1000 lb DA trigger.

[LMWIS]

I was at the range today, and a gent was shooting a model 19 single action. When I asked, he said he didn't like the double action because it was too heavy. I tried it and the the trigger wasn't heavy, it was locked. It won't fire DA but it will fire SA. Any fix, or is this a trip to the smith?

 

[kudzu3]

Could be a number of things. May be a simple fix, but if not familiar with the innards, a trip to the smith is best.