Soft Silver Solder melts at about 400 F it's about 95Sn-5Ag and it's often used to solder stainless steel as it stays shiney.It's not a high strength solder.
Hard Silver Solder is a high strength BRAZE ["solder " is used but is a poor term and often leads to confusion !] Melting points of about 1100 F or higher.
Braze or welding requires knowledge of the heat effect of the weld on the bolt .Front of the bolt must be kept cool and post braze/weld should be tempered.
And Watson , bring your revolver !