improving a trigger on an AR is almost as easy as changing underwear though....if you understand how they are built....This. I nabbed some ridiculous deals on BF on 2014- we're talking up to 60% off actual prices.
The DB15 deal isn't terrible, but you can definitely get better.
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Also, PSA stuff isn't bad, but it's a dime a dozen. Just like it was stated in the suppressor thread, you won't honestly notice a massive difference from one brand to another with similar mil-spec builds.
To an extent, it doesn't matter what you buy if the trigger is crap. I'm willing to bet money that any competent shooter will do better with a low-end AR with a high-end trigger than a high-end AR with a low-end trigger. Believe me on that.