[Unclenick]

Sierra's certainly not the only game in town. Guys who've done ultrasonic void testing say they find Berger more consistent, but then you pay even more. At the other end of the cost spectrum, I have a Remington 600 in .222 that prefers 50 grain Hornady spire points at 100 yards over Sierra 52 and 53 grain MatchKings. The slightly shorter Hornady is more stable.

The Noslers I've used have either worked well or not. If I set one in caliper jaws sideways (base to tip aligned with jaws) and with the pressure ring at the heel outside the jaws and hold it up to the light, I see a small crack of light along the cylindrical bearing surface portion that grows toward the tip. In other words, they've had a very slight taper instead of a being true cylinder in that portion of the bullet, perhaps to make it easier for the punch in a forming die to push them out. Sierra and Berger and Hornady bullets I've measured have all had pretty parallel sides. It seems that some guns just love that slight Nosler taper and some can't make it shoot particularly well.

My suspicion is that in some throats it tends to help center the bullet better, but in others it allows the bullet to favor one side of the bore. But that's just a suspicion. I don't have a measurement to show that's actually the issue or if guns that don't like it are just exhibiting a variation of the more mundane random factors that always make some guns like one bullet over another. Anyway, the bottom line is always the same: you try different stuff to see what works best in your gun.