This is my first command block tutorial so tell me what you think;

Grenades in vanilla MC
1. Set up a dummy scoreboard called "bomb"
2. set up a clock with command blocks or command block minecarts.
3. write this command in a comamnd block;
/execute @e[type=Snowball] ~ ~ ~ summon Arrow ~ ~ ~ {CustomName:grenade}
4. Write this command in anothe command block;
/scoreboard players remove @e[name=grenade] bomb 1
5. Write this command in another command block;
/scoreboard players add @e[name=grenade,OnGround:1] bomb 5
6. Write this command in another command block;
/kill @e[name=grenade,score_bomb_status=-2]
7. Write this command in another command block;
/execute @e[name=grenade,score_bomb_min=1] ~ ~ ~ summon PrimedTnt
8. Activate clock and make sure ALL command blocks are being activated at once.