigger and stock.
3. Everything mostly just fits into the action, so assembly is just like putting lego pieces together.
The jig is the most expensive part, costing about $160 or so, but once you have it there's no wear parts and you can use the jig to build as many as you want.