Wednesday, February 22, 2017

Work Slowdown, Part One...

So, one thing about the current crop of micro-nines is that the shorter barrel lengths are going to have an effect on the velocity of the rounds they fire. To see just how much of an effect, I took the Glock 43 and my Robar Custom G17 to Marion County Fish & Game to do a little chronograph work yesterday.

First up we'll look at Hornady's Critical Defense in its standard-pressure 115gr form. The first number on each line will be as measured from the 43, the second will be from the full-size 17:
LO: 1059  1160
HI: 1093  1183
AV: 1080  1172
ES: 33.40  23.02
SD: 11.35   7.54
Hornady claims 1140fps from a 4" test barrel, and the numbers from the 3½" G43 and 4½" G17 bracket this nicely. Hornady also claims that the Critical Defense is optimized to function at the slower velocities found from shorter-barreled CCW-type guns as opposed to full-size service pistols, but that will have to wait until Phase Two of this post, where the jello gets shot.

Meanwhile, on to Federal's 124gr HST. This stuff was zippy enough that after firing the first couple rounds, I set the gun down and checked the box flap to make sure I hadn't grabbed some +P by mistake. Nope, standard-pressure 124gr HST it was. Federal's ad copy claims 1150fps, and this seems about right:
LO: 1099  1169
HI: 1133  1208
AV: 1118  1198
ES: 33.47  38.66
SD: 10.58  11.66
Note that while both the 124gr HST and 115gr Critical Defense are nominally standard-pressure loads, and the Hornady makes no claims of "reduced recoil" or "lite" or suchlike on the box, the heavier Federal bullet is still 25-40fps faster, meaning that the Critical Defense is pretty much a "-P". While the Glock didn't seem to mind them, many guns I have tested have been shown to have problems functioning with light bullets going that slowly (*coughCanikSteyrRugerAmericancough*)

In a self defense situation, I don't know how I feel about having ammunition that's on the ragged edge of having enough ass to function the weapon provided I'm gripping it properly. Caveat emptor and test your carry stuff in your own gun thoroughly.

Last up was Winchester's 147gr "Defend" ammo, which appears to use a variant of their SXT bullet.
LO: 913.1  980.5
HI: 954.6  1037
AV: 928.8  1019
ES: 41.48  57.25
SD: 11.61  16.00
Again, pretty well bracketing Winchester's claimed 950fps test velocity.

The next phase of this is obviously to see what effect the differing velocities have on terminal performance in ballistic gelatin.

Then it was on to building the round count on the Glock 43 by having some fun hammering steel. Having fired thirty various rounds of JHP during chrono testing, I popped off another twenty rounds of the HST before switching to the two boxes of Magtech 115gr FMJ I'd brought along. This meant a round count of one hundred and fifty on the day for the microGlock.

There were no malfunctions of any type to report.

This makes 1,350 rounds fired since the gun was cleaned or lubricated with no malfunctions. 650 rounds to go.