The first thing you need to understand about load data is that all of it is individual to a specific firearm and loading technique, none of it is written in stone. A load listed by anybody as their maximum is unlikely to translate to your firearm and technique as your maximum. You may not have any pressure signs even several grains above their max, or you may start seeing pressure signs well short of their max.
Bullets come in a few designs that affect pressures, the primary one being the bullet's weight. But pressure is also affected by the bullet's friction and material, and indirectly by its length. Load data is usable for all bullets of similar weight and design, ie, data for a flat-base pointed soft-point can be used for all bullets of similar weight and bearing surface area. Switching to a ballistic-tip, or a boat-tail, or a cast bullet, or monolithic copper or brass bullet may have differences significant enough to alter pressures.
Powder equivalents do not mean you can swap them, it merely means they are useful within similar ranges of cartridge capacities, velocities and bullet weights - they are NOT interchangeable.
If you are starting out, use lowish loads, and work up to pressure signs, although there is no real need to push the limits.
Jaeger wrote:Hi,
I just started reloading and find it confusing when it comes to load data from different manufacturers.
I use a Mauser M18 in 223 (22 inch barrel, 1:10 twist) and started reloading using ADI AR2206H powder.
I picked up Hornady 52gr BTHP match bullets and the ADI reloading manual doesn’t have this bullet. So I though I use the Hornady app and just use a equivalent powder type. But that’s where all the confusion starts. The ADI website states that AR2206H is similar to IMR4895 or AA2460. Both of these powders are listed on the Hornady website, but have vastly different starting and max loads. So they don’t appear to be that similar at all.
I then compared what is listed in the ADI manual vs other information for these powders. For example, ADI has a starting load of 21.0 and max of 22.6 for Barnes TSXFB 55gr. The Barnes data has 23.8 - 25.8 for IMR4895 and 21.6 - 23.6 for AA2460.
That are huge differences and now I’m really confused how to figure out a safe load for bullets not listed in the ADI manual.
Can someone enlighten me please??
Cheers,
Andi