I tried a Jard in a AR15 5.56 , (a non-drop in model).
It would unexpectedly Double-Tapp on occasion .
Kept trying to adjust it out , then got frustrated. Pulled it out, Sold it, put a Timney 3 pound Drop-IN.($200+).
Been a Happy Customer Ever since !
Lucas Drop-Ins are another Nice Brand.($150+).