Just had my first try at chronographing some ammunition. New CED Millennium and enough sun to make it work provided ten string results for some factory ammo and one reload.
My reload was 45 ACP Shot from a Glock 21
Load: 6.1 gr. Universal
Bullet: 230 gr. West Coast Plated RN
Primer: CCI Large Pistol
OAL: 1.240"
I started with Hornady data for a 230 gr. FMJ-RN / COL: 1.230" / Winchester WLP primers. They show max load for Universal out of a 5" Barrel was 6.4 gr. Resulting velocity was 900 fps.
I used a plated bullet, COL: 1.240 and CCI primers. All parameters that differ from Hornady.
I dropped the charge to 6.1 gr. and loaded on a RCBS Pro 2000.
My chrono results from a ten shot string was as follows:
Ave. Velocity: 917.8
S.D.: 39.2
High: 967.4
Low: 827.0
E.S: 140.4
I didn't see any signs of stress on the brass.
How do I interpret these data?
Does the velocity indicate that I'm in the pressure danger zone?
Is the large standard deviation an indication of poor metering, or is it rapidly increasing pressure with slight changes at, near, or above max pressure? In other words, getting close to overpressure.
I would like to use this as a learning experience. What is a good S.D. for progressive ammo? Is my choice of powder questionable due to metering problems, or is my choice of 6.1 gr. a questionable high starting point?
Thanks,
Gary
My reload was 45 ACP Shot from a Glock 21
Load: 6.1 gr. Universal
Bullet: 230 gr. West Coast Plated RN
Primer: CCI Large Pistol
OAL: 1.240"
I started with Hornady data for a 230 gr. FMJ-RN / COL: 1.230" / Winchester WLP primers. They show max load for Universal out of a 5" Barrel was 6.4 gr. Resulting velocity was 900 fps.
I used a plated bullet, COL: 1.240 and CCI primers. All parameters that differ from Hornady.
I dropped the charge to 6.1 gr. and loaded on a RCBS Pro 2000.
My chrono results from a ten shot string was as follows:
Ave. Velocity: 917.8
S.D.: 39.2
High: 967.4
Low: 827.0
E.S: 140.4
I didn't see any signs of stress on the brass.
How do I interpret these data?
Does the velocity indicate that I'm in the pressure danger zone?
Is the large standard deviation an indication of poor metering, or is it rapidly increasing pressure with slight changes at, near, or above max pressure? In other words, getting close to overpressure.
I would like to use this as a learning experience. What is a good S.D. for progressive ammo? Is my choice of powder questionable due to metering problems, or is my choice of 6.1 gr. a questionable high starting point?
Thanks,
Gary