If they are 11&3/4 inches long then they are more than likely hand guards for M1 Garrand not carbine. The carbine hand guards are about 6 inches long.
In the picture in the above post it looks like an assortment of K and J frame grips. The smaller shorter ones are for J frames. The larger for K or N frame models. The top far right looks like wood grip panels for a 1911 frame. The square set on the bottom I am unsure of possibly for a S&W semi auto. Or a Sig Sauer.
No matter how many times you do it and nothing happens it only takes something going wrong one time to kill you.