[RDub01]

Hi

Shot some 180gr Speer TMJ's through a G20-SF with 3N38 powder.


Glock 20SF with factory barrel and spring
Rounds were seated to 1.26” COL
Circles are 5½” at 25 yards
Shooting was done off of a Caldwell Pistol Rest
Velocities taken with an Oehler Mod 33 chronograph. Skyscreens centered 8’ from muzzle.





Data on targets;

Average velocity
Velocity spread
Standard deviation
temperature

Case head expansion;
11.3grs is about max in this gun, maybe a bit less in warmerweather.
I had an erroneous chrono reading on the 11.3gr string thatI didn’t catch, which screwed up the average, but I recall seeing velocities inthe low 1200’s
10.4grs minimal expansion
10.7grs .4335,.4335, .4335, .4330, .4336
11.0grs .4339, .4335, .4336, .4337, .4336
11.3grs .4340,.4338, .4339, .4340, .4342
11.6grs .4339,.4346, .SMILEY, .4345, .4339

I don't know why the groups were so far left and high..