Now that I've been home and have had time to think about the testing and your responses . I can update what's going on with more specificity .
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Originally Posted by Me
The velocities were above 1100fps and would jump up from there
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First let me add this . I first shot rifle at the 300yd range and ran a TMK ladder test using the chrono and it worked very well . When I went to the pistol range the chrono was only getting error readings so I started the load development with out it . About half way through I tried taking off the baffle things and that worked and I was able to use the chrono for the rest of the test . This is why I said the velocities were 1100 and above , I never tested the lower charges . I very well could have been getting those erratic velocities through out the load spectrum .
Second and "maybe" not as important is that I used mixed brass and I could clearly tell some case walls were thicker then others while crimping resulting in a heavier crimp with some cases . I would say most had a light crimp and some ( Random 10% ) had a light medium to medium crimp . I say "MAY" not have contributed because the 9mm load I ran over the chrono to test it's consistency used mixed brass as well and it was consistent with a very low ES/SD .
Seating depth
Yes I seated these bullets pretty deep . My COAL was 1.090 . Gold dot suggest 1.125 for there 115gr HP so I was .035-ish shorter . My reasoning for seating as deep as I did was that when comparing the 115gr bullets to the 147gr bullet . The 115gr bullet had much less barring surface . I concluded the bullet needed as much of that area seated in the case to insure bullet hold .
Here are a few numbers
Barring surfaces ----- 147gr .335 / 115gr .235 these are approximate
If I were to seat the bullet to just touch the lands in my XD-9 the COAL would be 1.155 leaving .170 of bullet hold in the case , is that enough ??
FWIW with my S&W shield the bullet does not even hit the lands at a COAL of 1.170
All that said I do have CFE pistol I can try . Maybe it will ignite better then HS-6 and if I use a COAL of 1.125-ish I may get a more consistent powder burn ????
I really don't want to put to much effort into this 115gr bullet if it results in a firearm specific load . Meaning it's very unlikely I try running the bullet real long to touch and or head space off the lands of any one pistol . If I can't get a safe consistent 1150 to 1200 fps load with it I'll just use a different powder and make a plinking load .
Side note , I'm training to be RSO and once I am I can go to the range after hours and shoot alone . When this option is available to me . I'll do some ballistics test and see at what velocities these bullets really expand .