You didn't say which cases you have but in 223 it doesn't usually make much difference. The Winchester max load is 26.2 grains (w/ FMJ, 26.3gr w/SP) which isn't a bad load but may be on the mild side compared to military ammo but not by much and the cases may last longer. That is the max load by Winchester also, not a starting load. Some people really like 26.5 grains of W748 and somewhere around 27.0 grains of W748 will match the hottest military ammo. You can start with 25.0, 25.5 or 26.0 grains and see how it is. I like the Winchester load data myself. The Speer manual uses the CCI 450 primer with W748, which is similar to the Rem 7 1/2, but I don't always agree with the Speer load data.