I just got some Win 572 powder and I'm looking for load information. I looked into the SAAMI manual and Hodgdon data. Hodgdon gives info for the XTP bullet with a 4" barrel. What confuses me (it's not hard to do) is why the max load shows velocity under SAAMI max and pressure under SAAMI max. I will use a chrono and stay under SAAMI maximum fps. I'll run a few different loads and look for the one with the tightest group. It's not that I want to use the maximum loads, it's that I am trying to understand them. I'm sure the powder manufacturers could give us more information, if it wasn't for their lawyers.
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Looking for the maximum load with 572
- Thread starter Wheeljack
- Start date
I just got some Win 572 powder and I'm looking for load information. I looked into the SAAMI manual and Hodgdon data. Hodgdon gives info for the XTP bullet with a 4" barrel. What confuses me (it's not hard to do) is why the max load shows velocity under SAAMI max and pressure under SAAMI max. I will use a chrono and stay under SAAMI maximum fps. I'll run a few different loads and look for the one with the tightest group. It's not that I want to use the maximum loads, it's that I am trying to understand them. I'm sure the powder manufacturers could give us more information, if it wasn't for their lawyers.
I would stay within the powder manufacturers maximum limit.
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I would stay within the powder manufacturers maximum limit.
. . . ^^ Yep. ^^
Load data is - for the most part - a starting point in most handloading situations. Using it as a guideline for max loads is secondary. Try not to get too wrapped up in the pressure/velocity data. Do your own thing and load safe.
The max is whatever is given in your manual for the specific bullet weight in whatever cartridge you're loading. Max loads in manuals are not arrived at by guessing. Load data shows pressures and velocities arrived at via testing with specific components and test firearm and conditions on the day of the test only.
In any case, neither the bullet shape or barrel length matters. The only thing that does matter is the bullet weight and calibre/cartridge.
Using a chronograph makes no difference either. Nor does velocity make much difference. Pressure does though and a chronograph tells you nothing about that.
SAAMI does give a max velocity. They give a max pressure at a given velocity. And they're averages. So is load data in manuals.
Anyway, the Hodgdon 147 grain XTP Win 572 data is what they found. Isn't necessarily anywhere near SAAMI max pressures for a particular cartridge and bullet weight. SAAMI max pressure for 9mm is 35,001 PSI. The Hodgdon load isn't far under that to still be a standard 9mm load vs a +P that has a max pressure of 38,500 PSI.
"...their lawyers..." Have nothing to do with it.
In any case, neither the bullet shape or barrel length matters. The only thing that does matter is the bullet weight and calibre/cartridge.
Using a chronograph makes no difference either. Nor does velocity make much difference. Pressure does though and a chronograph tells you nothing about that.
SAAMI does give a max velocity. They give a max pressure at a given velocity. And they're averages. So is load data in manuals.
Anyway, the Hodgdon 147 grain XTP Win 572 data is what they found. Isn't necessarily anywhere near SAAMI max pressures for a particular cartridge and bullet weight. SAAMI max pressure for 9mm is 35,001 PSI. The Hodgdon load isn't far under that to still be a standard 9mm load vs a +P that has a max pressure of 38,500 PSI.
"...their lawyers..." Have nothing to do with it.
Just remember... chambers / throats and leade's can be completely different from one manufacturer to the next.
Is your handgun a loosely, chambers everything handgun.. or a tight min. spec'd match gun ?
IE... minimum v. maximum chamber specs.
So, IMHO, the listed "Max" is safe in all Min. / Max. SAMMI chambers.... ( allowing for min. / max. chamber pressure differences.
Is your handgun a loosely, chambers everything handgun.. or a tight min. spec'd match gun ?
IE... minimum v. maximum chamber specs.
So, IMHO, the listed "Max" is safe in all Min. / Max. SAMMI chambers.... ( allowing for min. / max. chamber pressure differences.