Working up test loads; how many and measuring powder

[FunYet]

I recently bought a Dillon 650 and am ready to start loading. I'm going to start with .38 special, then will move on to .357 magnum. I also plan to eventually load .44 special and .44 magnum.

I know I'm supposed to start with the lightest recommended load of powder and am not to exceed the maximum (I'm using the Lyman loading guide). My question is, when working up a variety of test loads at what increments of measurement should I load (from minimum to maximum) and roughly how many rounds of each loading is enough to test? I don't have a chronograph so my tests will be based strictly on the results of my shooting.

 

[Zak Smith]

A chronograph is invaluable when it comes to load development.

The charge increment size depends on how much powder we're talking about. For rifles using 40-50gr powder, I might use 1gr. For 9x19 loads using 4-5gr, I might use 0.2gr increments.

 

[griz]

Please use common sense no matter how much, or how good the advice on the internet sounds.

When working up a load with a new (to me) powder in a handgun round, I will usually load only 2 at the bottom charge and increase the number of rounds so that I have at least 5 for the "middle" charge and above. My minimum may also be lower than the one in the book if they have a small spread between high and low. Often I will not even load the max rounds for the first trip. This is because I'll take them all to the range and work up, and since I will stop where I feel comfortable this minimizes taking rounds apart.

With rifle rounds I am even more cautious because the pressure is higher to begin with. It doesn't bother me to take a series of say, 10% below max, 7% below, 5% below, 4% below, and 3% below max charges to the range and shoot only those. I'll stop if there are problems, but assuming those are fine, the next trip will have 2%, 1%, and max loads. I do use a chrono and what it tells you is invaluable. But I loaded for many years without one, it certainly can be done.

Here is a short tale to explain my caution. I once made up some loads for a fairly new (to me) 22-250 with a powder and bullet I had never used in that rifle. I thought I knew enough to put up the first loads just under max, about a hald a grain under the book max if I remeber right. The first shot blew gas in my face and expanded the case so much that the primer fell out after the bolt was forced open. Turns out the barrel was pretty fast, the bullet was much softer than it should have been for that caliber, and I learned my lesson. ALWAYS START LOW.