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Christchild · November 23, 2009, 12:36 PM

A faster burning, faster burn rate powder, burns faster. It builds pressure more quickly.

Say, if You use the same cartridge (in Your case, 9mm Luger), same bullet and bullet weight (115 grain HP), the faster burning powder AA#5 will build pressure faster than AA#7.

If You look at Your Load Data PDF You have posted, Max. Load #5 is 6.3 grains, generating 33,000 CUP (pressure), while it takes a Max. Load of 8.7 grains of AA#7 to generate the same amount of pressure. Slower powders, like AA#7 are better suited for the heavier bullets in Your 9mm cartridge.

Here's a little more Accurate Arms Load Data. Compare bullet weights, powder charges, velocities and pressures.

But if You notice, the AA#7 generates more velocity, because the powder burns behind the bullet longer, building pressure for a little while longer, while the bullet is still traveling down the barrel. But there is also a factor to be aware of... DO NOT use a powder that's even slower than the AA#7 in Your 9mm Cartridge, unless it's in Published, Up To Date Load Data. Slower Burning Powders, well, generate pressure more slowly. A slower Pistol Powder, like AA#9, is generally used in Heavier, "Magnum" Handgun/Pistol Cartridges, like .44 Magnum, for example. These kind of Heavier Cartridges have more Case Capacity and use Heavier Bullets. They need the slower powder to SAFELY push the heavier bullets. In less extreme cases, if You used a powder that's too slow for Your cartridge, You'll end up with CRAP Accuracy, and UNburned powder. In more "extreme" cases, Pressure Spikes can occur (NOT good), and You can damage/destroy Your firearm and/or injure/kill Yourself.

Always use Published, Current, Up To Date Load Data,and stay within those guidelines.

November 23, 2009, 12:36 PM	#5
Christchild Senior Member Join Date: June 19, 2009 Location: Loadbenchville, Bolt 02770 Posts: 544	A faster burning, faster burn rate powder, burns faster. It builds pressure more quickly. Say, if You use the same cartridge (in Your case, 9mm Luger), same bullet and bullet weight (115 grain HP), the faster burning powder AA#5 will build pressure faster than AA#7. If You look at Your Load Data PDF You have posted, Max. Load #5 is 6.3 grains, generating 33,000 CUP (pressure), while it takes a Max. Load of 8.7 grains of AA#7 to generate the same amount of pressure. Slower powders, like AA#7 are better suited for the heavier bullets in Your 9mm cartridge. Here's a little more Accurate Arms Load Data. Compare bullet weights, powder charges, velocities and pressures. But if You notice, the AA#7 generates more velocity, because the powder burns behind the bullet longer, building pressure for a little while longer, while the bullet is still traveling down the barrel. But there is also a factor to be aware of... DO NOT use a powder that's even slower than the AA#7 in Your 9mm Cartridge, unless it's in Published, Up To Date Load Data. Slower Burning Powders, well, generate pressure more slowly. A slower Pistol Powder, like AA#9, is generally used in Heavier, "Magnum" Handgun/Pistol Cartridges, like .44 Magnum, for example. These kind of Heavier Cartridges have more Case Capacity and use Heavier Bullets. They need the slower powder to SAFELY push the heavier bullets. In less extreme cases, if You used a powder that's too slow for Your cartridge, You'll end up with CRAP Accuracy, and UNburned powder. In more "extreme" cases, Pressure Spikes can occur (NOT good), and You can damage/destroy Your firearm and/or injure/kill Yourself. Always use Published, Current, Up To Date Load Data,and stay within those guidelines.