▁be ▁allowed ▁to ▁exp end ▁what ▁little ▁energy ▁it ▁has ▁in ▁the ▁air . ▁Some ▁blank ▁cart rid ges ▁are ▁cr imp ed ▁or ▁closed ▁at ▁the ▁end ▁and ▁do ▁not ▁contain ▁any ▁bullet ; ▁some ▁are ▁fully ▁loaded ▁cart rid ges ▁( without ▁bul lets ) ▁designed ▁to ▁prop el ▁rif le ▁gr en ades . ▁Note ▁that ▁blank ▁cart rid ges , ▁at ▁short ▁ranges , ▁can ▁be ▁le th al ▁due ▁to ▁the ▁force ▁of ▁the ▁expand ing ▁gas ▁– ▁numerous ▁trag ic ▁acc idents ▁have ▁occurred ▁with ▁blank ▁cart rid ges ▁( e . g ., ▁the ▁death ▁of ▁actor ▁Jon - E rik ▁H ex um ). ▁ ▁Pract ice : ▁Made ▁from ▁light weight ▁materials ▁like ▁rub ber , ▁w ax , ▁wood , ▁pl astic , ▁or ▁light weight ▁metal , ▁practice ▁bul lets ▁are ▁intended ▁for ▁short - range ▁target ▁work , ▁only . ▁Because ▁of ▁their ▁weight ▁and ▁low ▁velocity , ▁they ▁have ▁limited ▁range . ▁ ▁Pol ym er : ▁These ▁are ▁metal - pol ym er ▁compos ites , ▁generally ▁l ighter ▁and ▁higher ▁velocity ▁than ▁a ▁pure ▁metal ▁bullet ▁of ▁the ▁same ▁dimensions . ▁They ▁permit ▁unusual ▁designs ▁that ▁are ▁difficult ▁with ▁conventional ▁casting ▁or ▁l ath ing . ▁ ▁Less ▁le th al , ▁or ▁Less ▁than ▁L eth al : ▁Rub ber ▁bul lets , ▁pl astic ▁bul lets , ▁and ▁bean b ags ▁are ▁designed ▁to ▁be ▁non - le th al , ▁for ▁example ▁for ▁use ▁in