Re: 30 cal Hornady SST
Your mileage may vary. Seated magazine length in a SS M 70 300 RUM, the 165 SSTs shot poor. What I found that worked in this particular rifle was Sierra 164 HP Game Kings. It's ogive design got the bullet closer to the lands - less jump. Which is what this rifle needed.
Robert A. Rinker states in his book "Understanding Firearm Ballistics" in Chapter 16, Bullet Design & Performance, page 213 Notes On Bullets:
"Bullets with grooves crimped around their body have lower accuracy because the bullet is deformed in an area that disrupts the flow of air and disturbs the aerodynamic stability. Even if the groove is perfectly even and uniform around its full length, which it rarely will be, it will still lower accuracy. It will also reduce the life of the case from over-working the metal. This can cause splits at the mouth that are unnecessary. Factory ammo... ."
From my experience, I will not disagree with Rinker.