If your gun will shoot em (and most Encores/Omegas will) I say stick with 150 loads for anything over 150yds. The 250SST is THE bullet to use and be sure you have the black MMP sabots (they should come with the bullets if you buy the Hornady box instead of the TC Shockwave package). The key too 150grn charges and longranges is in the sabot. And of course they will be TOUGHER to load and seat properly but you must have that much pressure for a proper seal or otherwise you won't get a true clean burn (that's why so many guys have trouble making 150s shoot).

Also I recommend trashcaning ALL pellets. I know they are convenient but you simply wont get the consistency or cleaner burn of a granular load. I despised changing from pellets but was shown the truth by a Knight factory rep lastyear in Wyoming at a mfgrs event in Cody. (LOL well I sorta paid attention, I now shoot granular powder but it's Vhitavouri N110 in my Savage!)

With a properly shooting 150grn 250SST load you should be able to sight dead on at 100 which should leave you about 4" low at 200 and believe it or not, 16" low at 300 with enough killing power for deersized animals. I would hold the line on elk at about 225 or 250 unless you go up too the 300SST (which is what I shoot in my Savage). Run a simple brush through the bore after each shot and clean it after each half dozen and you will realize 300yd potential. Stick with 100grn loads and 200yds is your TOPS, they reallly start falling after 150yds with only 100grns.

Good luck and let us know how you do,
RA