IMR SR 4756 for 9mm question

[ExpatGator]

Hey folks. Hope someone out there can help me on this one. I just, last night, completed my first small batch of reloads. As mentioned in the subject line I was loading 9mm (115 gr. fmj), using 4.5 gr. of SR 4756. This is the minimal load from the Lyman manual. This recipe failed to fully cycle the action on my wife's Sig P239. I obviously need to heat this up a bit. Any suggestions or experiences that could help me determine, with a minimum of trial and error on my part, how much to increase the load? All suggestions are appreciated.

 

[Jim Watson]

The usual recommendation for a starting load is 10% under max. Lyman, for some reason, starts a lot lower. Here, 4.5 gr SR 4756 is 26% under their maximum of 6.2 grains and is only rated for 946 fps. That is just heavy bullet .380 performance and I am not surprised it will not function your wife's gun. The IMR maximum is 6.3 grains so there is no real difference in test data.

The greatest reduction I was able to get my P225 to run with for a beginner - using a different powder - was 12% under max.

Try 5.5 grains SR 4756.

 

[ExpatGator]

Jim,

Thanks for the quick and informative reply. I will take your advice and go to 5.5 gr. I was probably (obviously) being overly prudent seeing as this was my first attempt at reloading. Even with the failure to cycle it was cool to shoot something that I loaded and I got a first lesson to boot! Thanks again.