[1.12.2] Modify deflected arrow distance for custom shield

I'm making a mod that adds enchantments to shield and I want to make one that increases the distance that deflected arrows travel. My plan is to use my custom shield class (that extends from ItemShield) to override the function that implements the arrow deflecting functionality, however I can't find it. All I could find related to "blocking" is this code:

this.addPropertyOverride(new ResourceLocation("blocking"), new IItemPropertyGetter()
        {
            @SideOnly(Side.CLIENT)
            public float apply(ItemStack stack, @Nullable World worldIn, @Nullable EntityLivingBase entityIn)
            {
                return entityIn != null && entityIn.isHandActive() && entityIn.getActiveItemStack() == stack ? 1.0F : 0.0F;
            }
        });
        BlockDispenser.DISPENSE_BEHAVIOR_REGISTRY.putObject(this, ItemArmor.DISPENSER_BEHAVIOR);

However I don't know how to deal with this. Any ideas?