▁it , ▁" t rac ers ▁work ▁both ▁ways ". ▁Bright ▁trac ers ▁can ▁also ▁over wh elm ▁night - vision ▁devices , ▁rendering ▁them ▁useless . ▁Sub du ed ▁trac ers ▁burn ▁at ▁full ▁bright ness ▁after ▁a ▁hundred ▁or ▁more ▁yards ▁to ▁avoid ▁giving ▁away ▁the ▁gun ner ' s ▁position . ▁Dim ▁trac ers ▁burn ▁very ▁dim ly ▁but ▁are ▁clearly ▁visible ▁through ▁night - vision ▁equipment . ▁ ▁The ▁M 1 9 6 ▁trac er ▁cart ridge ▁( 5 4 - gra in ▁bullet ) ▁ 5 . 5 6 mm x 4 5 mm ▁NAT O ▁was ▁developed ▁for ▁the ▁original ▁M 1 6 ▁rif le ▁and ▁is ▁compatible ▁with ▁the ▁M 1 6 A 1 ▁bar rel ▁also ▁using ▁ 1 : 1 2 ▁rif ling ▁tw ist . ▁It ▁has ▁a ▁red ▁tip ▁and ▁is ▁designed ▁to ▁trace ▁out ▁to ▁ 5 0 0 ▁yards , ▁and ▁traject ory ▁match ▁the ▁M 1 9 3 ▁( 5 6 - gra in ) ▁ball ▁cart ridge , ▁which ▁has ▁no ▁tip ▁color . ▁ ▁Tra ject ory ▁match , ▁or ▁ball istic ▁match , ▁is ▁achieved ▁between ▁two ▁bul lets ▁of ▁slightly ▁different ▁weight ▁and ▁aer od ynamic ▁characteristics ▁by ▁adjust ing ▁the ▁cart ridge ▁prop ell ant ▁weight , ▁prop ell ant ▁type , ▁and ▁m uzz le ▁velocity , ▁to ▁remain ▁within ▁safe ▁pressure ▁limits , ▁yet ▁provide ▁each ▁bullet ▁with ▁a ▁traject ory ▁to ▁the ▁target ▁that ▁is ▁nearly ▁identical ▁over ▁all ▁atmos pher