Lyman vs lee vs Alliant...

[Rule3]

It has probably been mentioned in the posts above but realize that ALLIANTS data only lists a MAX so in using that you should start at 10% below that .

Also all the different manuals and other sources if you change one thing in the "equation" everything changes.

Change the bullet, the primer the COL etc. Heck even different lot numbers of the same powder or different day of the week , humidity , what test equipment etc.

Even if you have the bullet makers manual your results will vary Do you have the same primer same brass etc, It will make slight differences.

If you do not have the bullet manual then you can either call them (Sierra are great folks) or use you best data available. LEE data is just data from somewhere else and it's as old as the book, they never tested anything, Not saying it's all bad)

When you use the powder companies data if it is not the same bullet then the COL will vary, so be careful on that and used the MIN charge to start.

 

[Boogsawaste]

That all makes sense. Appreciate the info!

 

[gwpercle]

Yes , it is confusing. I have a dozen manuals and that's how they are written....different labs, different testing proceedures, different results.
What I do is start with a load in the middle. Not a starting minimum or a maximum. Shoot it and see if I want to go hotter or back off some.
Very, very seldom do I find maximum loads necessary and usually find the accuracy load I'm looking for in the middle of the range.
I have added up the max. load + min load and divided that # by two to get average. Do this for loads listed in 3 or 4 manuals and use that average to get a mid-range starting point load. You have to start somewhere and the middle is usually safe ground. Don't start at maximum because that's not a good place to start!
Gary

 

[Jellybean]

Rule3 is right, there are many different things that will affect your results and his list is just the tip of the proverbial iceberg. As time goes by you will learn that some things will have a greater affect than others, such as primers. That is why it's so important to start low, because the closer you get to the top the more critical even those little differences can become. Pressure grows faster as the charge is increased so by starting low you are giving yourself an extra wide margin for error.

There was a time when data sources didn't give you near the information they do now, and there was a good reason for it, it doesn't really mean squat. The data they give is just a guide to go off of and nothing you do, or use, will be exactly the same as theirs. The information they don't give you is even more important, and as variable, and means just as little in the end. (The reason they included it is because their users asked for it by the way.)

 

[alwslate]

Nothing wrong with being careful if you're a beginner at handloading
but you need to understand the difference between a "maximum load"
and the top listed load. Seek out data or manuals that list the pressure
of published loads and you will see that top charges often are well
below standard pressure limits. +P loads often are barely above
standard pressure and well below +P limits. Phobia about handloading
"grenades" leads to stuck bullets and ruined bores sometimes.