Originally Posted by MistWolf

Remove the trigger, clean and lube with grease before reinstalling. Apply grease to all sear surfaces, pin holes and the bottom curve of the hammer. Any clean grease will do.

Keep a couple of spare extractor springs on hand. In my experience, Colt extractor springs have the longest life and are the most reliable.

Keep a complete spare bolt carrier group on hand. It will save you a lot of headaches.

S&W muzzle devices are longer and heavier than they need to be. Spending ten bucks or so for an A2 birdcage replacement is worth it.

Carbine weight buffers are too light. If your AR has a carbine weight, I suggest replacing it with an H or H2 buffer. H buffers have an "H" stamped I the face. The H2 has an "H2" stamp. Carbine buffers have no stamp.

The rest of it is shooting