blackhawk 9mm/357mag convertible comments on accuracy

[oldcrab]

When I saw the blackhawk convertible for 9mm/357mag, it looks like a barrel of fun at the range.
One thing I'm wondering about is how transferring back and forth between jacketed bullets of two diameters will work for accuracy. The two cylinders take away anything weird happening prior to the forcing-cone-and-barrel dimensions, but then the cone and barrel are one dimension but have to handle .355" and .357" diameter ammo.... Does it handle both accurately, with minimal or "normal" coppering, or do you see one caliber being the more accurate of the two different rounds????

 

[BULL'S-EYE]

9mm ball ammo with .355 bullets is usually only good for minute of 6" steel plate with carefully aimed firing at 25-50 yards or so in my experience, but carefully tailored handloads, with properly sized .358 cast bullets (as well as properly adjusted reloading dies) have provided some rather outstanding accuracy in my favorite 3-Screw 357 Blackhawk. In fact, this outside sourced and fitted 9mm cylinder has been in place for several years now...And has provided me with much shooting enjoyment.

 

[Wvfarrier]

My barrel slugged .356 which falls right between 9mm (.355) and 357 mag (.357) so both shoot exceptionally well. My Korth with dual cylinders is less accurate because the barrel is a true .357

I will often reload 9mm using 357 mag projectiles so they shoot more accurately

 

[GarrettJ]

I will often reload 9mm using 357 mag projectiles so they shoot more accurately

I get that one can load bullets appropriate for a .357 Magnum barrel in a 9mm case. But that somewhat defeats the purpose here.

If I'm going to load .357" or .358" bullets to shoot in a Blackhawk, I'll just load them in a .38 Spl. or .357 Mag case, and load .355"/.356" bullets in 9mm cases, so they can be used in any of my 9mm guns.

The whole appeal of the 9mm cylinder is so people can shoot the more inexpensive and available ammo.

 

[woodperson]

The 9 mm cylinder for the convertible gun has a tapered throat in front of the bullet. The throat is sized for the 9 mm bullet right in front of the chamber and expands to .357 at the front of the cylinder. You can verify this by dropping 9 mm Hornady jacketed bullets in from the front of the cylinder. So with the proper load and bullet the 9 mm bullets expand to .357 in the throat and hit the forcing cone the same size as .357 bullets. For the same reason it is difficult to simply load ,357 bullets in the 9 mm cases. The bullets will stick in the throat. My gun shoots pretty good with 9 mm. But my best groups are with .357. One reason is that I just do not try for great accuracy with the 9mm loads. I have a red dot on the gun. One thing for sure, the 9mm shoots to a different POI than the .357. Even though I have the 9mm cylinder and have used it "just because" I have no real use or love for it. I can do everything I need with the .357 cylinder. Except, of course, use 9 mm ammo. Note: All my 9mm experience is with jacketed or plated bullets. None with exposed lead bullets. I do not have another 9mm gun. So no real need for this one.

 

[oldcrab]

thanks to all replies.... great information!

 

[Rclark]

My medium frame .357/9mm flattop is plenty accurate with .357 cylinder. Can't comment on 9mm as I don't use that cylinder. That said, one man's accurate shooting is another's barn door . So you'll have to see for yourself .

 

[s4s4u]

Be prepared to re-zero each time you swap cylinders. That kinda defeated the purpose of the exercise for me. An inch or two, banging steel, I could live with. But missing a 10" gong @ 25 yards was too much deviation and therefore the secondary cylinder stayed in the bag.

 

[Springer2]

We have had a 357/9mm for years and it works fine. The 9mm is more challenging to get accuracy than shooting 38s. I looked at my old photos and these were the only ones I found now. They were only shot from 15 yards but both the 357 and 9mm do not need sight adjustments with these loads. FYI: the 9mm bullet is sized at 0.356".

 

[mpmax]

Last Monday I was hitting "Minute of Bowling Ball" at 50yds with both cylinders off hand with BFR rear sight (modified) for fixed front sight. Also has the tasty super Blackhawk hammer.