357 Mag Winchester PDX-1 125gr JHP

[RDub01]

Cartridge is from Ammo Manufacture:  Winchester .357 Mag PDX-1
Muzzle Velocity; Advertised:   1325 fps  (No barrel length mentioned)
Actual Instrumental Velocity:   2½" barrel; 1162 fps.
                                             4" barrel; 1222 fps.  39°F
Muzzle Energy; Advertised:    487 ft/lbs





Brass Make/Headstamp:  Winchester 357 MAG
Bullet Make/Weight/Contruction/Info:  Winchester 125grs  Bonded JHP; .3571" dia;  .557" long.
Actual Weight:     124.3grs.





Crimp diameter:
C.O.A.L.:    1.571"
Primer:  Winchester WSP
Case: Nickel
Powder Description/Positive ID/Type/Charge Weight:  Medium Flake; 9.5grs.







Wasn't expecting this flake powder to be in these rounds, but if these are mostly intended to be used in short barrel revolvers it makes sense. Better than trying to burn a whole bunch of ball powder in a few inches of barrel.

[The_Shadow]

I don't have any data to support this, but it could be the new UNEQUAL powder from IMR.  It is used in 38 S&W but no data shown for 357 Mag (yet)

[RDub01]

I had 'heard' that IMR pulled Unequal off the market.  Something about it caused some concern. I can't find any mention or listing of Unequal in IMR's online data site. I didn't check the shotshell data..  Might be a non-canister variant of some sort.