Flat top .357 Blackhawk convertable

[red caddy]

Hi all, just a few questions about the 9mm side of my Blackhawk convertible..

A while back I picked up a 9mm cylinder that dropped in and timed perfectly in my short barrel .357 3 screw Blackhawk. The .357 cylinder is very accurate (well under 2 inches @ 50 yards) however the 9mm is a whole different animal, Looks more like a shotgun pattern.

It occurs to me that the 9mm bullet is .355 /.356" bouncing down a .357 bore. What tricks don't I know to make the 9mm more accurate? I'm a long time re/hand loader. Thinking about loading a 148 Gr. hollow base wad cutter in a 9mm case for target use and plinkin'

My .45 LC/.45 ACP convertible (also not born a convertible) is accurate with both cylinders using .451" and .452" bullets, Would like to get that kind of shooting out of the .357/9mm convertible, is it possible?

Thanks in advance,

Paul in Floriduh

 

[GooseGestapo]

What ammo?

Until the mid-late '90's, the 9's had a reputation (well earned) for being inaccurate. Spec's on guns and ammo are all over the place.

A quality load (not cheap) should shoot very good from a BlackHawk barrel. They're known for running tight. (Not discussing thread coke...)

Look closely at your cylinder. I think you'll find it's the issue, not the barrel.

I suggest slugging the cylinder, and trying different loads. Particularly, some quality cast bullet ammo. Likely a .356" bullet will shoot better. Many factory FMJ 9mm have .354" bullets.
Try loading.357" jacketed 125gr bullets as well. FWIW, My S&W 9's Performance Ctr Autos prefer .357" bullets.
Rugerowners.com forum will get you more/better answers.

 

[mcb]

Try heavier bullets. More bearing area in contact with the barrel can help with the minor undersized 9mm bullet. My Blackhawk convertable shoots the heavier 9mm noticeably more accurate.

 

[JD Pinardi]

I had one of these convertables, same thing the 357 shot great the 9 mm not so much, so I got rid of it.
JD

 

[tranders]

The cylinder throats were all over the place on my Blackhawk Convertible 357/9mm. After having throats uniformed, accuracy did improve,but I still wasn't happy so I sold it. I hope you have better luck than I did.

 

[red caddy]

Thanks for the reply's all. I have uniformed the cylinder small end, very little differences.(as I said, timing and lockup were near perfect, Ruger does a very good job with interchangeability) I will try the 148 Gr. hollow base WC. My convertibles are more of a range toy than for any real purpose, I just like to get the best performance I can. On my way to Rugerowners.com. thanks again, Paul

 

[PapaG]

You are not limited by length or diameter. Load some 150 grain .357 semiwadcutters and surprise yourself. I used to shoot the RCBS 38-150KT out of a P85 and it was almost match accurate.