I recently chronographed some loads of Herco in a 686 six inch 357 mag, the loads came from Alliant directly. As 6.8 gr to max of 7.5 gr.
I settled at 7.3 gr with a cast performance 158 gr rnfp, new Winchester brass and Cci 500 primer at a velocity of 1190 give or take . I loaded 50 of those after I had tried several cylinder fulls to chrono, I let my wife shoot that 50 while I was chronoing another revolver and different powder.
I noticed when I was watching her shoot , “she was tearing a pop can up at 25 yds”, that the end of the cylinder looked like it had smeared lead around it ..
Upon investigation, I see that those 50 rounds had indeed already had the start of a small flame cut on the top strap in that short of a time , and the cylinder end did indeed have melted lead around the throats.The forcing cone appears ok , as best I could tell..
I’ve mostly used sr 7625 and 4756 up to this point , but was investigating different powder, because I’m down to my last 8 pounds of 4756 , and it’s my preferred 44 mag mid range load, in my 629. So I Know this powder is the culprit, because that flame cut was never there before..
Has anyone else had this trouble with Herco ? Or is something else going on?