I forged the bolt handle on my mauser and after much filing and smoothing I still have some dents and marks that I want to remove. I dont want to remove any more metal in these areas and I was wondering what type of solder or filler I could use to fill in these areas and then smoothe out with a file and possibly blue later. I was hoping to use gas welding torch and solder. I may be able to tig weld it if necessary.

Any advice appreciated.

You’re gonna be pretty hard pressed to find solder that will match blued steel. Why not just weld them up and file to match?

You'll want to keep the heat localized so using the TIG would probably be best. You can use a good old metal clothes hanger for the filler. Be sure to sand off the finish first. Don't let the heat spread beyond the handle. Use a good heat sink and even some of Brownells Heat Control Paste to protect the cocking notch. Good luck.