The Firearms Forum banner

How Do the Power Mfg Determine Bottom End of Powder Range?

813 views 5 replies 6 participants last post by  noylj 
#1 ·
I just ran some N320 loads in my 9mm 1911 with 115gr coated lead from 3.9gr down to 3.4gr looking for the softest possible load for steel challenge. VV list 3.9gr as the "minimum". What criteria does a powder manufacturer use to determine the minimum load? Chamber pressure, velocity, group size? Guns actually cycled down to 3.4gr, but we tried 3.5gr at a club match and it's a no-go with a few stove pipes. I'm going to make enough 3.6 and 3.7 for a good test and see which my wife can cycle reliably. I also need to buy a low spring weight kit from Wolff to see if that helps with the lesser loads. Back to the original question - anyone have a good idea of the criteria?
 
#3 · (Edited)
I encourage you to stay with published data. Ignition and pressures can become erratic on the low end. There have also been reports of detonation when tiny amounts of fast burning powders are used in large volume black powder era cases, destroying firearms and injuring shooters.

I know your 9X19 is not in the same league as a 45 LC. For the safety of your wife, stay with tested published data.

To answer your question "How". Loads are tested in a laboratory in pressure test barrels. Velocities and pressure curves are recorded. Only safe results are published for consumer use.
 
#4 ·
I agree that you should stay with listed starting loads.

If it is a recoil issue I suggest your wife (or you) are not practicing enough for the recoil to become second nature. Women are not the lesser sex when it comes to shooting even heavy recoiling guns. They can learn to overlook the recoil. Just practice more and the recoil sensitivity will subside over time.

LDBennett
 
#6 ·
3.9 max, drop by 10-12% and you get 3.4gn. Simple as that.
They are called STARTING loads and not MINIMUM loads.
Some manuals use a certain velocity for their starting loads. Some use a certain pressure. Most simply use the 10-12% reduction from MAX load as has been done for about 100 years. Old manuals generally ONLY showed MAX loads because EVERYONE knew to drop the MAX load by 10-12% for a starting load.
Unless you are shooting a hard to ignite powder that requires a certain pressure and heat to burn (see H110/296), you can drop from the starting load quite a bit. Basically, you may get a bullet lodged in the barrel is velocity goes below 500 fps.
If this wasn't true, Bullseye loads (NRA Precision Pistol) would not be what they are and they have worked successfully for about 80+ years.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top