Thread: Bulge buster 40SW

Ok i need to preface what i have done, also ive been reloading for a wee while now. Ive shot FTR and am well aware of case volumes and neck tension, turning etc etc, ive even marked cases in the past at the 12 o'clock position on the base of the case to ensure the round was chambered in the same place ever shot, i even weighed cases bla bla.......

the cases im shooting in the 40SW glock are of a mixed assortment of manufacturing, i also am shooting 9mm BUT these are all once fired Speer cases, this is whats giving me a control group and have a smaller variance i.e

9mm String using ADI AP70N Dillion press
1045
1070
1049
1035
1070
1051
1048

my 40SW using ADI AP70N Dillion press
879
849
742
837
737
838
857
722
852
858
737

thought ok lets negate the press powder measure and dusted off the handy dandy RCBS Charge Master Combo, set it up left it for 30 mins and then calibrated. as i was after Major PF i went with the following loads

5 5.1 5.2
933 891 error
874 930 914
865 857 943
860 927 934
895 857 917
930
(having issues lining up the above but 930 is in the middle string at 5.1)

now as i have just sat down and done the maths, first two loads have a variance of 73fps which is interesting and the last 29, yes a shorter string with the last load but still makes me wonder a couple of things

my OAL is off the top of my head is 1.140 and this was done to reduce freeborn to rifling, and i assumed that in doing so would have reduced velocity and pressure, so has my reduction in case volume by increasing the powder charge "stabilised" the detonation of the powder and in turn given a better consistent FPS?

the pain in the butt is my preferred most accurate load is 4.9 and as you can imagine isn't within a bull roar of the PF im after!

actually after sitting down and writing this i think ive negated the brass haven't i !!!!!!!

so.......as im just going baby steps, do i retest with an OAL of 1.130, Then possibly a gentle increase of crimp.........or stop being a tight prick and get a different powder? and yes Bill if your reading this I KNOW