.38 Special 158 grain LRN/SWC Crimp

Does anyone have a dimension for crimp that they use for .38 Special when loaded with 158 grain LRN / SWC ?

I noticed when people recommend load data for .45 ACP we mention a crimp diameter. I don't hear abut crimp diameter much when reading through the conversations about .38 Special. People say to crimp it by what looks good. For the most part, that's what I've been doing. 

I noticed the brass after being sized was measuring .372'' and when it was crimped it was .368''. I will be range testing the one box of ammunition I made yesterday. If it shoots good I'll leave the crimp alone, but if it doesn't I'll probably tighten the crimp some. But I suspect I'm in the right area.

I decided to keep things consistent by roll crimping my HBWC loads and my SWC loads. I use a Brazos coated 158 SWC, which has a crimp groove. Haven't shot enough to determine its accuracy, though.

EDIT: The reason I haven't tested much for accuracy is because I'm not sure how much DR I'll shoot over the next couple years, with CMP service revolver available now. I'm pretty much only loading HBWCs now.

Dave

This is a factory 130 grain FMJ.  


This is a factory 148 WC.  Note the similarities in crimp.  Both are roll.  Try to duplicate these.  I’m sure much of the inaccuracy of 38 ammo is due to crimp.

The crimp used worked good. I might even tighten it up another thousandth or two. Good groups, shots were on call.

IN 38 SPL I'VE FOUND THE BEST 50 YD ACCURACY CAME FROM USING THE REDDING PROFILE CRIMP DIE. IT'S A COMBINATION ROLL AND TAPER CRIMP. THIS WAS FOR LEAD BULLETS ONLY. 148GR AND UP. IT REALLY HELPS IN THE MDL 52.