Iron values do not change for items that are not listed in the default iron values datapack, such as minecraft:milk_bucket, trueprimepiece:piratesaber
Items that are affected by the datapack are items such as minecraft:iron_ingot, mineminenomi:cannon_ball
Below is the content used for iron_values.json:
{"minecraft:iron_ingot":5.0,"minecraft:iron_ore":1.0,"minecraft:iron_block":10.0,"minecraft:iron_nugget":1.0,"minecraft:bucket":1.0,"minecraft:shield":1.0,"minecraft:flint_and_steel":1.0,"minecraft:iron_horse_armor":1.0,"minecraft:shears":1.0,"mineminenomi:handcuffs":1.0,"mineminenomi:iron_box":1.0,"mineminenomi:bullet":1.0,"mineminenomi:cannon_ball":1.0,"mineminenomi:marine_sword":1.0,"mineminenomi:pirate_cutlass":1.0,"mineminenomi:pipe":1.0,"mineminenomi:scissors":1.0,"mineminenomi:kikoku":1.0,"mineminenomi:kiribachi":4.0,"mineminenomi:yoru":1.0,"mineminenomi:murakumogiri":1.0,"mineminenomi:hook":1.0,"mineminenomi:tonfa":1.0,"mineminenomi:bandit_knife":1.0,"mineminenomi:aces_knife":1.0,"mineminenomi:mihawks_knife":1.0,"mineminenomi:sandai_kitetsu":1.0,"mineminenomi:wado_ichimonji":1.0,"mineminenomi:nidai_kitetsu":1.0,"mineminenomi:shusui":1.0,"mineminenomi:enma":1.0,"mineminenomi:ame_no_habakiri":1.0,"mineminenomi:soul_solid":1.0,"mineminenomi:durandal":1.0,"mineminenomi:mace":1.0,"mineminenomi:daisenso":1.0,"mineminenomi:ace":1.0,"mineminenomi:mogura":1.0,"mineminenomi:daltons_spade":1.0,"mineminenomi:flintlock":1.0,"mineminenomi:senriku":1.0,"mineminenomi:bazooka":1.0,"mineminenomi:walker":1.0,"trueprimepiece:piratesaber":1.0,"trueprimepiece:katana":1.0,"trueprimepiece:durandal":1.0,"mineminenomi:cat_claws":1.0,"trueprimepiece:iron_mace":1.0,"trueprimepiece:hollow_scythe":1.0,"mineminenomi:cannon":1.0,"minecraft:milk_bucket":1.0}