Ruger New Model Blackhawk .357 / 9mm

When I was at Ruger the company made bunches of Police Service Six revolvers in .380 Rimmed (British Service Mk2z) for India.  This cartridge is dimensionally similar to the .38 S&W, except that the WW2-era military round used a long ogival-nosed 178-grain FMJ bullet, instead of the 146-grain LRN of the US .38 S&W.

Quite a few of those India revolvers were assembled reworking 9mm guns leftover from the French order, simply rechambering the 9mm cylinders to slightly lengthen the chamber body from the 0.754” length of the 9mm Parabellum to the 0.775 for the .38 S&W, repolishing and re-roll-marking the barrels.  The 9mm cylinders had already been faced on their outer circumferential edge to clear the 9mm moon clips, but the DA revolver extractor provided ample purchase for normal headspacing of the .38 S&W rim.  The first 10,000 India “.380 Rim” revolvers could use either 9mm Parabellum ammunition with moon clips, or .380 Mk2z (.38 S&W) without the clip.  The chambering reamers used for this cut a gradual 1-1/2 degrees Basic transition from the 0.385” mouth diameter of the .38 S&W case down to the 0.3555” diameter cylinder throats of the 9mm cylinders, to slowly squeeze down the .363” bullet.  

While it is true that this expedient conversion raised chamber pressure, the increase was within safe design limits, approximating .38 Special +P, well within continuous duty limits of the sturdy Ruger revolver.  It also resulted in higher velocity and better accuracy than obtained with dedicated .38 S&W cylinders and barrels manufactured to drawings the India Government furnished, based upon 1940 British Army practice.

The .380 Mk.2z was and is a mild load, producing only 630+/-30 fps. With jacketed ammunition “bullet in bore” (abbreviated “BIB") malfunctions were common during WW2 service.  While the India Government inspectors were initially reluctant to accept any design modification which deviated from the sacred texts of their Ordnance Department, a simple shoot-off of ten revolvers of each configuration was convincing.

All of my Ed Harris “wonder guns” ran 1000 rounds each with no malfunctions using their Kirkee Arsenal .380 Mk2z ammunition. The tighter cylinder throats and barrels produced a whopping 700 fps with smooth function and extraction.  The higher chamber pressure resulted in a “cleaner burn” and after test firings guns of dual-caliber configuration were noticably cleaner than those made to the original IOF drawings, which coincidentally ALL failed due to bullets stuck in barrels prior to any of them reaching the 500 round mark, three doing so within the first 100!    Group sizes firing .363-inch diameter 178-gr. FMJ bullets which were squeezed down like a watermelon seed through the rechambered 9mm cylinders and .354” groove diameter barrels was about 2-1/2” at 25 yards, almost exactly HALF that of the revolvers made to the India drawings, which required minimum .360 cylinder throats and .358 barrels with an allowed + tolerance of 0.0015 on each dimension.  Hmmmm.

Turn the clock up 30 years, and this curmudgeon comes across a bunch of .38 S&W Western Luballoy and Remington 146-grain lead .38 S&W rounds in a yard sale, at a price too tempting to pass up, but with nothing to shoot them in. 

Brain matter starts churning.... I took some .38 S&W rounds and dropped them into the loose 9mm cylinder for my Convertible New Model Blackhawk.  I had bought the gun used and never shot the 9mm cylinder, having been cured of the “9mm affliction” years ago and gotten rid of all pistols I once had in that caliber. Still, having a 9mm cylinder for the Blackhawk seemed an OK idea, just in case a crate of ammo ever fell from the sky off of one of those alien spaceships George Noory is always talking about on late night AM radio.....

As I correctly remembered, .38 S&W rounds stopped about 0.020” short of seating in the chambers.  I took a handful ran them through my Lee 9mm Factory Crimp Die, adjusting it all the way down until I had a distinct “bump” against the shell holder at the top of its stoke.  The resized and heavily taper crimped rounds would enter the chambers almost all the way, but had to be forced in the last wee bit.  Upon extraction you could see rubbing of the case mouth where the now tapered case mouth interferes with the sharp edge of the stop surface on the 9mm chamber.  The photo below shows a factory .38 S&W cartridge at left, and at right, one which has been recrimped and resized using the Lee 9mm Factory Crimp Die. 

I remembered my previous exercise in lapping the chamber throat entrance of my .45 ACP Blackhawk cylinder, and looked around the shop to see what I had which would break the sharp edge to provide clearance, without damaging the outer circumference portion of the stop surface, needed to headspace those 9mm rounds I would hope to find cached one day in the woods after “the end of the world as we know it."  Brownells makes ball-end revolver chamfer tools in 3/8” and 1/2” diameter, which are normally used to gently break the wire edge of a revolver forcing cone, to reduce spitting in service guns used fired with lead ammunition.  The smaller 3/8” ball cutter is intended for .22 and .32 revolvers, but was of just the right length and diameter to reach into the 9mm chambers, turn gently by hand, to break the sharp edge of the stop surface in the 9mm chambers.  Rounds rounds would then seat fully and fall out of their own weight without interference.

Upon firing accuracy of the re-profiled .38 S&W factory loads was of normal plinking quality, about 3” at 25 yards.  But the real purpose was really to get fired brass to reload.  OK, the case mouths looked a little ragged, where they had been pinched and the bullet bases forced through, but they cleaned up perfectly after trimming to 0.750.” From then on they would be sized, expanded and crimped using ordinary 9mm dies with a .38 Special shell holder.

So if you find a bunch of .38 S&W rounds and don't know what to do with them, you can turn them into “9mm rimmed.”  But just keep the loads mild, keeping to .38 S&W data, in case somebody actually tries to put one in a .38 S&W!  I'm looking to approximate the old .380-200 lead bullet service round used.  A mild recoiling, 200-grain bullet at about 630 fps with 2 grains of Bullseye should be just the ticket for fast runs at cowboy steel targets, and perhaps as a quiet Rook Rifle load!