I have soldered many of them on shotgun barrels. They key is keeping the solder where it needs to be, only polish the area immediately under the base and I tin with a iron. Have to be careful with rosin flux that it does not drip and remove the existing blue. If things go right you can usually get by with a touch up blue. I usually charge around 200$ for a job like that. I can do it if you are not in a huge hurry, back logged at the moment.

http://www.bertramandco.com/
Booking African hunts, firearms import services

Here for the meltdowns