i understand that it helps to give a better cheek-weld w/the stock.  is it really necessary though?  im getting a Mcmillan A3 stock and i want opinions.  im prolly gonna end up mounting a scope w/a 44mm objective so its not really to high.  plus the A3 stock has a straight high comb to begin with.  if i do decide to go w/the adj.  do i want internal or external?  i read somewhere that some shooters sometimes duct-tape sleeping pad foam to the stock to build it up for a higher stock etc...

anyhelp would be appreciated

thanks

Are you planing on bench/match shooting or is this for a plinker?  If it's a plinker, then I think the cheek piece is a luxury.  Also unless you're mounting the optic above the carry handle, I'd say it'll probably put your line of view too high.

If you expect to shoot tiny groups, you need a repeatable cheek weld (bone of your cheek firmly planted on the stock). A jaw or chin weld won't cut it for tiny groups. If it takes an A3 stock to get the proper weld, then it is money well spent.