OK, been working to get my boolits just where I think I need them with alot of help from you guys and finally got to load some and shoot em. Problem is it appears I am getting signs of high pressure that worries me quite a bit. Here are the details.
Winchester Brass ( probably fired 2 -3 times
Fed 100 Primer
AA#7 Powder ( Started at 7.6 grs, went to 8.3 at .1 gr increments)
177 gr cast boolit ( actual weight ) from RCBS mold # 82067
BHN is approx 10.4
COL 1.130
Bore slugged at .403
Cast boolit sized at .405
Chrony did not work well so I do not have FPS ( too frigin cold )
Anyway , the primers appear to be flattening even at the starting load of 7.6 and continues the whole way thru the 8.3 load. Not any worse from begininning to end. When I went to reload the next batch with the load that appeared to shoot the most accurate ( 7.7 grs ) 2 of the ( 50 ) cases split wide open on the sides, from top to bottom, which I luckly caught after the bullets were seated and complete. (I use a progressive press so don't see them till they are done.) What am I doing wrong and how do I fix it ? I have been loading for over 25 years ( although new to casting ) and have never seen this before , I was seating a bit deeper on prior loads and thought maybe that was the problem so I seated them out a bit from 1.120( recommended) to 1.130 thinking that would help but to no avail. I am reading some accounts that the .40 is a caliber to be careful with on pressure issues but I never dreamed it would be this fussy. Any insite on this would be appreciated.