AR'S LOWERS ARE THE SAME BUT WHO'S NAME IS ON THEM,ALL PART'S WORK IN ALL OF THEM LIKE DPMS,BUSHMASTER,RRA,AND SO ON.90% OF THE TIME ITS BAD AMMO OR A BAD SPRING THAT MAKE'S THEN NOT WORK.
AND THAT'S MY 2 CENT'S ON THAT.
Word to the wise. Never take advice from someone who types in all caps.