Why so much variation in reloading data - who to believe?

[AJMD429]

240 grain jacketed .44 Mag bullet H-2400 powder

Lee Modern Reloading 2nd edition - "start with" 17.0 grains - "never exceed" 18.7 grains

Sierra Reloading Guide (1971 ) lists three loads for rifle - 19.7 for 1500fps, 21.1 for 1600 fps, and 22.6 "max" for 1700 fps.

Why the big difference? More lawyers these days? Powders changing over the years?

I don't think it is that Lee is "pistol" data, because Sierra's pistol loads are 19.5 through 23.3 grains.

I see that with lots of loading data. I can understand slight variations, but geez - you'd be past the "never exceed" level just with starting the Sierra's recommendations.

[Chuck 100 yd]

Depends on the bullet. Sierras .44 bullets are .4295, Speers .430 , others, who knows! Also test barrels vary in diameter.
It is best to start low and work up.
My friend in Montana used to shoot a load in his .300 Mag. that was a full 4 gr. over Sierras book max and no pressure signs at all.

[Old Savage]

That is why you are always on your own ultimately about what is safe.

[Terry Murbach]

THE QUESTION IS NOT--NOT !!!--WHY THERE IS " SO MUCH DIFFERENCE " IN LOADING DATA, THE REAL QUESTION IS HOW IT CAN BE SO CLOSE TOGETHER CONSIDERING EVERYTHING USED IN THE TESTING WAS DIFFERENT FROM WHAT EVERYONE ELSE WAS USING ???
DIFFERENT GUN.
DIFFERENT PRIMERS.
DIFFERENT BULLETS.
DIFFERENT PROPELLENT LOTS.
DIFFERENT TEMPERATURE.
DIFFERENT HUMIDITY.
ETC.
ETC.
ETC.
ETC.
ETC.
ETC....
AD INFINITUM TO A THOUSAND DECIMAL POINTS.
THIS IS EXACTLY AND PRECISELY WHY YOU CANNOT TRUST ANY INTERNET DATA TO BE CORRECT OR EVEN SAFE IN YOUR GUN AND ASKING '"I NEED A LOAD FOR MY XYZ " IS EXACTLY THE WRONG QUESTION TO ASK.
I NEVER LOAD THE FIRST TEST CARTRIDGE WITHOUT CONSULTING SEVEN [7] PRINTED LOADING DATA SOURCES. THE HIGHEST STARTING LOAD IS DISCARDED, THE LOWEST IS DISCARDED, THE AVERAGE OF FIVE HAS ALWAYS WORKED, SO FAR. IF THE PROPELLENT IS ALL OVER THE MAP GETTING TEN OR MORE SOURCES IS A FAR BETTER AND SAFER IDEA.
INCIDENTLY, I DO NOT CONSIDER ANY PROPELLENT COMPANY'S INTERNET LOADING DATA TO BE SAFE AS IT IS TOO EASILY HACKED. MAKE NO MISTAKE ABOUT THIS NO MATTER WHAT THOSE PROPELLENT COMPANIES MAY CLAIM.

[O.S.O.K.]

You picked a powder that has changed over this time period - 2400 now burns much more completely than it did previously. The reason that the 44 Mag loads are now less but you should notice that the velocities are the same with less powder.

Just updates - that's why we need to buy new manuals from time to time. Something I've been putting off myself - hard to spend $30 on something that you already have....

[J Miller]

What Terry says is dead nuts on. No two variables are the same, ever.

What O.S.O.K. says is also true. The newer 2400 does seem to burn cleaner and more completely. However I haven't noticed any difference in performance other than that.

Joe

[Hobie]

Amen Terry, amen...

PS - Several years ago, Yance might remember, we were discussing the "differences" (or lack thereof) between H110 and W296. I went through every manual I could lay my hands on looking at the data presented where both powders were shown for the same cartridge, same bullet and primer by the same manual author/publisher. The average difference was actually only 1.4% (IIRC) but the greatest difference was about 10%. It was particularly important because H110/W296 (actually the same powder but in different lots with different packaging) has a relatively narrow range of safe charge weights with most recommending starter loads no less than 3-10% less than the maximum. It was interesting, at least to me, that there could be a 10% difference in the max charges.

[JimT]

You might also take a look at this: http://www.leverguns.com/articles/ballisticians.htm

[chadbr]

For me the question has always been "how can I detect unsafe pressures without $50K in detection equipment??"

I've never seen a definitive "things to look for" list. I've seen several -- "If you see this -- you're in trouble!" But then they always seem to say something like "techniques for detecting unsafe pressures are beyond the scope of the article", etc.

I've read about flowing primers - but never seen a picture of it... That's about all I know.

As for me -- I stay on the low side of the average for all published data I can find - but I'm a (insert your favorite feminine insult here)

[Griff]

What terry & OSOK said. And I'm behind in my manual updating also.

[marlinman93]

After you've used a number of different manuals for loading data, you'll come up with one that consistently is closer and safer than all others. I wont reccommend a certain manual, as I've got a few that are always good choices. I have found that there are also some in my library that almost never get opened, as they notoriously list loads that I've found to be either unsafe or really pushing the limits to the point of hard extraction and flattened primers.
Find that one book, and use it first once you feel comfortable with the loads it references.-Vall

[45Jack]

What they said...
Plus, in my limited experience with max loads it seems best accuracy and max velocity don't necessarily exist together.
I'd go with the most accurate load over a few more fps.

[O.S.O.K.]

For me the question has always been "how can I detect unsafe pressures without $50K in detection equipment??"

I've never seen a definitive "things to look for" list. I've seen several -- "If you see this -- you're in trouble!" But then they always seem to say something like "techniques for detecting unsafe pressures are beyond the scope of the article", etc.

I've read about flowing primers - but never seen a picture of it... That's about all I know.

As for me -- I stay on the low side of the average for all published data I can find - but I'm a (insert your favorite feminine insult here)

The only reliable method that I am aware of is to measure case head diameters of fired factory ammo and then compare to your handload's after firing. Obviously, that means starting well below max and working up and measuring the case heads - and you have to use the same brand of brass - and it doesn't hurt to weigh them to be sure they're the same either.

Got that from Dave Scovill in Handloader or Rifle IIRC.