Cat, I have that rifle. A friend gave it to me. It's surprisingly powerful and accurate (and an astounding value), but the trigger is brutally stiff on mine. I almost run out of breath before I can squeeze off a shot. Unfortunately, the trigger is hard to get to, and I think is unadjustable anyway.
That is unfortunate. I've never given the trigger pull any thought. Because I haven't noticed, I'm assuming it is not significantly different than any of my other rifles or shotguns.
This is my third one of these cheap rifles. All have been great. I lent one to a co-worker, and then we both moved in opposite geographical directions. It wasn't worth trying to retrieve. My father-in-law liked my second one so much for squirrels, I gave it to him. The one I have now is about two years old.