SP101 won't cock on single action

[Sisco]

Took my SP apart for a cleaning this morning. Put it all back together now I can't cock the hammer with my thumb for single action.
Double action works just fine, pull the trigger and everything moves as it should.
Watching everything work, it appears as though the cylinder latch isn't moving down far enough to release the cylinder, but why would it work double action and not single?
Since it was new this gun has been stiff when handcocking, hanging up now & then.

 

[4V50 Gary]

My first (thoughtless) response...

not assembled correctly? Disassemble, reassemble, test.

 

[Sisco]

Did that several times, everythings where it should be. Took it back to the dealer, he's a Davidsons distributor, should have a new one by this weekend.
Actually, since initially buying an SP, this will be the fourth time it's been returned and replaced with a new one.
Own several Rugers, never had a problem with any of the others.

 

[4V50 Gary]

Trigger group. Betcha anything something slipped out of place and was reassembled with it out of place.

 

[Sisco]

Didn't take the trigger group apart. With the exception of the transfer bar.