Okay, anyone want to give me some instructions on how to do this without screwing up a barrel? I have an old Rem 721 with a soldered on front sight, and it needs to be removed so I can chuck up the barrel in a lathe to recrown it. The former owner was one of those old school clean from the muzzle end kind of guys, and the crown is in pretty bad shape. Also, how far back do you think a guy would generally have to go to get rid of most of the bad from improper cleaning methods? It's not washed out horrible or anything, but it could use some help.

I'm thinking on removing the sight, you need to keep the heat on the sight and not the barrel, but am at a loss after that. Fast, slow, what?

Sorry, I can't speak for the Remington, but the sightd I've taken off of ols Husqvarnas didn't require an awful lot of heat. Soft solder of some kind. You may want to consider some of Brownell's Heat Stop if you are that concerned.

Clamp the barrel upside-down horizontally, sight-down, in the bench vise. Clamp a pair of vise-grips to the sight ramp and heat ONLY the sight ramp rapidly. The sight, with vise-grips attached, will fall off as soon as the solder is heated but before the barrel becomes too hot, because the solder joint insulates the barrel steel from the ramp's residual heat.

I've recrowned several dozen old rifles and never had to counterbore deeper than perhaps 3/8" and that was an exception, most cleaned up nicely with 1/8" to 1/4" recess. My most dramatically successful example was a Savage 1895 (yes, an original 1895 made by J.M.Marlin!) that keyholed every bullet fired but when counterbored 1/4" the groups with factory 303 Savage ammo tightened up to 1.5 MOA with iron sights. For the counterbore I used a 30-cal chamber reamer that had been ground with no throat, so the reamer neck's forward origin served as the actual cutting part of the counterbore.
Regards, Joe

Thanks Joe, that's what I was thinking. Heat on the ramp only, heat fast so it doesn't have time to transfer. Makes sense to me.

This rifle is trying to shoot, I think it just needs some help in the way of a cutback and recrown. Once again, I appreciate it.

Good idea about the vise grips, I used a wooden dowel to apply pressure instead.

Also, I like to have the sight pointing to the side instead of straight down and also have a piece of fine steel wool handy to swipe the area with as soon as the sight falls off.

With the sight to the side, you can give it a wipe and better see what you are doing than when when the sight is pointing downward. Just make sure you don't let the steel wool touch the torch ever!

I took the ft sight off a u s krag to replace a sawed of base- they are hard soldered (silver) had to get it red to get it off I filled the bore with heat control paste worked fine And by the way they have a very shallow dovetail so you have to push them out to the side