Lyman info wrong?

[pcking78]

  Just started reloading, bought the Lyman manual first, as suggested by some on this forum. It is very informative, however, for a 150 gr.  jacketed bullet for a 30-30, with IMR 3031, it suggests as the maximum load 28.5 grains!  That's not a typo on my part.  I noticed that amount was about the starting load according to the data that came with my Lee dies.  Also, according to the data on the IMR website, the starting load was 28.7 grs. Could someone please cross check this info in one of the older editions of the Lyman book and maybe any other manuels they have?  How could there be that much difference in suggested amounts?  Lee and IMR both list max loads around 31 or 32 grs. What gives?

[Catfish]

Pulled out an old 45 edition and it says max load of 29.5 gr. You might e-mail Lyman and ask them why they dropped the charge, but better to lite then to heavy. 

[Hooker]

My Hornady book shows that as a upper mid range load with a starting load of 26.6 and a max of 31.4.
I wouldn't call the Lyman book wrong , most likely they were shaving down some of their liability.


Pat

[pcking78]

   It's not just that their maximum load is less, it is what Lee and IMR give as a starting load!  So, according to one set of data, my load of 28.3 is near max, according to two others, it is not even a very good start. Now I know why so many of ya'll have chronographs, I guess it is the only way to tell if you have an effective load.

[FW Conch]

  PCKing, this is not an unusual situation. If we look @ all of the loading manuals & sources it soon becomes apparent that there is a broad range between them from minimums to maximums. This will not be the first time you will incounter this disparity. Reloading is not an exact science- it is a learned/acquired skill, or art. The disparity didn't bother me when I first started reloading, because I thought as long as I didn't exceed maximums, or go too high, I was being safe. Then I found out about "flashover" & "detonation" that can occur in some "slow burning powders" under some conditions. This made me angry, because I felt the reloading "gurus" were putting all the importance on high loads, when there were people out there blowing up guns useing loads that were "too low"! 

As you go forward, you will find 2 well known reloading sources that stress not going below recomended "minimums". These sources are also at the "low" end of the scale, almost accross the board. Everyone else warns- "Dont exceed "maximum" listed loads. If one book's "maximum" is another book's "minimum", is one of them wrong, or is it more "wealth" of information for us to draw upon?

I have come to believe that I would have to do something really dumb to blow up a "modern day" bolt action loading it too "hot". But I have myself witnessed barrels split from end to end by reloaders that didn't know about "detonation", loading "slow" powders too low.

Slow or fast when refering to gun powder is a "relitive" term, depending on what chambering is being loaded. Slow in one round is fast in another.

Different rifle actions have different strengths, handeling morepressure. You will find the 45/70 has three different loading levels-the old weak trapdoor, the lever action,& the modern strong action.

The best way to proceed, is to stay on this site & learn from all the experience that is here! Just be safe! I'll leave the "exact"  defination of that to the more experienced!  Luck - Jim

[jhalcott]

  I always use several manuals to decide where to START a reloading adventure. THEN the gun tells me what IT likes. Not all 150 grain bullets are the same and do NOT react the same with identical loads! The manuals are GUIDE LINES not bibles. Also ,people can make mistakes when putting things together.

[Larry Gibson]

Concur that manuals are guides.  The important parts of them are often overlooked.  If we read the Introduction To Data, particularly where it references Maximum Load Grains we find Lyman uses other things than just maximum psi to list their "maximum load".  Many simply do not read these parts of the manual and go to the load data and use the "maximum load" assuming it is safe.  Not saying that is the case here but too often it is.  The really important part to any manual is the instruction to work up loads. 

Larry Gibson

[necchi]

"The really important part to any manual is the instruction to work up loads."

Well said,
 I've only been loading a short time. And having a blast experimenting with different bullets and powders, it's really fun finding accurate loads.
 To date, I have found only 1 load that exceeded listed max for best accuracy (and that a wopping 2 tenths), and 1 one other that is right at max for best accuracy.
 Point is, all other bullet/charge combos that give me the best accuracy out of MY guns, has been found under listed max by standards set by the bullet makers, Nosler, Sierra, Hornady,,,
I also got the Lyman book at the urging of many here and other forums, but it's my least looked at book,  . I doo look at it, and DO check several other sources when I begin a load, but I've begun to learn what my guns like and can (with peace of mind) toss out some of the really low listings of powder charges.
 Sure, a guy can find an accurate load 2.5 grains under max if a node can be found there, but I'm not going to be happy with a slow moving bullet. I don't NEED max, but I do want some velocity and effectivness down range.

[Slowpoke Slim]

As has been stated by FW,

You will run into this kind of thing as you go along. I have both the 47th, and the 49th edition of the Lyman manual. The loads are the same in both. I also have the current (7th), and the 4th editons of the Hornady manual. The loads in both those manuals list 31.4 grs as max. My old Ideal manual #38 (circa 1951) does not list that bullet and powder combo to reference.

As I said, I never throw out a reloading manual...

 

If you look a little deeper into the texts, you will see that in this case, Lyman, has used a "Universal Receiver" as a test rifle, and Hornady has used a Winchester M94 rifle. I think this is where most of the disparagement comes from. I'm not suggesting that either manual is "wrong", or either company has been negligent in any way. What I'm saying is they are using different methods to derive their pressure data. Universal Receivers and pressure test barrels are expensive, far more so than using a regular test rifle. Some companies use only rifles, and some use a mix of each.

A "Universal Receiver", is basically a test block with a pressure barrel screwed into it. These pressure barrels are usually machined to minimum specs, with a chamber that would be found to be smaller in dimensions than your average Winchester model 94 lever gun. The pressure barrel has a pressure port machined into it whereby the actual pressure in the chamber itself can be measured. If I recall, there are 2 primary ways of doing this, but both have the end result of being able to directly measure the maximum pressure that occurred in that chamber.

A massed produced hunting rifle, in this case a Winchester 1894, may have many, many barrels cut with the same chambering reamer and tool setup. This can lead to some "generous" chamber dimensions.

When a rifle is used, sometimes a "strain gauge" is attached to the rifle, but usually it is the fired brass that is examined to "determine" how much pressure occurred in the chamber.

Both methods will work, but each "rifle" is it's own individual, with differing chamber and bore dimensions. This will lead to pressure differences between rifles. You will notice this yourself, if you start loading ammo for same caliber rifles.