Educate me on Ruger 357/9mm convertibles

[Outpost75]

Rare gun to look for is an early Ruger Police Service Six in .380 Rimmed, which was rechambered using one of the 9mm cylinders from the French order circa 1980-83. The outer circumference of the cylinder is turned and faced back to clear the Ruger design half-moon clips, while the 9mm cylinders were rechambered to .380 Mk2 with a gradual transition to squeeze the .360" bullets into the .356 cylinder throats. That way you can shoot 9mm with the clips, or .38 S&W without clips.

Dave Manson ground for me a .38 S&W "Rook Rifle" reamer which John Taylor used to make a .38 S&W rook rifle for me. Almost silent with 190- grain lead bullet and 2 grains of Bullseye from 20" barrel, like large caliber air rifle, no can needed. I also used this reamer to clean up my S&W 940 cylinder so that revolver can use .38 S&W without clips, or 9mm with the star clips.

If you also have .38 S&W revolvers, the mod makes your 9mm revolvers more useful. In the Ruger 9mm revolvers 3.5 grains of Bullseye with the Speer .357", 135-grain Gold Dot JHP gives 880 fps in a 1-7/8" barrel and 950 fps from a 4" S&W 547 or Ruger Service Six.

[jonp]

No minus I can think of although neither my 9mm/357 or my 45acp/lc are first choice semi auto guns. I use them to shoot mistakes up in both the other calibers. I highly recommend them for that use and just because they are cool.

Remember, if you lose magazine you now have 1 shot guns. The Blackhawks will never be like that, they will just work until...the end of time?

[Bubba w/a 45/70]

A few months ago Handloader mag #313 (april 2018) did a write up on the 357/9mm swap cyl . finding a load that shot to point of aim for all could be a problem , however the article has it somewhat figured out for you with velocities and loads and the drop on each load . using a fixed sight Ruger Vaquero and using a Caldwell HAMMR mechanical handgun rest with the same aiming point @ 25 yards ,loads were from 14.0 " low to 1.5 " low for the 9,38&357 using the chart you can come up with a load that could be pretty close to the same POI

Bobthenailer, my problem is that my chosen load for 357 is a 180gr WFN and the 9mm is closer to the 125gr area.

Looks like there isn't a happy medium for me.

[DougGuy]

My Ruger Flattop is accurate with 9mm FMJ. I haven't shot lead 9mm through it yet.

My .357 cylinder has .358" throats and shoots great with lead. The 9mm is @ .355". Has anybody opened a 9mm cylinder up to .358", and was it still accurate wth jacketed bullets?

It will be much more accurate with j words than what your .355" throats will let it be. The 9mm is a high pressure cartridge, 35,000psi operating pressure, a j word has a soft lead core swaged into a thin gilding metal jacket. When you fire the gun, pressure will obturate the rather soft j word and it will fill the cylinder throats, exiting the front of the cylinder at throat diameter, .3585" or thereabouts, thus presenting a larger boolit to the forcing cone which will give a better seal than presenting one already .002" smaller than groove diameter. It's a win win situation.

[Bubba w/a 45/70]

So getting one of the conversions, checking the 9mm cylinder, and correcting the throats on that cylinder is pretty much what sounds like the deal will be with a new one. Or am I off on my assessment?

That is if there is something that needs to be corrected for diameter, that is.

[Sam Casey]

One of my favorite .38 target loads uses a 9mm bullet with good accuracy.

[DougGuy]

So getting one of the conversions, checking the 9mm cylinder, and correcting the throats on that cylinder is pretty much what sounds like the deal will be with a new one. Or am I off on my assessment?

That is if there is something that needs to be corrected for diameter, that is.

You are pretty close, most folks that have the convertibles get both cylinders sized to .3585" and size both 9mm and 357 boolits to .358" universally. Plus if there is any inconsistencies in the throats on the 357 cylinder, they will all be honed to the same diameter within .0002" or so on both cylinders.

[bobthenailer]

Bobthenailer, my problem is that my chosen load for 357 is a 180gr WFN and the 9mm is closer to the 125gr area.

Looks like there isn't a happy medium for me.

In handloader they only used 115 &147 gr bullets for the 9mm, 110,125&158 in 38 special and 125 &158 in 357
. it looks like 125 gr or 147/158 would have the best chance to shoot close ! FME a 180 gr will shoot higher than a 158 @25 yards.
115gr 9m luger@1,201 -12.0@25 yards
125gr 38 special @837--10.0 @25 yards
125gr 357 mag @1450 fps -11.0 @25 yards
so thers is 3 loads that will have only a 2" poi change @ 25 yards

[MT Gianni]

Found the link.
http://www.castpics.net/subsite2/ByF...0Blackhawk.pdf