I bought one and put the GRT-III trigger in it, but it just wouldn't work right. It was a hair trigger with no adjustment. I've not had this problem putting the GRT-III in my Gamo air rifles, but this one just didn't like it. By the time I modified it enough to have good trigger function, I had ruined it's ability to hold the safety under pressure. I had to file down the top flat plane that the first stage adjustment screw goes through to get it to sit right against the trigger strut. Otherwise, it pushed the strut up such that it was almost at the release point as soon as the trigger blade was installed. I made sure the strut was centered and everything. I'm not sure what the deal was, but I had to go back to the stock trigger, which has turned out to be not so bad.
