Max 9mm Load Question

I've seen Hogdon's published max load data that describes 115 JHP Titegroup as 4.8 grains, 4" bbl.   My Speer manual has its max at 4.5 grains, same bullet, COL and bbl. length.  I know I must err on the side of caution, but is there a reason for such a large discrepancy?   My 986 likes the hotter loads but I hesitate to exceed 4.5.

Bigtrout wrote:I've seen Hogdon's published max load data that describes 115 JHP Titegroup as 4.8 grains, 4" bbl.   My Speer manual has its max at 4.5 grains, same bullet, COL and bbl. length.  I know I must err on the side of caution, but is there a reason for such a large discrepancy?   My 986 likes the hotter loads but I hesitate to exceed 4.5.

Lawyers: Grab an older re-loading manual and all of the "safe" loads will be higher. They really are safe loads but lawyers started getting involved and the new SAMMI/CYA loads are all that they will publish.

Not just the lawyers.  Some of those old loads were stout.  When they finally tested them they were found to be just way too hot.  Also powders have changed through the years.  The Unique we get today isn't quite the same.  It isn't even made in the same plant anymore.

Elmer Keith just rolled over....

sheesh...

Lawyers yes but todays pressure reading equipment is sooo much better than the old pressure cup method...

Ken Waters is also rolling his eyes.

Not lawyers. Old data was done with a copper plug and the amount the plug was crushed determined the pressure. Not that accurate, but it was all they had.
Now, the labs get a real-time pressure trace showing every spike and anomaly. SAAMI has now defined at least three different statistical pressure measurements loads have to meet.
Using current test procedures, it was found that many of the old "pet loads" were 10-25ksi over pressure limits. 
Next, unless you have the same gun, the same lot of powder, the exact same bullets (manufacture and, often, the same lot number off the same swaging die) at the exact same COL, using the same cases and primers, how can you expect to get the same performance?
It's in the details, and the details aren't the same.

You might be able to get more velocity with Alliant Power Pistol, if you can find some. You can get over 1,200 fps with some loads in 9mm. My 9mm pistols like a velocity of about 1,140 fps.

BE Mike wrote:You might be able to get more velocity with Alliant Power Pistol, if you can find some. You can get over 1,200 fps with some loads in 9mm. My 9mm pistols like a velocity of about 1,140 fps.

My velocity increase is obtained with BE-86 giving 1200+ fps slightly above mid-range.  I believe the max published by Alliant is 6.3 for 115 GD JHP yielding 1238 fps.  The max TG load I have used in my 986 is 4.6 resulting in 8 of 10 rounds grouping 3/4" c to c at 25 yds. (manual rest, no chrono), and never hotter than 4.4 in my RO9, which prefers TG's lower velocity.