SpangledHatch
Member
- Joined
- Dec 3, 2019
- Messages
- 7
I went out to the range yesterday to test some attempts to replicate the Speer 135gr short barrel 38 +p round.
This is my first time chronographing, and I'm a little confused about some aspects of the results, specifically high standard deviation and extreme spread observed across all my testing, including the control groups with factory cartridges.
In short, I'm seeing SD's greater than 30, and ES's of 90 and above with all tests. Velocities are a little lower than I expected as well.
I loaded these cartridges very carefully - all brass is of the same headstamp (once fired), each charge was hand weighed, and overall length was tightly controlled.
I was about 6 feet from the front of the chrono. The only thing I can think of is maybe getting a little more distance.
Any input appreciated.
Load data used from https://www.speer-ammo.com/download...iber_357-358_dia/38_Special_P_135_GDHP_SB.pdf
My chronograph data is as follows:
This is my first time chronographing, and I'm a little confused about some aspects of the results, specifically high standard deviation and extreme spread observed across all my testing, including the control groups with factory cartridges.
In short, I'm seeing SD's greater than 30, and ES's of 90 and above with all tests. Velocities are a little lower than I expected as well.
I loaded these cartridges very carefully - all brass is of the same headstamp (once fired), each charge was hand weighed, and overall length was tightly controlled.
I was about 6 feet from the front of the chrono. The only thing I can think of is maybe getting a little more distance.
Any input appreciated.
Load data used from https://www.speer-ammo.com/download...iber_357-358_dia/38_Special_P_135_GDHP_SB.pdf
My chronograph data is as follows:
Code:
135gr Speer GDHP SB .38 S&W Special
2/3/2020 - 70F - 30% Humidity - S&W 442 1 7/8" bbl
CCI 500 Primer
Remington-Peters Nickle Brass
1.450" COL
4.8gr Unique - MV 700 fps, SD 49, ES 136
622 fps
718 fps
692 fps
758 fps
711 fps
5.0gr Unique - MV 741 fps, SD 32, ES 90
NR
752 fps
NR
784 fps
769 fps
694 fps
776 fps
722 fps
719 fps
717 fps
5.2gr Unique - MV 776 fps, SD 41, ES 142
752 fps
814 fps
759 fps
789 fps
739 fps
697 fps
765 fps
839 fps
808 fps
795 fps
Factory - MV 781 fps, SD 36, ES 118
698 fps
785 fps
NR
NR
816 fps
779 fps
785 fps
782 fps
808 fps
800 fps