diff --git a/lib/cannery/ammo.ex b/lib/cannery/ammo.ex
index 3c62ab6..0be8e86 100644
--- a/lib/cannery/ammo.ex
+++ b/lib/cannery/ammo.ex
@@ -141,11 +141,8 @@ defmodule Cannery.Ammo do
   """
   @spec create_ammo_type(attrs :: map(), User.t()) ::
           {:ok, AmmoType.t()} | {:error, Changeset.t(AmmoType.new_ammo_type())}
-  def create_ammo_type(attrs \\ %{}, %User{id: user_id}) do
-    %AmmoType{}
-    |> AmmoType.create_changeset(attrs |> Map.put("user_id", user_id))
-    |> Repo.insert()
-  end
+  def create_ammo_type(attrs \\ %{}, %User{} = user),
+    do: %AmmoType{} |> AmmoType.create_changeset(user, attrs) |> Repo.insert()
 
   @doc """
   Updates a ammo_type.
diff --git a/lib/cannery/ammo/ammo_type.ex b/lib/cannery/ammo/ammo_type.ex
index d7593f7..c6e5012 100644
--- a/lib/cannery/ammo/ammo_type.ex
+++ b/lib/cannery/ammo/ammo_type.ex
@@ -105,10 +105,12 @@ defmodule Cannery.Ammo.AmmoType do
     ]
 
   @doc false
-  @spec create_changeset(new_ammo_type(), attrs :: map()) :: Changeset.t(new_ammo_type())
-  def create_changeset(ammo_type, attrs) do
+  @spec create_changeset(new_ammo_type(), User.t(), attrs :: map()) ::
+          Changeset.t(new_ammo_type())
+  def create_changeset(ammo_type, %User{id: user_id}, attrs) do
     ammo_type
-    |> cast(attrs, [:user_id | changeset_fields()])
+    |> change(user_id: user_id)
+    |> cast(attrs, changeset_fields())
     |> validate_required([:name, :user_id])
   end
 
diff --git a/priv/gettext/de/LC_MESSAGES/errors.po b/priv/gettext/de/LC_MESSAGES/errors.po
index 0289b9b..c764d28 100644
--- a/priv/gettext/de/LC_MESSAGES/errors.po
+++ b/priv/gettext/de/LC_MESSAGES/errors.po
@@ -188,7 +188,7 @@ msgstr ""
 "%{multiplier}"
 
 #, elixir-autogen, elixir-format
-#: lib/cannery/ammo.ex:407
+#: lib/cannery/ammo.ex:404
 msgid "Invalid multiplier"
 msgstr ""
 
diff --git a/priv/gettext/en/LC_MESSAGES/errors.po b/priv/gettext/en/LC_MESSAGES/errors.po
index dfb3bf9..6722c21 100644
--- a/priv/gettext/en/LC_MESSAGES/errors.po
+++ b/priv/gettext/en/LC_MESSAGES/errors.po
@@ -171,7 +171,7 @@ msgid "Invalid number of copies, must be between 1 and %{max}. Was %{multiplier}
 msgstr ""
 
 #, elixir-autogen, elixir-format
-#: lib/cannery/ammo.ex:407
+#: lib/cannery/ammo.ex:404
 msgid "Invalid multiplier"
 msgstr ""
 
diff --git a/priv/gettext/errors.pot b/priv/gettext/errors.pot
index e2d2ce8..bf7fb12 100644
--- a/priv/gettext/errors.pot
+++ b/priv/gettext/errors.pot
@@ -170,7 +170,7 @@ msgid "Invalid number of copies, must be between 1 and %{max}. Was %{multiplier}
 msgstr ""
 
 #, elixir-autogen, elixir-format
-#: lib/cannery/ammo.ex:407
+#: lib/cannery/ammo.ex:404
 msgid "Invalid multiplier"
 msgstr ""
 
diff --git a/priv/gettext/es/LC_MESSAGES/errors.po b/priv/gettext/es/LC_MESSAGES/errors.po
index d1a1f11..f741caa 100644
--- a/priv/gettext/es/LC_MESSAGES/errors.po
+++ b/priv/gettext/es/LC_MESSAGES/errors.po
@@ -181,7 +181,7 @@ msgid "Invalid number of copies, must be between 1 and %{max}. Was %{multiplier}
 msgstr ""
 
 #, elixir-autogen, elixir-format
-#: lib/cannery/ammo.ex:407
+#: lib/cannery/ammo.ex:404
 msgid "Invalid multiplier"
 msgstr ""
 
diff --git a/priv/gettext/fr/LC_MESSAGES/errors.po b/priv/gettext/fr/LC_MESSAGES/errors.po
index d391eff..d0809ba 100644
--- a/priv/gettext/fr/LC_MESSAGES/errors.po
+++ b/priv/gettext/fr/LC_MESSAGES/errors.po
@@ -187,7 +187,7 @@ msgid "Invalid number of copies, must be between 1 and %{max}. Was %{multiplier}
 msgstr "Nombre de copies invalide, doit être 1 et %{max}. Été %{multiplier}"
 
 #, elixir-autogen, elixir-format
-#: lib/cannery/ammo.ex:407
+#: lib/cannery/ammo.ex:404
 msgid "Invalid multiplier"
 msgstr ""