The most common reloading question, one that keeps reoccurring, is a version of this: “I have just purchased a .500 boom buster and intend to load 400-grain projectiles using ZXY powder, can you please suggest an accurate load? My usual target is small dragons!”
I cannot make up my mind if our dragon-slaying hero is attempting to avoid the process of load development entirely and hopes that some other reloader will do the work for him or if, in fact, he is simply unaware.
Fact number one in relation to any rifle is simply that every barrel, like humans, is an individual. Like humans, it still has its likes and dislikes. What one accepts, another will reject.
Many powder companies and individuals spend a lot of time and effort producing reloading manuals that suggest powder loads using various sized projectiles in the various cartridge of calibres. The projectile used may or may not be nominated; sometimes merely a weight will be suggested.
It is very important that such manuals be used, with loads that start below the maximum. Otherwise, your personal safety is at risk.
Yes, I agree that the manuals are only guides but they are the best information available to the home reloader. Someone has ascertained pressure figures that need to be respected.
It’s not true that manuals specify lower initial charge weights because of legal liability. Nor can you then reason that the maximum loads are safe to use as a starting load.
You must start at a lower-than-maximum powder charge because you have no idea of exactly how the barrel is cut nor how the metallurgy of the barrel will react to a certain projectile and the pressures that will be created upon firing.
In addition, different projectiles, even of the same weight, are likely to have different bearing surfaces, possibly not visible to the naked eye. Again, pressure will be affected and may rise to dangerous levels.
You must be certain of the powder you use to create your new cartridge: a common mistake is to use fast pistol powder in a rifle cartridge, and the result is always a blown-up action that may injure the shooter!
The final piece of damning evidence comes from benchrest competition in the USA. Some years ago, a well-known gunsmith was asked by a top rifleman to make him two identical benchrest rifles and develop loads for them.
The gunsmith carried out the rifleman’s request, including load-developing rifle #1. Using logic, he came to the conclusion that as the load was safe in one rifle it should be safe in the other, as they were identical. Using the same load in rifle #2, he blew the primers. He re-measured rifle #2 and found that it was mechanically identical to rifle #1.
Both barrels were from the same maker. The only difference was the individual barrel metallurgy. This shows how careful you must be.