Hi,
Will increasing the OAL produce lower velocities?
I tested some Pecision Bullets 125gr 9mm RN coated bullets. I'm using CCI primers, and CFE Pistol powder. The Hodgdon site indicated that for LCN 125gr, I should start with 4.4 and max of 5.0. They had a OAL of 1.125". They said velocity should be 1041 for for start and 1156 for max.
Previously, I had done Berry's plated 115 gr RN, and was using 1.13-1.134" OAL, which gauge and feed fine in my two 9mms. So, when I made the 125gr, I set up for a similar COL, and was seeing 1.132-1.136".
I did sample rounds and chrono'ed sets of 10 at the loads I made up (4.2, 4.4, 4.6, 4.8). I'm seeing that, at 4.8gr, my velocity is 1040 fps on the 4" Walther PPQ, with a SD 6.97 and spread of 24.55. All the lower loads were with higher SD (20-30) and spread (66-85).
I didn't get as good of accuracy with the shots as expected (although my contacts were bothering me today, so I was having a hard time getting a clear front sight in an indoor range).
My 115gr Berrys give 1139 fps at the chosen load.
So, I'm trying to understand why I'm getting lower velocity and to decide on load. I could do 5.0 and possibly 5.1 and/or 5.2, to see if I get an improvement in accuracy on the target.
Thoughts? Suggestions?
Will increasing the OAL produce lower velocities?
I tested some Pecision Bullets 125gr 9mm RN coated bullets. I'm using CCI primers, and CFE Pistol powder. The Hodgdon site indicated that for LCN 125gr, I should start with 4.4 and max of 5.0. They had a OAL of 1.125". They said velocity should be 1041 for for start and 1156 for max.
Previously, I had done Berry's plated 115 gr RN, and was using 1.13-1.134" OAL, which gauge and feed fine in my two 9mms. So, when I made the 125gr, I set up for a similar COL, and was seeing 1.132-1.136".
I did sample rounds and chrono'ed sets of 10 at the loads I made up (4.2, 4.4, 4.6, 4.8). I'm seeing that, at 4.8gr, my velocity is 1040 fps on the 4" Walther PPQ, with a SD 6.97 and spread of 24.55. All the lower loads were with higher SD (20-30) and spread (66-85).
I didn't get as good of accuracy with the shots as expected (although my contacts were bothering me today, so I was having a hard time getting a clear front sight in an indoor range).
My 115gr Berrys give 1139 fps at the chosen load.
So, I'm trying to understand why I'm getting lower velocity and to decide on load. I could do 5.0 and possibly 5.1 and/or 5.2, to see if I get an improvement in accuracy on the target.
Thoughts? Suggestions?