So this is the second set of rounds that I've worked up using 180 JHP's, with AA#7.
This post is a continuation of this post: http://thefiringline.com/forums/showthread.php?t=561160
Charge weights: 11.7gn; 11.8gn; 11.9gn; & 12.0gn (Speer #14 and Hornady 9th both max at 12.0gn). All charges hand weighed.
Bullet: Everglades 180gn JHP: OAL 1.255" +.000 / -.005
Primer: CCI 300
Brass: Starline
Guns: Glock 29sf (3.7" bbl), Lone Wolf barrel; & Glock 20sf (4.6" bbl), Lone Wolf barrel; aftermarket Titanium recoil spring.
Purpose: High recoil range practice; emulating full power defense rounds.
10 round strings from each gun.
Results:
11.7gn
G29 - 1193 fps avg; 29.73 SD
G20 - 1226 fps avg; 16.40 SD +33 fps over G29
11.8gn
G29 - 1191 fps avg; 27.16 SD
G20 - 1241 fps avg; 32.28 SD +50 fps over G29
11.9gn
G29 - 1215 fps avg; 42.35 SD
G20 - 1243 fps avg; 30.54 SD +28 fps over G29
12.0gn
G29 - 1222 fps avg; 38.00 SD
G20 - 1268 fps avg; 24.31 SD +46 fps over G29
Comments: Moving to Starline-only brass didn't help with consistency - as I suspected. Standard Deviations were not pleasing. However, I also tested a more mild (unrelated - different bullet, different powder) round today, and they ran in the mid-30's too. So I'm not going to blame the powder or bullet. I don't have a lot of previous chrono data for 10mm to use for reference. Of the few I do have, all were more mild loadings. But their SD's were running in the high-teens and twenties. So maybe with hot rounds, SD's in the 30's n 40's may be more or less normal.
All that said, I'll probably choose 11.6gn (tested the previous trip) for the "set" round - only because it's a nice comfortable 0.4gns below the publish max, giving lots of headroom. I'm in a "whatever" mood regarding this right now. They all shot pretty much the same, so it really matters not which one I settle on. I'll load up a bunch of 11.6's to shoot without the chronograph in my way, and I'll see how I feel about them.
A similar workup using Power Pistol is probably on the horizon.
This post is a continuation of this post: http://thefiringline.com/forums/showthread.php?t=561160
Charge weights: 11.7gn; 11.8gn; 11.9gn; & 12.0gn (Speer #14 and Hornady 9th both max at 12.0gn). All charges hand weighed.
Bullet: Everglades 180gn JHP: OAL 1.255" +.000 / -.005
Primer: CCI 300
Brass: Starline
Guns: Glock 29sf (3.7" bbl), Lone Wolf barrel; & Glock 20sf (4.6" bbl), Lone Wolf barrel; aftermarket Titanium recoil spring.
Purpose: High recoil range practice; emulating full power defense rounds.
10 round strings from each gun.
Results:
11.7gn
G29 - 1193 fps avg; 29.73 SD
G20 - 1226 fps avg; 16.40 SD +33 fps over G29
11.8gn
G29 - 1191 fps avg; 27.16 SD
G20 - 1241 fps avg; 32.28 SD +50 fps over G29
11.9gn
G29 - 1215 fps avg; 42.35 SD
G20 - 1243 fps avg; 30.54 SD +28 fps over G29
12.0gn
G29 - 1222 fps avg; 38.00 SD
G20 - 1268 fps avg; 24.31 SD +46 fps over G29
Comments: Moving to Starline-only brass didn't help with consistency - as I suspected. Standard Deviations were not pleasing. However, I also tested a more mild (unrelated - different bullet, different powder) round today, and they ran in the mid-30's too. So I'm not going to blame the powder or bullet. I don't have a lot of previous chrono data for 10mm to use for reference. Of the few I do have, all were more mild loadings. But their SD's were running in the high-teens and twenties. So maybe with hot rounds, SD's in the 30's n 40's may be more or less normal.
All that said, I'll probably choose 11.6gn (tested the previous trip) for the "set" round - only because it's a nice comfortable 0.4gns below the publish max, giving lots of headroom. I'm in a "whatever" mood regarding this right now. They all shot pretty much the same, so it really matters not which one I settle on. I'll load up a bunch of 11.6's to shoot without the chronograph in my way, and I'll see how I feel about them.
A similar workup using Power Pistol is probably on the horizon.