Yes I took it off. The standard connectors that are used are called chicago screws, here's a pic.

Once it's off the sling I just scuffed the surface with some fine sandpaper so the solder would stick. The cartridge head can be cut from the casing with either a hacksaw or a dremel cutoff wheel. If the primer comes loose just put it back in place and squeeze it in a vise, it'll press right back in. I then filed the back side of the case head to smooth out the saw marks. When I soldered it, I held the soldering iron to the back of the cartridge head until it was hot enough to cover the back with with solder. To connect the two parts I held the screw in a vise and placed the casing head on top of the screw. I then placed the soldering iron to the top of the rifle casing and held it there until everything got hot enough to melt the solder. You might have to wiggle everything around to get the two halves straight, I used a pair of needle nose pliers. When both halves are aligned properly, just remove the soldering iron, and let it cool. Now just buff with a dremel tool and you're done.