For high velocity rounds a series of cones seems to be the best options going right now , the better comercial cans are useing some sort of cones , SRT uses stepped cones , AAC uses several varation of cones KAC is using a fluted cone.
Their are several ways that they can be made , rather than try to explain all of them tell us what kind of equiptment you have access to , Lathe , mill? , can you weld at all?
Its realy not brain surgery , a series of flat baffles will work well but the unit will have to be bigger to make up for the lack of effeciency of the flat baffle , their a suppressor called a Tac-16 that work well , its a 223 can but works well enough to make a 22-250 ear safe , its just some flat washers with small cones on the face to help "peel" some of the gas off
The AAC 762SD is a great suppressor , here is an X-ray of the pre 2008 unit as you can see their ain't alot to it. This suppressor worked very well and they have since just went to a slightly more effecient cone desgine
the new cone is said to look like this one and I think that new suppressor might have a couple more cones , this is also the same cone that the AAC Cyclone uses , its a great suppressor , very effective
here is an X-ray of an OPs Inc suppressor and an Surefire suppressor side by side , as seen their baffle system is pretty simple just aseries of bowl shapped cones and more of them , notice that they are ported to cause irregular gass flow
Here is a simple designe that a buddy used to make a suppressor for a 300 RUM , it worked very well , the can is apretty heavy and long but it is trying to suppress alot of gass , as you can see its simple a series of flat fender washers pressed into a cone shape and tac welded to a spacer then the whole stack was tacked together and pressed into an outer sleeve and the endcaps were welded solid to the outer tube