Chronicles of working-up loads for my 357-SIG

357-SIG: A General Purpose Load: Load GP#1 .. 9.0 grs of AA #5 stays within Mfg. recommended Max Load.

357-SIG: A Paper Target Load: Load PT#1

Two useful loads that work for me. Load GP#1 makes use of Re-sized bullets to 0.3558” diameter.  This allows me to stock 38/357 125gr FP bullets and use them to generate loads for: 38 special, 357 Magnum and 357 SIG. A lesson from; “Lean Manufacturing – Flexible Inventory.”

Manufacturers load ranges for 357-SIG; Hodgdon and Accurate Arms .. check their web sites.Future Plans:

1) 357 SIG: Next step is to Re-Size 38 Special, 158gr SWC bullets to 0.3558 and verify velocity. If all is ok this will be PT Load #2

2) 9mm Luger; develop a re-sizing process for 0.357” diameter bullets to 0.355”.

Ideas are to use a two-step process: 0.357” to 0.356”, then 0.356” to 0.355”. A one step resizing from 0.357” to 0.355” will be tried.

Outline of test plan that determined my optimal loading from me using SIG 357 Semi-auto Pistols.

The Basic plan is to use my previous load as a baseline, test number 4. Setting up these experiments is fine when you have total control, but using a public indoor range, forces one to make accommodations and concessions.

The tables chronicle the test sequences and variables of empirical data and results. The relative feelings experienced during the shooting and general satisfaction with said results, are a major factor to consider.

All range shooting is Free-Hand shooting. no pistol rest. So natural variability is built in .. My quest is to find what works for me.

Dual, side by side targets set at three distances for each test. Sig P229S – Five shots at each target. An eight by three matrix requires: 8x3x10 = 240 rounds and 8x2x3 = 48 targets. Prior to a test run seventeen round of Blazer commercial ammo was shot to warm up the pistol (when shot at different times/days) Velocity averages are 10 shots over the chronograph, prior to shooting the targets.