9mm w/6.0 gr of Longshot

[Geeman]

I was a bit surprised to see Longshot as one of the higher velocity on Hogden reloading data.  I thought that the powder would tend to be a bit slow to use in a shorter barrel pistol.  Since I recently acquired a CZ Scorpion with a 7.75" Barrel, I thought it might take advantage of slower burning powder.

Results from a LabRadar unit.

CZ Scorpion w/7.75" Barrel - 6.0g Longshot pushing 115g Xtreme plated Hollow Point.
10 Shots

Average: 1350
High: 1372
Low: 1319
Extreme Spread: 53
Std Deviation: 16.2

I also ran a clip full through a short Barrel.

CZ 2075 RAMI w/ 3" Barrel
7 shots

Average: 1103
High: 1116
Low: 1091
Extreme Spread: 25
Std Deviation: 9.8

Plenty of flash from the short barrel.

I didn't see any signs of high pressure and may push a bit more to see where it ends up.  Plenty of room in the case.

Greg

[The_Shadow]

Yes I saw the Hodgdon book load showing 6.0 grains of LS under the 115 gr, your results are very close to the book data which is based on the 4" barrel.  Thanks for the report.   

[Geeman]

More data for the Scorpion 7.75" barrel.

These loads are over Hogden (except the 6.0g), so be careful and work up. 5 shot strings.

Longshot 6.0g

Stats - Average   1355.38   fps
Stats - Highest   1367.84   fps
Stats - Lowest   1346.27   fps
Stats - Spread   21.57   fps
Stats - Std. Dev   11.02   fps

Longshot 6.1g

Stats - Average   1372.11   fps
Stats - Highest   1401.48   fps
Stats - Lowest   1354.07   fps
Stats - Spread   47.41   fps
Stats - Std. Dev   17.64   fps

Longshot 6.2g

Stats - Average   1388.76   fps
Stats - Highest   1406.14   fps
Stats - Lowest   1372.77   fps
Stats - Spread   33.37   fps
Stats - Std. Dev   14.36   fps

Longshot 6.3g

Stats - Average   1384.3   fps
Stats - Highest   1398.4   fps
Stats - Lowest   1371.01   fps
Stats - Spread   27.39   fps
Stats - Std. Dev   11.16   fps

The CZ Scorpion showed no ill effects from these loads.  I might try 6.4g because the loads were getting smaller deviations as the loads increased from 6.1 grains.  The last load was shooting about as good as my old eyes with iron sights can manage.

Greg

[Geeman]

I was wanting to understand the decrease in velocity with an increase in powder charge a little better, so I ran some new loads and shot 10 shots in the individual series.  There is a plateau!

6.0 Longshot
Shot ID   V0
1   1297
2   1347
3   1367
4   1348
5   1345
6   1342
7   1335
8   1361
9   1372
10   1348

Stats - Average   1346.24   fps
Stats - Highest   1372.09   fps
Stats - Lowest   1297.15   fps
Stats - Spread   74.94   fps
Stats - Std. Dev   20.74   fps

Longshot 6.1g
Shot ID   V0
1   1356
2   1367
3   1401
4   1350
5   1380
6   1374
7   1345
8   1381
9   1363
10   1353

Stats - Average   1366.9   fps
Stats - Highest   1400.71   fps
Stats - Lowest   1345   fps
Stats - Spread   55.71   fps
Stats - Std. Dev   17.19   fps

Longshot 6.2g
Shot ID   V0
1   1366
2   1421
3   1400
4   1376
5   1372
6   1370
7   1370
8   1357
9   1368
10   1345

Stats - Average   1374.58   fps
Stats - Highest   1421.26   fps
Stats - Lowest   1345.12   fps
Stats - Ext. Spread   76.15   fps
Stats - Std. Dev   21.57   fps

Longshot 6.3g (last shot wasn't recorded because I wanted to see if Labradar would record a double tap.  It didn't
Shot ID   V0
1   1361
2   1384
3   1416
4   1389
5   1386
6   1394
7   1366
8   1365
9   1358

Stats - Average   1380.16   fps
Stats - Highest   1416.14   fps
Stats - Lowest   1358.47   fps
Stats - Spread   57.68   fps
Stats - Std. Dev   18.95   fps

Longshot 6.4g
Shot ID   V0
1   1356
2   1385
3   1407
4   1400
5   1378
6   1385
7   1373
8   1373
9   1357
10   1388

Stats - Average   1380.2   fps
Stats - Highest   1406.68   fps
Stats - Lowest   1356.25   fps
Stats - Spread   50.43   fps
Stats - Std. Dev   16.29   fps

The plateau went up a tenth of a grain, but still only 6 fps total over .2g charge increase.  I guess I'm a gun powder geek

Greg

[The_Shadow]

Greg these were also shot from the CZ Scorpion with a 7.75" Barrel?

[Geeman]

Yes.