Start Charge/Max Charge Variance by Book/Site

[CrystalRedTintcoat]

In the spirit of checking, double-checking, and rechecking powder loads before reloading, I decided to also check multiple information sources:

• Lyman 50th Edition reloading manual
• One Book/One Caliper book
• Hodgdon's web site

On paper, this would seem like a logical, rational, and safe thing to do. However, I'm seeing a different set of numbers by Book/Site:

Screen Shot 2020-10-02 at 6.54.10 PM.jpg

For the powders in my possesion it seems like the Winchester AutoComp is pretty simple (6.0 start --> 6.8 max) since the numbers match between sources. But for the Hodgon 700-X there's quite a variance between the sources.

Two questions for the forum:

1. Why is there such a disparity between sources?
2. For the 700-X should I bias toward Lyman (3.6 grain to start) or toward Hodgdan's recommendation (4.5 to start)?

[Sandspider500]

Well, one is for a fmj and the other is a lead rn

[CrystalRedTintcoat]

I checked FMJ across all sources.


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[CrystalRedTintcoat]

[CrystalRedTintcoat]

Just double checked powder 700-X:

Hodge on Site
4.4 - 4.9 (FMJ)

Lyman
3.6 - 4.8 (FMJ)

One book/one caliber
4.4 - 4.9 (FMJ HDY)

So, still I have one outlier. Lyman.


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[CrystalRedTintcoat]

This is not handgun specific but the comments seem to apply. Posting here in hopes this thread helps the next guy ...

https://www.trapshooters.com/threads/lyman-reloading-data-vs-hodgdon-data.857527/

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[Sandspider500]

Umm, 3 different bullets, 3 different lots of powder, 3 different test barrels.

[CrystalRedTintcoat]

Same bullet (45 ACP 230 grain FMJ). Two powders (autocomp, 700-x)


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[CrystalRedTintcoat]

http://bulletin.accurateshooter.com/2018/01/why-does-load-data-vary-between-reloading-manuals/

[Sandspider500]

No, Lyman 230gr Speer tmj, hodgdon 230gr Hornady fmj flat point and the other I don't know. I'm only referring to the 700x loads as I haven't looked at the autocomp yet. They could have slightly different seating depths, not by much but we're talking about a difference of 1300 cup here, so basically nothing. There could be a 1300 cup difference from shot to shot with the same bullet and powder.

[CrystalRedTintcoat]

Sandspider: turns out I made TWO errors in my original research. I thought I was looking up FMJ but, as you you uncovered, I misread LRN. Also I misread TMJ. Now that I've properly looked up the powder load by caliper, weight AND bullet type I'm in better. Shape.

Still, however, the Lynman book is off as noted above. I had written to them today but hadn't hear back yet.

[Bumslie]

You're way overthinking this.

Lyman uses the same data that goes back to the 46th edition for that combination with 700x

Stop worrying so much and load up. They aren't wrong.

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[slamfire1]

Load data is just a guide. The slope of the pressure curve is exponential, little differences in test article and components make huge changes to the pressure curve. Look at the data and take a best guess.

And then, if you are really worried, shoot over a chronograph and see if the velocity of your ammunition is within published values. I guarantee, if your reloads are moving faster than book, your pressures are higher than book.

I know, based on my history, that the 1910 45ACP round used in the development for the 1911 pushed a 230 FMJ at 800 fps. The actual load was 5.0 grs Bullseye. When I conduct load development in my 1911's, with a 230 grain anything, 800 fps is my velocity target for a "full power" load. Most average in the 790's. I have created loads that functioned the pistol that were just above 700 fps. With the fast burning powders I use, pressures were safe, but I risk function issues with low power loads in semi auto pistols. I have created loads that pushed the bullet over 900 fps, but I did not like the recoil, and it was hard on the gun. I could tell by how long my shock buffs lasted. Fifty round of the 900 fps stuff would disintegrate a shock buff. Ergo, the gun was being pounded.

But over time, I have developed my own velocity criteria, by examining known standards such as factory ammunition, and data from books. I shoot the stuff in all weather conditions, and as long as function is good, and velocities are not insane, the load is good. I will say, over time, I have tended to cut my loads more than I have tended to increase my loads. High pressure loads are not tolerant of changes.

[divingin]

If you look at old load manuals vs newer ones from the same source, you'll generally see a progression of reduction of max charges. Mostly due to the more litigious nature of the public (and an increase in idiocy of that public, but that's neither her nor there.) I think it's from people looking at the manuals as a bible, rather than a reference - "normal" now is to think that anything in the book is safe, whereas "normal" used to be to work up the load to your firearm and loading equipment using the data as a rough guideline.

Short version: loads (especially max loads) are listed as the amount of liability risk the publisher is willing to take on.

[pennstater]

Load data is just a guide. The slope of the pressure curve is exponential, little differences in test article and components make huge changes to the pressure curve. Look at the data and take a best guess.

And then, if you are really worried, shoot over a chronograph and see if the velocity of your ammunition is within published values. I guarantee, if your reloads are moving faster than book, your pressures are higher than book.

I know, based on my history, that the 1910 45ACP round used in the development for the 1911 pushed a 230 FMJ at 800 fps. The actual load was 5.0 grs Bullseye. When I conduct load development in my 1911's, with a 230 grain anything, 800 fps is my velocity target for a "full power" load. Most average in the 790's. I have created loads that functioned the pistol that were just above 700 fps. With the fast burning powders I use, pressures were safe, but I risk function issues with low power loads in semi auto pistols. I have created loads that pushed the bullet over 900 fps, but I did not like the recoil, and it was hard on the gun. I could tell by how long my shock buffs lasted. Fifty round of the 900 fps stuff would disintegrate a shock buff. Ergo, the gun was being pounded.

But over time, I have developed my own velocity criteria, by examining known standards such as factory ammunition, and data from books. I shoot the stuff in all weather conditions, and as long as function is good, and velocities are not insane, the load is good. I will say, over time, I have tended to cut my loads more than I have tended to increase my loads. High pressure loads are not tolerant of changes.

This is a very good post. And exactly what I have learned over the years of loading for my Springfield 1911-A1 mil-spec. Pretty much settled on 5.2gr Universal/230gr LRN or plated for 785-800 fps MV over the screens. It's a good load.