Sunday, June 17, 2007

A great 9mm Luger defensive load, or “Remington Golden Sabre rules”

I’ve been skeptical about 9mm Luger loads with 147gr bullets, because given the limited OAL as required by a typical 9mm magazine, one must seat the rather long 147gr bullet so deeply into the case, that the volume left for powder is limited. This skepticism however changed when I recently picked up a 9mm Luger barrel for my CZ 52.

As any gunnut astute reader will know, a CZ 52 pistol is traditionally chambered for the Russian 7.62x25 Tokarev round, which is typically 1.380” long. A typical magazine limited 9mm Luger round is only 1.150” long, so allowing 9mm Luger rounds into a CZ 52 magazine opens up vistas of interesting 9mm Luger loads with heavy bullets.

I tried two bullet types,

  1. a Winchester 147gr JHP bullet and
  2. a Remington 147gr JHP Golden Sabre bullet.

To my disappointment, I couldn’t seat the Winchester bullet out as far as I had hoped because, though the CZ 52 magazine can accomodate longer rounds, the barrel is cut for traditional 9mm Luger loads and hence the furthest I could seat the bullet before it contacted the lands of the barrel was for an OAL of 1.130”.

The Remington Golden Sabre bullet however is a horse of a different color. You’ll note that Golden Sabres don’t have a uniform diameter but instead have a 0.18” wide “drive band” near the base, which is 0.356” in diameter, and then the bullet diameter abruptly steps down to 0.348”. This allows the bullet to be longer than would be the case if the diameter was uniform. But more importantly, in my case, it allows one to seat the bullet further out of the case before it makes contact with the barrel lands. I could build a cartridge with a length of 1.190”, longer than what I could do with the Winchester bullets.

I wanted a load that would achieve at least 1050fps with a less than +-10fps velocity deviation. I chose Power Pistol (because that’s what I have) and varied the powder weight from 4.2grs to 5.3grs, with a 0.2gr delta. This was done with care, as my Speer manual recommends not going beyond 5.0 grs for this loading.

Fortunately, no signs of overpressure (flattened primers, shiny case bases) were observed. The following shows the curves of powder weight vs. velocity of the two loads with y-axis error bars showing SD in velocity.

As expected, the curve of the Winchester loading, with it’s smaller powder volume, starts to reach a plateau at around 5.0 grs of powder, whereas the curve of the Remington loading, with it’s larger powder volume, is still linear up to the limit of this experiment. 5.1grs of powder seems to be a sweet spot, from a velocity deviation standpoint, for both loadings, with a velocity of 1041+-7.8fps and 1004+-8.9fps respectively.

Accuracy-wise, all rounds landed in 2-3” circle, firing offhanded, unsupported, through a Chrony from 15yds.

Since the Remington loading is still linear at 5.2grs of Power Pistol, naturally we must find the point of inflection there too. Stay tuned next week ..... [Did I already say that I love Remington Golden Sabre bullets?]

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