I glass-bedded the action & floated the barrel on my muzzleloader - I did the job myself for about $25 and 3 hours of work. This was a cheap-o muzzleloader, so I'm not suggesting that anyone screw up an expensive rifle if they don't know what they are doing. But I had never done it before - just read a lot, got some pictures from some other guys who had done it, read the glass-bedding instructions, and went ahead and did it.

In my case, the muzzy's best groups were about 2.5" at 100 yards (3 shot groups) - after the job, the best group has been 1.25" - a pretty noticeable improvement.