Loading manuals

[VA Shooter]

Why is it that loading manuals have different starting loads and different max loads. For example Hodgdon has 250g cast starting load 8.2g of IMR SR 4756 @ 786fps and 10,600psi and max load 9.0g @ 864fps and 12,200psi. Now Lyman 45th edition (old) says 250g cast starting load 9.0g of IMR SR 4756 @ 630fps and max @ 12.5g and 951fps Who's data do you go by.

 

[Jimbo357mag]

There are many variables; method of pressure testing, different barrels/guns/fixtures, different components (brass/primers/bullets), different lots of powder, different weather conditions, etc. etc.

The best thing to do is look at as much data as you can and translate that to your situation. Where there is a lot of data there will be generalities that are apparent. With data that is scarce for a particular cartridge select what is a safe starting place, say 10% below a max charge with components that match-up well, and compare the actual shooting with factory ammo to get a feel for what you are working with. A chronograph will give you data points to work with. After that work up a load with your gun being careful to not over-stress anything.

Simple, huh? Your brain and experience will guide you as well as asking friends for help. I think you could start with the newest data from the powder manufacturer as long as it is not way out of line, but that is just me. 8) 8)

...Jimbo

 

[Flash]

Just start with the lower charge and work up to see how it shoots in your gun. Ken Waters published some excelent manuals, showing loads which gave the best and worst accuracy, high pressure, difficult bolt lift, load density, etc. If you can find those, they are worth getting.

 

[Donaldjr1969]

Another thing worth noting is to see what the load manual uses for testing of each caliber. Some, like the Lyman #49 manual, almost exclusively use a universal receiver. For example, 44 Magnum data is from a universal receiver with a 4" barrel. So the loads may seem a little slow. But then, I have no idea if there is a way to vent a minute amount of pressure to replicate pressure loss from a revolver's barrel to cylinder gap. Now my Hornady #7, and I assume the current #8, manual lists specific firearms used. Many of their loads are fired through actual guns. Their 44 Magnum data is gathered from a 7½" barreled Redhawk. Since I have a 7½" Super Redhawk, their data most likely will come the closest to what I can expect from my gun.

 

[WESHOOT2]

What I do: I collect as much data as I can, I figure the range of the start loads, and I start somewhere near the middle of those.
Then I work upward. Slow-like.


...in MY gun...

...unless you test you guess...

 

[VA Shooter]

Thanks for your help I think I need to do some research and take your advice and slowly work up some loads

 

[BCB]

I collect all the data I can from whatever sources I have...

I average all the starting loads and then average all the maximum loads...

Then I take these two numbers and get the average of them...

That is the starting load for me...

Good-luck...BCB

 

[Jimbo357mag]

I collect all the data I can from whatever sources I have...

I average all the starting loads and then average all the maximum loads...

Then I take these two numbers and get the average of them...

That is the starting load for me...

Good-luck...BCB

I guess that would make you an 'average' reloader? :D :D :mrgreen:

...Just kidding...Jimbo