Background:
Glock 19, manufacturered and purchased new in 2006, 5,000-10,000 rounds thorugh it. Only modifications are Trijicon Night Sights, Glock Extended Slide Release, and a Siderlock Manual Safety. Cleaned every couple hundred rounds.
Problem:
Since installation of Siderlock Safety/Trigger, occasionally there will be a very distinct malfunction. I noticed this, because before installation, I virtually never had malfunctions.
-Only happens on the first shot after inserting a new magazine and racking the slide.
-Happens seemingly at random; about 1/4 of the time a new mag is inserted.
-The trigger does not act right. It feels as if it slips; not completely loose as if it were out of battery, and not a normal hammer drop as if everything was working properly. I can feel tension start up, then the tension lets go, there is a click (a different kind of click, not the usual dryfire sound) as the trigger "slips" and goes all the way back.
-I have checked; the gun is not out of battery, and the rounds are not duds. The firing pin is not making contact with the round in the chamber.
Solution:
I am not at all experienced in gunsmithing; I know as much as I have needed to get by so far. However, I have come up with a couple theories about the source of the problem.
-It is possible that the Siderlock Trigger/Safety is causing the problem, however it does not change anything internally, so mechanically it does not make sense that it would cause the problem.
-I think that more likely, is that I messed something up when I detail stripped the frame in order to swap triggers.
-Or, something completely unrelated has broken or become fouled.
Regardless of the source of the problem, I have no idea how to fix it. I will be going to a couple gun shops this evening to have someone look at it; if anyone could recommend somewhere or someone to take it to, it would be much appreciated.