Which manual to believe?

[oldmarine]

Being a rookie to reloading, there is a lot to figure out.
I'm going to switch to HS6 powder to reload .38 spl-110 gr XTP. The Lee manual suggests 7.0 gr for the starting load, producing 1071 FPS. Hornady's manual suggests 6.8 gr starting load, producing 850 FPS. I'm getting confused at the disparity of information between the two manuals.

Thanks in advance for any help I may get here.
R.

[Hellrazor]

Which is the newest manual you have?

Here is a link to Hodgdons reloading info.

http://www.hodgdonreloading.com/

They are showing a starting load of 7gr at 1071fps and a max load of 7.8gr at 1178fps. So I am assuming Lee is harvesting data from the manufacturer.

[oldmarine]

Hellrazor,
Thanks for the links. I have the 2nd edition of the Lee book, and the Hornady book is their 9th edition. I just bought the Hodgdon 2015 manual, but honestly, didn't even think to check their data.
Thanks again,
R

[versifier]

Lee doesn't do any ballistics or pressure testing, they just borrow data from other sources, mostly from Hornady and Hodgdon, but others too.

Every lab is different. Each test could use any production gun or a universal receiver. Every batch of brass, powder, primers, and bullets are different for each test. And there are different techs running the tests. You never know exactly when any given published test was performed, it might be twenty or thirty years old and components change over time. What would really be surprising is if they all were in agreement!

This is exactly the reason why I recommend THREE CURRENT MANUALS. Even assuming there were no mistakes in data transcription/data entry, it is unlikely that three different sources would make the same mistake independently. So, if two sources differ, check a third and even a fourth and go with either those that agree or an average of all of them. One manual is potentially dangerous, two are often confusing, three is better and four or more is best.

FWIW, those .2gr at the START level are unlikely to cause any problems. A chrono might show some velocity differences, might not. A pressure gage might show some difference, might not. The degree of crimp could hide a small difference like that. When one really must be cautious is when you see difference in the MAX numbers. At least with a revolver you are not forced to work within a semi-auto's working functional envelope. Sometimes with rifle loads there are differences of several grains between various START loads and also and of more concern between different MAX loads. Then also some rifles have their personal MAX levels below the published ones, with their fired cases showing serious pressure signs at charge levels significantly lower than expected.

BUT, noticing the unexplained difference, it was an extremely smart move to stop and ask. You are turning out to be one very safe loader. Get yourself copies of the Sierra and Lyman manuals ASAP. Even if you try the exact same listed recipe, the numbers will not be the same as in any manual except by blind luck against astronomical odds. And you know what? It will still put holes in the paper, and no matter how complete any manual might be, it can never predict what loads your guns will like best. You have to work up each load, for each gun, one at a time. The most important skill any loader must have to be safe and successful is.... patience. And of course the good sense to stop and ask when something doesn't make sense, but that is a form of patience too.

[Hellrazor]

I always check the powder manufacturers website for reloading data when questions come up. That should be the most up to date information.

[Kirbydoc]

oldmarine, as Versifier said when you stop and ask questions you will keep yourself safe. If you are in doubt don't continue until you know for sure. You want confusion? My Lyman manual says 6.5 to 9.0 grains!
Hodgdon's web page says 7.0 to 7.8 grains. So starting load at 6.5 gr. won't stick a pill (bullet) in the barrel.

From Nosler's website: pa·tience [pey-shuhns] noun
1. the quality of being patient, as the bearing of provocation, annoyance, misfortune, or pain, without complaint, loss of temper, irritation, or the like.
2. an ability or willingness to suppress restlessness or annoyance when confronted with delay: to have patience with a slow learner.
http://www.nosler.com/

[noylj]

Loading 1.5gn won't stick a bullet in a barrel. Having NO powder in the case will stick a bullet.
All reloading manuals are correct: for the gun they used and the exact lot numbers of components they used—including the bullet. If these variables didn't exist, there would be only one manual, as all the rest would just be a repeat
You don't have their exact components and you sure don't have their guns, so your results will be slightly different.
You check at least two sources and start with the lowest starting load, just as Kirbydoc says above.

[oldmarine]

Great and very valuable advice. Thank you. Being recently retired, I have all the time and patience necessary. I love learning, so if confusing at times, I'm enjoying the process. Thanks again.
R