The point of the commercial, from the standpoint of the company that coughed up the big bucks for it, was that oils were different, and you had to think about your choices.

Whether that was true or not for motor lubricant back then was debatable, but today's handloader must not think, "Bullets are bullets." Technology and progress have taken that option from us.

I started reloading in the late 1960s when bullet manufacturing was not much different among the bullet makers. Whether from big factories hammering out payloads for commercial ammo or from the smaller firms like Speer, Sierra, and Hornady who served the hobby reloaders, there was not much difference among component bullets. Everyone used very similar jacket materials and thicknesses, and if you lined up several brands of .30-caliber, 180-grain bullets, they looked very much alike. The only common bullet that strayed from the "same-as" syndrome was the Nosler Partition; its solid jacket partition made it longer than bullets of the same weight but of conventional construction.

Reloading data even reflected this situation. Propellant companies seldom identified the bullet they used for developing loads and, for the large part, didn't need to. Yes, changing from one bullet brand to another could change pressure, but the effects were generally small enough to remain within the safe zone. That's assuming the handloader observed the most important safety rule of load development: Always begin at the published starting load and work up toward the maximum in reasonable increments, testing each increment before shooting the next higher one.

Today, we have a broad choice of bullets to meet any shooting need. With this proliferation, the ways bullets are made have dramatically changed, creating significant differences among them that affect how much powder you load.

Let's consider some bullet characteristics that can influence load safety. For the sake of discussion, I'm talking about bullets of the same diameter and weight but of different construction.

Bullet Length
The big hitters in bullet length are diameter and weight. A .30-caliber, 150-grain bullet is longer than a .35-caliber bullet of the same weight. Weight itself is a function of the material densities. Lead is denser--weighs more per volume unit--than copper, steel, or plastic. Pure lead is heavier than lead alloys.

Thirty years ago, the copper jackets on most big-game bullets made up 15 to 20 percent of the total weight, with the remainder being dense lead. Today the jacket is heavier, making up more than 50 percent of the total weight in premium bullets. In projectiles like the original Barnes X-Bullet, the lead is totally eliminated.

Increasing the amount of lighter jacket material relative to lead makes the bullet longer if diameter and weight remain constant. A longer bullet intrudes deeper into the case, often necessitating a charge reduction, and increases the next characteristic.