They are pretty proud of the 175 SMK.. the story on how the "168" became the standard for 1000yd shooting is interesting. In short one of the top shooters of the time shot a world record with the 168 SMK and everyone started using it. Even though it's not ideal for 1000yd shooting. Across the course with a m1a yes. The 175 offer a better BC but, the 175's have the same BC as the 88gr eld-m. If you are using the 224 Valkyrie or 22 nosler heck even the 223/5.56 it's all a wash. I'm shooting 90gr Sierra's from a modified mag in my AR getting close 2500 FPS with H4895.
The Sierra 168's were designed as a 300M bullet. They debuted and won at the Mexico City Olympics (They were called 168 Internationals back then). For Highpower hey were initially used in Mexican Match (where the 173 FMJ's were pulled and replaced over the same primered and charged case) I'm guessing because they were closest in weight to the 173's. 168's did well at 600 yards, but ran out of gas at 1k because of their short boat tail out of the M14'S. (Sharpsman will be along shortly to contradict me). The 175SMK's were designed at the request of the USMC who had been working on a product improvement project for ammo to shoot to 1K in the M40A1's. The 175's were essentially a match analog to the 173 FMJ's.
If you're looking for a load for an AR10, try Varget under a 175 or 185 Juggies. It's what the cool kids are using out of their M110's out to 1K.
