I am planning to have a 66 converted to shoot 9mm in moon clips.

Two gunsmiths I have found do this:
Pinnacle High Performance
and
TK Custom

Have any of you had a 9mm conversion by either of these shops? If so, I would like to here how it worked out and what you liked and what you didn't like about how the conversion worked out.

Several of my revolvers have had work done by Mark at Pinnicle

Here is a 627 with it's original, unaltered, 357 Magnum, unfluted, stainless cylinder and a second black fluted cylinder chambered for 9x23 WinchesterBecause rimless cartridges fired in revolvers headspace on the moon clip instead of the case mouth like they do in auto loaders, this revolver can chamber and fire 9x23 Winchester, 38 Super, 38 ACP, 356TSW, 9x21, 9MM Luger, 380 ACP and others that do not come to mind at the moment.

What I would suggest you do is to find another Model 66 cylinder and have that fitted to your gun and have it machined for 9 MM. TK Custom did that for me. You keep the integrity of your Model 66, yet have the versatility of the 9 MM extra cylinder. But if you just want your existing cylinder machined for 9 MM, TK Custom would be the way to go. Their work is excellent and the turn around time is very fast.

Have either of you tried to run any of the cheap steel case 9mm ammo in your conversions? I have a Ruger LCR in 9mm. It shoots and ejects fine with all brass cased 9mm, but steel cases ammo sticks and is very hard to eject.

TK's site says you can still run .38 spl and .357 mag after conversion. Pinnacle says not to run .38/,357 in their conversions because it will stick. Pinnacle's site also talks about having designed their own reamer rather than using a regular 9mm auto pistol reamer to improve function and extraction.

I would use the converted revolver strictly with 9mm ammo, so I don't care about ability to shoot .38/.357.

Have the special Pinnacle chambers shown to function any better than the chamber design TK uses?

I don't see moon clips offered on Pinnacles site. Does the Pinnacle conversion us TK moon clips?

What's factory 9mm (0.355") accuracy like from a S&W 0.357" barrel?

__________________
~ S&W aficionado in training ~

I had mine done bu Pinnacle and couldn't be happier with it. I had a J frame done but I doubt the difference would be much to speak of on a K frame. I've fired 9mm, .38 Super, .380, .38 and .357 through mine with zero issue. .357's will stick if using a high pressure round but I was still able to extract without any tools. My J frame is a 640 Pro so it already came with clips for .38/.357 that are provided to S&W by TK Custom. Instead of buying 9mm clips from TK as they are pretty spendy, I ordered some clips for the Smith 940 which was a 9mm J frame. Worked like a charm and I think they were like a buck apiece. Big win!

In the end, I'm happy with my J frame conversion and would do it again. I did use a second cylinder for the conversion to keep my gun original.

How do you get .380 to work? Their necks are too small for the TK 9mm clips I have.

Absolutly fine

Remember that .355" and .357" are the GROOVE diameter, not the LAND diameter. The land diameter on a .357" barrel is typically .346". That provides .011" of rifling to engage the projectile. So if you use a .355" projectiles you only have .009" of rifling in play. .009" of rifling engagement is more than sufficient to get a projectile spinning.

It is the spin that barrels put on a projectile that causes them to be accurate.

I don't use TK products.

The extractor groves on 380 ACP hold on just fine in all of my moon clips. It doesn't matter if they are my J-frames or my N-frames.

rbmorse- I'm not using the TK clips, just the Smith J frame clips but you are right, they don't lock in. I'd only shoot .380's in a pinch, and the only way I get it to work is by sliding the rounds into the clips which just hold them enough to headspace. I did it just to make sure it fired them reliably.

I've had TK do three guns for me..3" 66-2, 3" 60-10 and a 649.

Because they are kind of rare I bought extra cylinders for the 66 and 60...got lucky and both dropped right in with no fitting. The 649 just had the original cylinder done.

All three guns shoot .38 Super and 9mm extremely well. TK advises not to shoot 9x23 in their conversions as the 55K psi factory loads are significantly higher than the 35K working pressure for .38 Super...

I love colt_saa's 627 9x23 and if I ever come across one at the right price would send it Pinnacle to be converted just like that one...

Bob

I found a cylinder converted to 9mm by TK Custom for a 686. I fitted it to my 686 SSR so I still have the original cylinder to shoot 357\38 special. I only shoot my reloads in it that I worked up to work with the conversion. I had to do a lot of experimenting to get a load that would work but I am happy that I did it. I need to try some factory ammo just to see if it likes it.

Sent from my SAMSUNG-SM-G870A using Tapatalk

TK Custom did a 9mm conversion on a titanium .38/.357 cylinder I have in my 637-2. I was very pleased with their service and promptness.

I had my 627 pro fitted with an extra cylinder by Mark at Pinnacle to fire 9mm and all the others that Colt SAA mentioned.

Am completely satisfied with work and customer service.

I found accuracy to be on par w/ my 158 gr 38 spl with both 124 & 147 gr 9mm.

__________________
Guns + Dogs= Bliss

This is an older post but IIRC S&W now offers an N frame chambered in 9mm as the Model 929 as well as two L frame 9mm revolvers as the Model 986

S&W has been offering those N and L frame 9MM revolvers since 2013.
We got to get you looking at the newer stuff more often

BTW, your PM box is full