Variations in Manuals

No consern at all. Rifle shoots well with no pressure signs, just keep jerking that trigger

AJC1 said:

No consern at all. Rifle shoots well with no pressure signs, just keep jerking that trigger

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Smoothly pressing would be better.

I see the powder charge difference between the Lee manual and Hornaday manual in other calibers.
In older guns I'd stick with the lower powder charges.
With your AR it should be OK.

Is there different bullet seating depths between the 2 books? A side note i rarely use the Lee one. I mostly use Lyman's 50th and their 3rd and 4th cast editions.

I ran into the same thing with 357 magnum loads. The Lee manual doesn’t put the primer used in the load data table. The cartridge illustration at the beginning of the section specified small rifle primer for 223. It specified small pistol primer for 357 mag, but most recipes specified Small Pistol Magnum primers. I emailed Lee about the difference, and my assumption that their recipes spec’s small pistol primer rather than small pistol magnum. The reply I got was, “Your assumption is correct! Our recipes are with Small Pistol primers.”

Does the Hornady manual spec Small Rifle Magnum primers?

Lee doesn’t do any actual testing, they get it from other sources. Every manual will have slightly different results with the same components just due to manufacturers tolerances, testing methods, and the phase of the moon.

I personally use the Hornady manual most of the time unless it doesn't have the bullet I am using listed.

Here is Hodgdon’s data site.

https://www.hodgdonreloading.com/?_ga=2.46948967.1568341390.1644204118-299832460.1644204118

They have different loads than the OP’s other sources. It is the system. Of course, Hodgdon uses different bullets.

As said, Lee prints data that others have developed and the powders may have changed slightly since the Lee data was investigated.

I’ve seen this with some Western Powder data. As a new version of their manual is published, some of the max loads are reduced from one version to the next.

I like to consult several sources when I venture into a new cartridge or powder. This includes powder manufacturers’ data and bullet manufacturers’ data.

You got a bunch of fast good answers. Wish I had too many mag primers

I always try to look at multiple sources when doing a new load because of the inconsistencies between loading manuals. FWIW my lynman book shows a starting load of 24.3 and a max load of 27.0 for H335 and 55gr .223 with small rifle primers.

One thing to remember. When manufacturers test loads, they don't always work up to the absolute max safe load. They usually stop adding powder when they achieve the goals they are looking for. The max load listed in many manuals is simply the point where that manufacturer stopped testing.

Another manufacturer, using the same components, may push the envelope farther and determine that a heavier powder charge is perfectly safe.

jmr40 said:

One thing to remember. When manufacturers test loads, they don't always work up to the absolute max safe load. They usually stop adding powder when they achieve the goals they are looking for. The max load listed in many manuals is simply the point where that manufacturer stopped testing.

Another manufacturer, using the same components, may push the envelope farther and determine that a heavier powder charge is perfectly safe.

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This is the exact reason why I want listed test pressure. With lyman you know, with hornaday you guess. Pressure information let's us know if were pushing the limit or being stupid.

This question comes up often enough it might be nice to make the replies - especially @mdi 's links to Hornady, Sierra and Nosler's answers - part of the Wisdom sticky.

The question keeps coming up because some readers don't like the answers, or refuse to accept the truth. Complicating the issue is the wide variety of answers given.

Regardless of source, if the load data doesn’t list measured pressure ( not a ‘guess’ based on velocity), it’s incomplete or hearsay.

It comes up often because not all reloaders read every manual and spend half their life learning everything about reloading and interior ballistics. But, they still want to make ammo for their gun. I think it's a reasonable question for even a long time reloader to ask.

Everyone needs to remember, there was a time we were all new reloaders. We all know now, less than we will after another 20 years reloading.

Bazoo said:

It comes up often because not all reloaders read every manual and spend half their life learning everything about reloading and interior ballistics. But, they still want to make ammo for their gun. I think it's a reasonable question for even a long time reloader to ask.

Everyone needs to remember, there was a time we were all new reloaders. We all know now, less than we will after another 20 years reloading.

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Which is why it might be nice to have a sticky here: https://www.thehighroad.org/index.php?threads/reloading-library-of-wisdom.649184/

In the navy we would have a flow chart. You start with book load and apply modifications to the recipe as you go down. Only max charge reduce 10 percent. Use magnum primers reduce 2%..... and down the chart you go. There are charts with primers just like powder with nominal sizes and comparisons of power.

hdtramp said:

. . . without noticing any obvious signs of excessive pressure. Should I be concerned, and why is their such a difference in manuals?

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1) Good
2) No
3) because loading manuals are one of the very very few places most people see real, unfiltered, adulterated, unFauci'd DATA.

Data is real, and noisy. Intra-lab, test cell, powder batch, calibration routine, and operator moustache quotient variation all produce offsets in data.

I have a rifle that will tolerate ~50% of min-max book charge in most listed powders, and I own manuals that consistently list max charges 10-15% higher than others.

This is why we start low, and work up.

edwardware said:

unFauci'd DATA.

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Really necessary ??

This discussion reminds me of the periodic scale discussion here.

Which is better / correct? X drops a charge that is 3 gn heavier than B and they are both calibrated to deliver the same charge. WHICH IS CORRECT?
If you use two scales, there is bound to be cal / drift problems.

I use one manual, Lyman's current. If the bullet isn't exactly the same as what I have on hand I use the closest and / or interpolate the load. Never had a problem in nearly 40 yrs.

I have more than one manual, but have found the Lyman to be the one that most matches my shooting. I've used others but only if it lists a powder / bullet combo not in Lyman. I don't shoot a lot of different calibers.

BTW; my Pacific powder balance, cal'd by weights down to 1 grain, is my "gold standard" by which I judge my digital scale.

45 long said:

Really necessary ??

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Maybe not, but very descriptive (everyone knows the meaning)...

PWC said:

This discussion reminds me of the periodic scale discussion here.

Which is better / correct? X drops a charge that is 3 gn heavier than B and they are both calibrated to deliver the same charge. WHICH IS CORRECT?
If you use two scales, there is bound to be cal / drift problems.

I use one manual, Lyman's current. If the bullet isn't exactly the same as what I have on hand I use the closest and / or interpolate the load. Never had a problem in nearly 40 yrs.

I have more than one manual, but have found the Lyman to be the one that most matches my shooting. I've used others but only if it lists a powder / bullet combo not in Lyman. I don't shoot a lot of different calibers.

BTW; my Pacific powder balance, cal'd by weights down to 1 grain, is my "gold standard" by which I judge my digital scale.

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And the Lee autoprime discussion which always concludes with a statement to the effect that Richard Lee was refused testing materials by Federal.

Sierra, Hornady, Alliant, Hodgdon, Lyman et. al. all say their results are based on their testing and is only accurate within those constraints.

"Good question. First of all, we need to understand that reloading manuals are not carved in stone. Think of a reloading manual as a report. In essence, a reloading manual says, “We tried this particular component combination, and these are the results we obtained.” When you duplicate the load shown in a manual, you’re using a different rifle (even if it is the same make, model, and caliber), a different lot of powder (even if it is the same brand and type), a different lot of cases (even if they are from the same manufacturer, etc.), a different lot of, well… you get the idea. There are an amazing number of variables that affect any load combination. With the difference in the manuals, you’re just seeing first hand examples. Again, start low, and work your load up." - Sierra

"The size of the specific firearm chamber, throat dimensions, seating depth, bullet profile, propellant variances and crimping depth can all contribute to variations in load data. The data found in the Hornady loading manual represents actual results derived in the Hornady Ballistics Laboratory. Hornady recommends that reloaders always start with the “starting load” and work up cautiously until they achieve the performance they're looking for. If pressure signs become evident, stop immediately and reduce the load or try another propellant." - Hornady

"Several factors contribute to variations in data. The hardness of different bullets affect how they obdurate to the bore which affects the drag. Different barrels can produce different results, test barrel vs. production barrel. Different lots of powder may produce variations, and different pressure measuring techniques may produce different results. All reloading data is a guide not an absolute and the reason it is recommended to start low and work up." - Nosler

In related news, "Why don’t I get the same velocities listed in your manual from my rifle?
Nosler® uses minimum spec. test barrels which are equivalent to the best custom barrels. These barrels produce maximum pressures and velocities so the data will be safe in any barrel. Factory production barrels are generally slightly looser and may or may not generate the same velocities at equal pressure. We have seen identical factory barrels vary as much as 150fps with the same load. Also, it is common for us to use 26” barrels (especially in magnum cartridges) to shoot load data which will also produce higher velocities when compared to 22” and 24” barrels." - Nosler

"The information displayed on this site, including ballistic data, was derived from tightly controlled laboratory conditions. This information and data may vary considerably depending on many factors, including the components used, component assembly, the type of firearm used, reloading techniques, safety precautions practiced, etc." - Alliant

I like Nosler's explanation about using tighter than industry-standard custom barrels.