[Kelly J]

I had a bad experience of a Bullet not holding in a S&W 625-9 Mountain Gun 4" Barrel with a moderate Velocity load, 10.5 Gns HS-6 Powder under a 250 GR LRNFP Bullet, Range brass and Winchester LP Primers, the load was seated to a COL of 1.595. Published Velocity of 946 FPS with a Published Pressure of 13,300. The Cases were not trimmed to any length, which admittedly is part of the problem. I use a Dillon Square Deal B Auto Progressive Press each station is independently adjustable. I talked to my Bullet Supplier and He Suggested that I resize with a 45 ACP die to reduce the case Dimension, where the bullet will be seated, there by increasing the tension on the Bullet, It sounded plausible so I tried it but with a hitch, I full length resized the cases with the normal 45 Colt Die then I partial resized with the 45 ACP die to a depth of 3/8 inch. Then I put the unprimed case in the Powder/Primmer/Flair Station, (the expander dimention is .4478”), and proceeded as normal, loading the lead RNFP Bullets and crimping the dummy rounds to check results.

Results case Dimension after resizing 45 Colt dies .470"
Case dimension after partial resizing 45 ACP Die.466"
Case Dimension after Seating Bullet.472"
Bullet Dia. before loading .452" after breakdown of dummy load .452" and showing good drag marks of case from the round loaded with the 45 ACP resize die used a kinetic bullet puller.
The crimp is a combination taper/Roll Crimp as this is the design of the crimp die.

The crimp on the rounds that did not hold was a ROLL CRIMP for clarification.

Prime Question: Your feedback on this process, Your thoughts on the partial resize with the 45 ACP die, What if I used the 45 ACP Die to full length resize the case eliminating the first step and the extra step of partial resizing, and would I gain any extra holding power by using the 45 ACP Crimp die instead of the regular 45 Colt Crimp Die, Finally do you think this would affect the accuracy as the Base of the case and the loaded Diameter of the case mouth will be as a normal dimension load with only the middle of the case being undersize.