9mm velocities too high
Quote from Reloader on March 9, 2014, 4:48 amI'm new to reloading, so I've been very careful to ensure the powder charge and OAL are very close to specs. Using the 550B, Power Pistol at 5.3 grains, Sierra 8125 bullets, OAL at 1.075 or slightly greater. Went to the range today and did some chronographing. Pretty consistent at or near 1450 fps with a standard deviation of about 3.8 fps (Chrony about 6 yards away shooting through a 92FS). Lyman manual says I should be getting about 979 and 1107 fps for this recipe. So, while my loads seem very consistent, something is not quite right.
Anyone have any thoughts as to the cause? Is the Chrony possibly too close? Shooters next to me on the range were chrony-ing high powered rifle rounds with the chrony at the same distance.
Thanks!
I'm new to reloading, so I've been very careful to ensure the powder charge and OAL are very close to specs. Using the 550B, Power Pistol at 5.3 grains, Sierra 8125 bullets, OAL at 1.075 or slightly greater. Went to the range today and did some chronographing. Pretty consistent at or near 1450 fps with a standard deviation of about 3.8 fps (Chrony about 6 yards away shooting through a 92FS). Lyman manual says I should be getting about 979 and 1107 fps for this recipe. So, while my loads seem very consistent, something is not quite right.
Anyone have any thoughts as to the cause? Is the Chrony possibly too close? Shooters next to me on the range were chrony-ing high powered rifle rounds with the chrony at the same distance.
Thanks!
Quote from Reloader on March 10, 2014, 5:24 pmI would suggest two things. First, verify the powder charge weight, then verify your bullet weight, using your scale. Second, the minimum cartridge overall length suggested by Alliant powder is 1.120", longer than your current OAL. I suspect if the weights are correct, then the short OAL is the casue of the higher velocity (and resultant pressure increases)
I would suggest two things. First, verify the powder charge weight, then verify your bullet weight, using your scale. Second, the minimum cartridge overall length suggested by Alliant powder is 1.120", longer than your current OAL. I suspect if the weights are correct, then the short OAL is the casue of the higher velocity (and resultant pressure increases)
Quote from Reloader on March 11, 2014, 2:51 amInteresting. I looked up the Alliant guide and what you say is correct (max 1.12 OAL). This is in conflict with the data in the Lyman's manual (49th edition, Page 341, 9mm Luger with a Sierra 8125 bullet) which shows an OAL of 1.075 for the 8125 bullet. Incidentally, they have OALs less than 1.12 for all the 9mm Luger loads in the book.
I'll have to continue to research.
Thanks for a response!
Interesting. I looked up the Alliant guide and what you say is correct (max 1.12 OAL). This is in conflict with the data in the Lyman's manual (49th edition, Page 341, 9mm Luger with a Sierra 8125 bullet) which shows an OAL of 1.075 for the 8125 bullet. Incidentally, they have OALs less than 1.12 for all the 9mm Luger loads in the book.
I'll have to continue to research.
Thanks for a response!
Quote from Reloader on March 26, 2014, 6:52 pmI have had the same problem. It seems the primers have alot to do with this. Did you check the case capacity visually to see if it is a compressed charge. It's the only thing I can think of that would cause these velocities. Using magnum primers will cause just this type of thing. I mistakenly used some (Mag, small pistol primers) instead of the regular, and that's what happened.
I have had the same problem. It seems the primers have alot to do with this. Did you check the case capacity visually to see if it is a compressed charge. It's the only thing I can think of that would cause these velocities. Using magnum primers will cause just this type of thing. I mistakenly used some (Mag, small pistol primers) instead of the regular, and that's what happened.