The COLT ejector rod makes a nice replacement for the Ruger ejector round button or crescent:
It's a no brainer although you can by four Ruger crescent rods for one Colt.
And here's my method to get the Ruger's crescent button or Colt button to nest up tight under the barrel when at rest, instead of dangling like the Ruger crescent button. Because the Ruger housing slot is straight and not curved like Colt's, I corrected the way the crescent button, Ruger or Colt didn't tuck up tight against the barrel when at rest. It also works for the Ruger crescent button and old round button which also kind of dangles. It may not bother some owners but it's simple to do if it does.
I grind and polish a 'cam' curve in the end of the rod/button as shown below (Colts thread together, Rugers are riveted and may need slight re-peening). The curve must 'nest' or align with the curve of the housing attachment screw when the button is up tight against the barrel in a Ruger straight slot housing. The curved surface of the end of the rod contacts the screw under tension of the return spring and it will "nest" on the screw by "camming" or turning the rod and button tight up against the barrel. Works for the Colt 'bullseye' round ejector button as well.
I also file just a small notch in the barrel side of the housing slot to allow the ER button to fold inward towards the barrel, so the button pops away from the barrel about 1/32" when in use and doesn't rub on the barrel.
On my Super Single Sixes (.22 and .32) I use a Colt 22 Peacemaker button:
A Blue Colt rod and head assembly (they thread together, 6x40, not riveted/peened like a Ruger) is #160-205-003AD, $32.84 at Brownells.
But Colt does not make theirs in stainless. However Brownells also sells a Colt style by MK Technologies, and they do offer it in stainless, Brownells #737-400-101AK, $39.99.
I had to use the MKT for my stainless Montado.
As you can see above, it's flat on the edge but that was easy to fix by polishing to a nice Colt curvature, below:
