Anyone know for sure if they'll fit well enough to work smoothly?

Cordially,

Jim Stewart

No Sir, you will need to get the DS ones, there is enough dimensional differences to make them NOT compatable.

Thank you, Mr. Lee.

I'm not where I can access the things to try them for myself.

Better order a couple of the right one's before returning home.

Cordially,

Jim Stewart

The ones you want are the DSA model Sir.

I've shot several concealed carry matches with my Detective Special using speedloaders from my model 66 and never had a problem. My DS is one of the newer models made in the 90's, I don't know if that makes a difference or not.