taper mounts are nice, and make it convenient to move a can from one rifle to the next with out have to pull the muzzle device but they don't really work any better than a direct thread on once its re-tightened after the first couple shots. plus you have the added cost dropping at least an extra hundred dollars on mounts for each rifle, while that's not bad, add up 150-200 per mount for 7 or 8 rifles and very quickly you will be spending more money on mounts than the can its self. add in the fact the silencer companies love to come out with new mounts each year so finding say a surefire 762ss mount in 1/2-28 from 3 years ago is like finding a pot of gold at times.
pretty much everything comes with either 1/2 or 5/8 x 28 threads and quality adapters can be found for less than 20 bucks online. theres really no reason to buy a mount for a rifle that allready has a mount on it unless you really like the look of the mount