9mm Blackhawk cylinder fit

[eveled]

I just got a 9mm cylinder for my Blackhawk. I was able to stone the post down and get the correct overall length. My cylinder to barrel gap is .003, which seems a little small, but I can live with that. A little tight is better than too loose.

My issue is I think 3 of my chambers aren't deep enough. Creating not enough head space and it causes the cylinder to bind.

Head space for 3 chambers is .006 the other 3 are .007. Measured using the same round in the chamber. All the chambers are very clean. I checked the .357 headspace is .008

What should the head space be for the 9mm? What chamber reamer would I need?

 

[eveled]

The shell catches on this lip, I'm surprised it's not tapered. Should I taper it?

 

[eveled]

These three seem fine

These are not especially the one in the middle

I feel like they should all be a little deeper.

 

[rugerguy]

rotate each shell to the next cylinder and "look/see" if the protrusion is the same, so as to determine its the chamber itself and NOT any particular shell,,,then yes may have to run a finish reamer into the shallow chambers...easy for us to say when we would just put the finish reamer into the chambers as we KNOW the reamer is "proper" length ( depth) nothing wrong with a ;shorter" space out front, unless you use soft ,lead bullets,then you may get "fouling" and close up the gap even more....what is the spacing with the other cylinder, that the gun came with???
....and yes , you can polish ( bevel) that small "ledge", so as to not cause the rim to "catch".........take your time, neatness counts, and yes can touch it up with a bit of cold blue........

 

[eveled]

I did exactly as you described same shell rotated through each chamber, then with a different shell numerous times. Even different brands. That one chamber always was the problem. Protruding too far and catching or just missing that ledge.

With the .357 cylinder the b/c gap is .006 the headspace .008,

I will bevel the ledge and find a finish reamer. Then ream them all to the right depth.

Thanks for your time, @rugerguy

 

[eveled]

Easy job when you have the correct tool.

I sourced a 9mm cylinder reamer, I guess it's different than a chamber reamer? Turned it with a wrench about 30 times in the real bad one, then checked the others real close and 5 of the others needed between 5 and 15 turns, and now they are all the same as the lowest original. (The one on the right side in the first picture above.)

I neatly turned that ledge into a ramp and touched up with cold blue.

Thanks again @rugerguy

This is my first handgun from 30+ years ago. It felt good to give it some attention.