Reloading Manual Differences

[dan1bett]

Good Morning:

I'm still the New Guy and I am learning how to use the INGO web site. I hope this is the right place for this.

I've been active with weapons my entire life.
I have 4 Sons, 2 Daughters and 7 Grandchildren
to date. Of which all but 3 Grandbaby's are
very active in outdoor sports.
We are familiar with most weapons for North
American game; .17 to .375 H&H
.410 to 10ga
Archery, Traditional to Modern
Military, Defense and Offense

In an effort to shoot more and have even more fun, we have progressed to 'Reloading'.

Individually, we are of average knowledge with our own favorites. However, as a group we can usally figure anything out.

We have ran into one question that we can not find an answer to. Who holds presidence when looking for reloading formulas?

Powder Manufacturing Manuals
or
Bullet Manufacturing Manuals
example

.357 Mag Hornady XTP
H-110 Hodgden Powder

Same Powder amount, Same Bullet weight in both manuals
Different Velocities and different Pressures

Respectfully

Dan

ps. I like everyones little sayings, so here is mine,

If You don't know your Rights, You don't have any.

 

[buford t justice]

As to your discrepancy of the velocity of the two manuals,they are posibly using different guns and or different barrel lengths.
And it is always my practice to consult more than one manual for a particular loading.
also one batch of any one powder will produce different pressures than another batch of the same.
The old gent I learned most from would work up loads and when he found a good one he would go back to the gun shop and buy all of the powder with the same lot number that they had.

 

[buford t justice]

O yea and to

 

[rimfire_crazed]

You absolutely need to consult multiple sources. Pick the data that is closest to your weapon's configuration and then work up your load based on that data.

If you are shooting a 20" barreled levergun and you have load data that is developed in either a 18.5" barreled rifle or a 16" gas gun, use the data from the 18.5", etc..

You'll likely get to max loads without signs of pressure if you're matching components and load data. Your most accurate load will be found somewhere along the way.

Once you're comfortable with loading and understand the signs of overpressure, you'll become more comfortable substituting components and interpolating data for your needs.

Welcome to Ingo.

 

[XtremeVel]

Same Powder amount, Same Bullet weight in both manuals
Different Velocities and different Pressures
.

The above posters nailed it as to why that difference could very easily be possible.

There will be times you will find a difference in the data itself from one source to another. In data, I mean the min/max charge and a difference in the bullets OAL.

Thats a great example why you want to start back of max and work up the new load thru your gun. What might be perfectly safe in one gun might start to show signs of pressure in another.

Referencing multilpe sources is a great idea. I have a stack of cheap walmart index cards on my bench. Whenever I try something new, I will note on a card the source, min and max charge, and also the listed OAL. Sometimes depending on how common the bullet is, I might have 4-5 cards layed out. I will then study the info and come up with something middle of the road as a starting point for the charge. Just remember to note not all souces list both starting and max... if they only list (1), be aware it could very well be the max... Alliants manual comes to mind... They list max only and it's up to you to reduce by 10% as a starting point.

 

[indyjohn]

Dan, the way I got around this problem was a $99 Chronograph. IMHO, if you're going to reload numerous calibers, and bullet weights and you know the distances you want to shoot and velocities it will take given bullet weight to get there, the chrono is an extremely useful tool. It takes the mfg's discrepancy right out of the equation.

 

[U.S. Patriot]

When I started reloading 9mm I first looked in my Lyman manual. Then I went onto Hodgdons website and looked at their load data. That's what I'm using for my loads. The Lyman manual did not have a load for 115 grain FMJ bullets which I'm using for my target reloads. So far all my reloads have functioned better then I expected. The Lyman manual is good for case OAL, max OAL, and other aspects.

 

[msd]

XtremeVel hit the nail on the head. You can referncee several manuals but it's best to reduce 10% and work up, unless manuals note otherwise. I've got load data that calls for only 3% reduction due to pressures.