Here is the procedure I use for reattaching, or installing a replacement handle on a 700. Clean the surfaces, and make sure they fit properly. Sometimes when a 700 handle is pulled loose, the saddle gets bent a bit. The handle must be correctly positionned for the bolt to work properly. Install the bolt body in the receiver, almost closed, but unlocked. Place the handle in position, with the rotation stopping shoulder contacting the corresponding flat of the boltway. Make a little indexing mark on the rear of the bolt and handle; I use a vibrating engraver. I made a little jig to hold the handle in place on the bolt. This is important, the handle must be held in place securely while being brazed. I use a paste type high temperature silver solder, silver and flux combined. No harm in using heat stop paste and/or anti-scale compound. You can wrap the bolt body with wet rags, to reduce heat spreading up the body. With the braze applied, and the handle securely clamped in place, I heat the saddle and rear of the bolt with a fairly large O/A tip. I want to bring the heat up fast, and not spend time cooking the thing. Keep playing the flame, watch for the silver to melt. You will see the shiney line around all edges of the saddel. You can hold the bolt in your bare hand by the lug end. The heat will not get to the lugs. I let it cool below red, and then finish cooling with water. Wash off any flux, clean up any silver that has flowed out of the joint. A tap can be used to clean the threads. Polish, blast and park, whatever, according to the finish desired.