Missouri 125 grain SWC ... HAP 125 ... Thoughts on charge and OAL?
To determine Max OAL, you would need to use the barrel until dummy rounds (no powder, no primer) dropped into the chamber freely with a "plonk" and spin without hitting the rifling.
Then to determine Working OAL, you would need to load the magazine with dummy rounds and release the slide without riding it. If Max OAL would not reliably feed and chamber dummy rounds, incrementally decrease the OAL by .005" until they do.
For Hornady 125 gr HAP, these were Max/Working OALs for various barrels and pistols I tested from "Barrel vs Max/Working OAL ..." thread -
https://www.thehighroad.org/index.p...col-for-reference.848462/page-2#post-12249361
- Glock 22, KKM 40-9 conversion barrel - Hornady 125 gr HAP: 1.125"
- M&P Shield - Hornady 125 gr HAP: 1.120"
- Glock 22, Tactical Kinetics 40-9 conversion barrel - Hornady 125 gr HAP: 1.070"
- Glock 23, Lone Wolf 40-9 conversion barrel - Hornady 125 gr HAP: 1.045"
For SWC (which is usually made from RN profile with non-feed ramp bump contact areas removed), most load with thumbnail thickness of shoulder above the case mouth to determine the OAL. For MBC 124 gr SWC, that's 1.045".
Bullseye loads? ... Trail Boss, Titegroup, HP-38, Universal, Unique, WSF, and Power Pistol ...
Dan Wesson PM9 ... original springs. Velocities as slow as possible consistent with good accuracy and cycling are the goal.
I am reading bullseye match loads? A seasoned bullseye match shooting mentor taught me to reload and I would started with longest Max/Working OAL and most conservative published load data for initial powder work up. If start charges produced accuracy, I would "work down/download" powder charges until accuracy dropped or slide would not reliably cycle. Then I would incrementally decrease OAL by .005" to see if groups got smaller. (Of course, I would keep SWC OAL same for reliable feeding/chambering)
For slower velocity target loads, faster burning powders tend to burn more efficiently at lower charges to produce consistent enough chamber pressure build/max average pressures for accuracy. So I would suggest testing faster burning than W231/HP-38 which means using HP-38 and Titegroup. (Bulky Trail Boss was meant for filling larger case volume .38 Special and Hodgdon doesn't show load data for 9mm 124/125 gr and likely not suitable for smaller case volume 9mm, especially for SWC/JHP bullets that gets seated deeper into the case neck)
Hodgdon load data -
https://www.hodgdonreloading.com/reloading-data-center
- 9mm 125 gr Hornady HAP HP-38 COL 1.069" Start 2.8 gr (753 fps) - Max 3.3 gr (876 fps)
- 9mm 125 gr Hornady HAP Titegroup COL 1.069" Start 2.8 gr (816 fps) - Max 3.2 gr (930 fps)
- 9mm 125 gr Lead CN HP-38 COL 1.125" Start 3.9 gr (1,009 fps) - Max 4.4 gr (1,086 fps)
- 9mm 125 gr Lead CN Titegroup COL 1.125" Start 3.6 gr (1,002 fps) - Max 4.0 gr (1,096 fps)
If Max/Working OAL for your PM9 is longer than published OAL, I would reference start charges and work down until accuracy/slide cycling is not consistent. If Max/Working OAL is shorter than published, I would consider reducing start charges by .2-.3 gr and work down.