Waiting on getting all my equipment in, so I'm reading up in the two books I have. I was comparing 9mm recipes from both the Hornady and Lyman books, and I'm confused on what I'm seeing.
The first picture below is from Lyman, and the second is from the Hornady book. I'm looking at the Power Pistol powder.
The Lyman book shows 5.9 grains = 1257 fps and 6.5 grains = 1409 fps.
For Hornady, 6.0 grains = only 1150 fps and 6.4 grains = 1200 fps.
Why is there such a discrepancy between the two recipes' velocity when it's the exact same powder with nearly identical weights, and both recipes are using the 115 gain XTP bullet?
Does the primer choice and/or case used make that much of a difference on velocity?
The first picture below is from Lyman, and the second is from the Hornady book. I'm looking at the Power Pistol powder.
The Lyman book shows 5.9 grains = 1257 fps and 6.5 grains = 1409 fps.
For Hornady, 6.0 grains = only 1150 fps and 6.4 grains = 1200 fps.
Why is there such a discrepancy between the two recipes' velocity when it's the exact same powder with nearly identical weights, and both recipes are using the 115 gain XTP bullet?
Does the primer choice and/or case used make that much of a difference on velocity?