discrepancy in load data

[mzimmers]

Can someone tell me why the 40 grain Hornady loads with H4895 here in the forum differ so much from Hodgdon's data?

Forum: 24.5 - 26.7
Hodgdon: 26.0 - 27.7C

I'm trying to extrapolate between 40 and 50 grain load data for my 45s, but this makes me a bit cautious.

Thanks.

[Fred_C_Dobbs]

The header information on this web site's load data page says it was copied from Hodgdon. Seems to me that would mean that either the Hodgdon data changed of the guy who put that note at the top of the page lied.

[Bitman]

I'm by no means an expert, but I bet if you look at 4 different loading manuals.
You'll find 4 different starting and max loads listed for a specific load.
Just depends on what case, primer, and barrel is used.

[Fred_C_Dobbs]

mzimmers, are you looking in the Hodgdon manual or the Hornady manual?

[mzimmers]

Hodgdon. I don't have a Hornady manual.

[Sidewinderwa]

Barnes has min 26.0 max 28.0

Berger min 23.5 max 26.5

I did a pressure ladder test on MY rifle and had no pressure signs at over 28 grains. Depends on the rifle and components. My rifle likes a load under all the max loads so that is what I load. I am more interested in accuracy than speed.

[Fred_C_Dobbs]

Okay, that's what I thought. If there's a difference between what they've recorded on this web site, and if they faithfully reproduced the data that was in the Hodgdon manual then, that would lead me to believe the data in the Hodgdon manual you have is from a different series of tests which had slightly different results. When the powder manufacturers publish new edition manuals, they don't just add data for new cartridges, they also update data for some of the old ones.

The elephant in the room -- the obvious truth that no one in the industry dares mention -- is that no one yet has invented the perfect pressure testing method. They're all flawed in one way or the other. Even if they were perfect, there's a long list of variables that will affect individual test results, including that the "power" contained in any given powder tends to vary over time, even from one lot to the next.

Anyway, that's why conventional wisdom says to start 10% below the published max charge and work toward max in small increments. They expect you to start at the low end, look for signs of excessive pressure as the loads get hotter, and decide for yourself where the upper limit is for that firearm.

[Rick in Oregon]

Fred: In reference to the above, the following comes to mind: "Common sense is required"............. Never truer than when reloading.

We all must be ever-vigilent, as when 50,000+ psi goes off 4" from my face, I like to know I'll still be smiling later.