M27-5 DA hitch

[Les Greevy]

I recently got a new to me S&W 27-5 that has been shot very little. I installed Wolfe reduced power hammer spring and 13 lb. trigger return spring that resulted in a very nice DA pull of about 8 lbs. on 5 of the 6 chambers of the cylinder. On one chamber I get a hitch about 2/3 through the DA pull and trigger gauge jumps up about 2 lbs. When cycled with the chamber open all is fine. When open cylinder spins fine. I suspect an issue with the ratchet but upon inspection I see nothing different. Because this gun has been shot very little do you think this will "wear in"? I lost my pistol smith a year ago. I live in central Pa.
Your thoughts please.

 

[armorer951]

Is the extractor rod tight? Any run out in the rod itself? I would suspect some interference between the end of the extractor rod and the front locking bolt.

Many other possibilities.

 

[Les Greevy]

M27 DA hitch

Armorer,
All looks fine up front.

 

[armorer951]

Perhaps not enough gauge or "end shake" between the cylinder assy and the yoke. Try removing the yoke screw and cycling the action to see if the interference goes away.

 

[Les Greevy]

By golly I think that is it.
I put Yoke screw back but not as tight and all is fine.

 

[armorer951]

The end of the yoke barrel (or the bottom of the cylinder cavity) may not be perfectly square, so you need a bit of gauge in there to make the cylinder rotate as designed. A bit of end shake is a necessary part of the design....usually .001" - .002" is enough.

I would imagine if you shoot it a bit the gauge will open up a little and it will be fine, even with the yoke screw tightened fully. Keep an eye on that screw though as it will have a tendency to back out during live and dry firing.

 

[Les Greevy]

Thanks Armorer.
I will follow your advice.