This is book one in a series about a DEA agent named Jackson Fowler. The series is just called "Agents." The next two in the series, which appears to be all that ever appeared, were Pipeline and Shakedown. All were released at 3 to 4 month intervals in 1991, and then no more. Book 3 must have had a relatively low print run since I can't even find a cover pic for it and it is listed everywhere as "out of stock."
Nor can I find anything about the author. I found a fourth book supposedly by him, which is a nonfiction story called Kill the Major and not connected the agents series. I don't know if it's the same man or not. And it's quite possible the name is a house name anyway so there may not be a real life Paul Malone out there. The agents series is from Worldwide publishers, which appears to have been centered in the UK, particularly in Australia since this has an Australian copyright.
As for "Trigger Pull," I found this quite a good read. Say 3 and a half stars. The action level is high and I enjoyed the character, although the characterization here isn't particularly deep. But that's not typical of the genre anyway. The book begins with the protagonist, Fowler, investigating the death of a man who was once his partner in the police. He identifies some bad cops as the shooters but also wants the big drug dealer who those cops work for. A lot of the action involves people trying to kill Fowler to keep him from finding answers. Overall, I enjoyed it.
Another Gold Eagle series that didn't take, only lasting three books. Though it's quite good with Paul Malone being one of many of Mike Newton's pen names. A veteran of the Bolanverse, he knows how to write a quick moving action novel. In this Jack Fowler is a DEA agent who used to work in the narcotics unit at Miami Dade. His partner back in his narcotics days was killed and now he is looking to take on the drug boss and the dirty cops who killed him.
Recommended, a fun quick read looking forward to reading the other two.