MOSSBERG AR-15 JM Pro Trigger Drop-In 4lb - $183.99 shipped with code "MDX"

I’ve used similar but lighter from other brands and they have acceptably short pre and post travel and crisp break. I’d expect the same here. Full weight mil-spec triggers will hide the fact that new rimfires don’t reliably go into battery. This trigger is listed at 4# which might possibly be enough to reliably ignite new rimfires, though they should be more accurate after break in. I don’t know if it would be reliable with Berdan primers but expect Mossberg would answer that question. I’d expect good function with boxer primers. The image suggests it actually uses the standard pins from a LPK which is really convenient. I’d probably buy one if I was building today but hope to hear from someone who’s used this one.