About twice the size groups as using the matchkings has been my experience with them in SSG 69...About 5/8--3/4 inch..168 .matchkings can be dicey sometimes on deer--sometimes they will expand then sometimes they act like fmj's..Gamekings on the other hand are pretty reliable, acting similiar to ballistic tips in performance..
I shot a box or two of them thru my 18 1/2" barreled Sako .30-06 (so velocities should be similar to 22" .308) with great performance on deer but not quite as accurate for me as Nosler Ballistic Tips. The latter are awfully tender inside 100 yards, tho. I think I used 4350 but I'd have to check my records. Matchking are strictly target bullets and are not designed to expand (or NOT to expand, for that matter) but merely to be monotonously accurate.
I have had good results with both Varget and RE-15 with the 165+ grain bullets in my .308. My rifle likes 43.8-44.2 grains if I remember right using that round. It should be around 2650-2700ish loaded to 2.800 OAL.
I will be using these bullets for hunting white tail deer. I picked the gamekings because they were the closes ones to the 168gr matchkings. I am new to reloading i'm learning from my friend on how to load them I know that there are alot of other brands out there so any help would be greatly appreciated. Oh and i'm shooting them out of a Rem. 5R w/24in mil. spec barrel
I have tried many many loads in my Remington PSS, and the two best for 165-168 gr bullets have been 42 gr of either RL-15 or IMR 4064. Use these and play with your seating depth, and I know you'll find something you'll like.
If you are trying to stick close to the 168 SMK, you might try the 168 Nosler Combined Technology Ballistic Tip. I get very similar results to the 168 SMK when I load these. I did exactly what you are trying to do and this was the route I took.
That being said, when you find some time to experiment drop down to the 155 lapua scenars for target shooting and the 155 hornady a-max ballistic tip for hunting. These have out performed the 168's in every way for me. I'll be glad to share my load data on them if you end up picking some up.