Most of the time you can get a 700 action around 600-700. Or buy a used rifle and buy it for the action and save more. Trueing the action typically 200-250 maybe more but not where I live. Typical cost on firing pin springs depending on your smith is really just the cost of the parts and a minimal up charge as it is not a time consuming process by any means. Rails are dependent on who and what you buy, 40-200 bucks… and ruffly 100-200 for nitride or cerakote, depending on how much your doing, might be more. So most of the time you're probably going to be around about a 1200 to the smith maybe more for trueing, bedding, trigger job, barrel cut and chamber, threading ext. Depending on what products you chose to buy, and use in your build all compound into the price of the finished product. Example 1600 for a custom action, , 40-400 for a trigger, 350- 1200 for a stock, rifle barrel 350-800, rings and bases 100-500+, optics 100-6000, muzzle break 50-300, bottom metal aftermarket 40-300 then you throw on the machining, trueing, and general labor and it's not hard to be into a semi custom rifle 2500 bucks. And unfortunately that's why most "custom" rifles run a person 5000 +. Also factor in shooting components, now that adds on as well. So truly what it really comes down to is more of the cost of the parts, and 1200- more to the smith for their time and skills.