Published discrepancies??

[Boomer686]

I'm a little bewildered.... looking at several sources I find discrepancies in what each of them list as a maximum load for a particular bullet. For example let's look at:

.40S&W 180gr Jacketed bullet using IMR 700X:

Speer Reloading Manual #14 pg 919: max load = 5.5gr @ 1020fps

Hodgdon Reloading site max load = 4.6gr @ 970fps
http://data.hodgdon.com/cartridge_load_1.asp

Hornady Reloading Manual #7th Edition offers no load
- - - - - - - - - -
or

.44 Mag 210gr Jacketed bullet using H110:

Speer #14 pg 952: max load = 27.5gr @ 1664 fps

Hodgdon site: max load = 27gr @ 1665fps

Hornady 7th Edition offers no load
- - - - - - - - - -
or

.45ACP 185gr Jacketed bullet using HS6:

Speer # 14 pg 970: max load 9.9gr @ 926fps

Hodgdon site: max load 9.5gr @ 996fps

Hornady 7th Edition pg 898 : max load 10.3gr @ 1050

Just wondering if I'm being paranoid about over-pressure ... and a little confused about who to trust with regards to the max load.

Regards,

 

[Lefty Dick]

Welcome to the wonderful world of reloading.

Read the section in the Speer manual about Ballisticians getting grey hair, it explains a lot of what you are befuddled about.

The short answer is this: every firearm is made diffrent, barrel dimensions, chamber dimensions, rifling style, and of course BBL length. Then all components differ from lot to lot, be it primers, bullets, and powder. And lastly even cases differ from lot to lot.

This is why you never start with any published maximum, in this case look at something mid range for the lower published data and work up looking for accuracy.

 

[RePete]

To figure out the differences (not descrepencies), just read what equipment was used and under what conditions the testing was done.

Pressure barrel vs gun, etc.

 

[stubblejumper]

Just wondering if I'm being paranoid about over-pressure ... and a little confused about who to trust with regards to the max load.

No two guns are alike so don't blindly trust anyone.

To figure out the differences (not descrepencies), just read what equipment was used and under what conditions the testing was done.

Even using identical components and under identical conditions,there will be differences.Powder,bullets and brass all vary somewhat from lot # to lot #,and no two barrels are exactly alike even if the make and model are the same.

 

[oldfart]

Welcome to the wonderful world of reloading.

Read the section in the Speer manual about Ballisticians getting grey hair, it explains a lot of what you are befuddled about.

The short answer is this: every firearm is made diffrent, barrel dimensions, chamber dimensions, rifling style, and of course BBL length. Then all components differ from lot to lot, be it primers, bullets, and powder. And lastly even cases differ from lot to lot.

This is why you never start with any published maximum, in this case look at something mid range for the lower published data and work up looking for accuracy.

To add to the above, i have 7 manuals. The barnes #3 first edition is full of errors. When i contacted barnes they sent me photo copies of corrections. I would have expected the later edition which supposedly had the corrections.

So dont trust everything you see in one manual.

Nosler Speer Hornady Sierria Lyman Hodgdon are all good.

 

[Boomer]

To add to the above, i have 7 manuals. The barnes #3 first edition is full of errors. When i contacted barnes they sent me photo copies of corrections. I would have expected the later edition which supposedly had the corrections.

So dont trust everything you see in one manual.

Nosler Speer Hornady Sierria Lyman Hodgdon are all good.

Over the years the only manuals I haven't found mistakes in is the Nosler and Hodgdon books. Sierra I'll give credit to fixing their errors and sending amendments out to those who have bought directly from them or to those who are on their mailing lists. I recall when they moved to their operation to their present location they had to allocate lower BC's to their bullets. Hornady not only makes mistakes, but repeats those mistakes in subsequent editions. I now have little faith in their data and check it against other sources. I have found that loads in the Barnes manuals can produce velocities that are higher than those published, but thus far are not dangerous in my rifles.

 

[stubblejumper]

I have found that loads in the Barnes manuals can produce velocities that are higher than those published, but thus far are not dangerous in my rifles.

Metal fatigue due to excessive chamber pressures takes time to become dangerous.

 

[slushee]

I have also been reading about how some manufacturers are covering their lightly padded behinds by reducing the max loads so that if something happens, they wont be held responsible.

I cannot confirm if that is a reality, but from what I read about on the net, quite a few ppl believe this.

 

[Lefty Dick]

I have also been reading about how some manufacturers are covering their lightly padded behinds by reducing the max loads so that if something happens, they wont be held responsible.

I cannot confirm if that is a reality, but from what I read about on the net, quite a few ppl believe this.

Perhaps believing that better pressure testing equipment, is making some old favorite loads look mighty on the high side of reasonable.

Or perhaps that over time the burn rates of propellents has changed a bit.

Of course the two above mentioned things will make the leagal eagles a lot more wary.

Or how bout the fact that with all the diffeerent variables and lot to lot diffrences in components, that diffrences do and will exist.