diff --git a/src/lib/components/Field.svelte b/src/lib/components/Field.svelte
index 68c73cc..506ea34 100644
--- a/src/lib/components/Field.svelte
+++ b/src/lib/components/Field.svelte
@@ -1,4 +1,4 @@
-<div>
+<div class="field">
   {#if label}
     <label>{label}</label>
   {/if}
diff --git a/src/lib/components/ShipEdit/Weaponry.story.svelte b/src/lib/components/ShipEdit/Weaponry.story.svelte
new file mode 100644
index 0000000..f62f327
--- /dev/null
+++ b/src/lib/components/ShipEdit/Weaponry.story.svelte
@@ -0,0 +1,17 @@
+<Hst.Story>
+  <Weaponry {weapons} />
+</Hst.Story>
+
+<script>
+  export let Hst;
+  import Weaponry from "./Weaponry.svelte";
+  import u from "@yanick/updeep-remeda";
+  import { weaponTypes } from "$lib/store/ship/weaponry/rules";
+  import Changelog from "../Changelog.svelte";
+
+  const weapons = [
+    weaponTypes.find(u.matches({ type: "beam" })).initial,
+    weaponTypes.find(u.matches({ type: "submunition" })).initial,
+  ].map((specs, id) => ({ specs, id }));
+  console.log(weapons);
+</script>
diff --git a/src/lib/components/ShipEdit/Weaponry.svelte b/src/lib/components/ShipEdit/Weaponry.svelte
index 5d133ab..6ff4423 100644
--- a/src/lib/components/ShipEdit/Weaponry.svelte
+++ b/src/lib/components/ShipEdit/Weaponry.svelte
@@ -2,14 +2,12 @@
   <Firecons {...firecons} />
 
   <ADFC {...adfc} />
-  <!--
 
-    <AddWeapon />
+  <AddWeapon />
 
-    {#each weapons as weapon (weapon.id)}
-        <Weapon {weapon} id={weapon.id} />
-    {/each}
-    -->
+  {#each weapons as weapon (weapon.id)}
+    <Weapon {...weapon} />
+  {/each}
 </Section>
 
 <script>
@@ -22,17 +20,14 @@
 
   import Firecons from "./Weaponry/Firecons.svelte";
   import ADFC from "./Weaponry/ADFC.svelte";
+  import AddWeapon from "./Weaponry/AddWeapon.svelte";
 
   export let firecons = {};
   export let adfc = {};
-  /*
 
-    import AddWeapon from './AddWeapon.svelte';
-    import Weapon from './Weapon/index.svelte';
+  import Weapon from "./Weaponry/Weapon/index.svelte";
 
-
-export let weapons = [];
-*/
+  export let weapons = [];
 </script>
 
 <style>
diff --git a/src/lib/components/ShipEdit/Weaponry/AddWeapon.svelte b/src/lib/components/ShipEdit/Weaponry/AddWeapon.svelte
index 19a85b0..ce30242 100644
--- a/src/lib/components/ShipEdit/Weaponry/AddWeapon.svelte
+++ b/src/lib/components/ShipEdit/Weaponry/AddWeapon.svelte
@@ -1,24 +1,25 @@
-<Field label="weapon type">
-  <select bind:value={type}>
-    {#each weaponTypes as weapon (weapon.type)}
-      <option value={weapon.type}>{weapon.name}</option>
-    {/each}
-  </select>
-
+<div>
+  <Field label="">
+    <select bind:value={type}>
+      {#each weaponTypes as weapon (weapon.type)}
+        <option value={weapon.type}>{weapon.name}</option>
+      {/each}
+    </select>
+  </Field>
   <button class="button small primary" on:click={addWeapon}>add weapon</button>
-</Field>
+</div>
 
 <script>
   import { getContext } from "svelte";
   import Field from "../../Field.svelte";
 
-  import { weaponTypes } from "$lib/shipDux/weaponry/weapons";
+  import { weaponTypes } from "$lib/store/ship/weaponry/rules";
 
-  export let ship = getContext("ship");
+  export let api = getContext("api");
 
-  let type = weaponTypes[0].value;
+  let type = weaponTypes[0].type;
 
-  const addWeapon = () => ship.dispatch.addWeapon(type);
+  const addWeapon = () => api?.dispatch?.addWeapon?.(type);
 </script>
 
 <style>
@@ -26,4 +27,17 @@
     width: inherit;
     display: inline-block;
   }
+  button {
+    width: inherit;
+    display: inline-block;
+  }
+  div :global(.field) {
+    display: flex;
+    margin-right: 2em;
+  }
+  div {
+    display: flex;
+    margin-left: 5em;
+    margin-bottom: 2em;
+  }
 </style>
diff --git a/src/lib/components/ShipEdit/Weaponry/Weapon/Arcs.story.svelte b/src/lib/components/ShipEdit/Weaponry/Weapon/Arcs.story.svelte
new file mode 100644
index 0000000..59dc606
--- /dev/null
+++ b/src/lib/components/ShipEdit/Weaponry/Weapon/Arcs.story.svelte
@@ -0,0 +1,8 @@
+<Hst.Story>
+  <Arcs />
+</Hst.Story>
+
+<script>
+  export let Hst;
+  import Arcs from "./Arcs.svelte";
+</script>
diff --git a/src/lib/components/ShipEdit/Weaponry/Weapon/Arcs.svelte b/src/lib/components/ShipEdit/Weaponry/Weapon/Arcs.svelte
index 6657c21..effd42c 100644
--- a/src/lib/components/ShipEdit/Weaponry/Weapon/Arcs.svelte
+++ b/src/lib/components/ShipEdit/Weaponry/Weapon/Arcs.svelte
@@ -1,10 +1,10 @@
 <svg width="{size}px" height="{size}px">
-  {#each all_arcs as arc (arc)}
+  {#each arcs as arc (arc)}
     <Arc
       {arc}
       radius={size / 2}
       active={selected.includes(arc)}
-      on:click={() => click_arc(arc)}
+      on:click={() => clickArc(arc)}
     />
   {/each}
   <circle cx="50%" cy="50%" r={size / 3} />
@@ -12,17 +12,17 @@
 </svg>
 
 <script>
-  import Arc from "./Arc.svelte";
   import { createEventDispatcher } from "svelte";
 
-  const all_arcs = ["FS", "F", "FP", "AP", "A", "AS"];
+  import { arcs } from "$lib/store/ship/weaponry/rules";
+  import Arc from "./Arc.svelte";
 
   export let selected = [];
   export let size = 60;
 
   const dispatch = createEventDispatcher();
 
-  const click_arc = (arc) => dispatch("click_arc", arc);
+  const clickArc = (arc) => dispatch("clickArc", arc);
 </script>
 
 <style>
diff --git a/src/lib/components/ShipEdit/Weaponry/Weapon/Beam/index.svelte b/src/lib/components/ShipEdit/Weaponry/Weapon/Beam/index.svelte
index 28569e5..f2fede6 100644
--- a/src/lib/components/ShipEdit/Weaponry/Weapon/Beam/index.svelte
+++ b/src/lib/components/ShipEdit/Weaponry/Weapon/Beam/index.svelte
@@ -1,80 +1,93 @@
 <label>beam</label>
 
 <Field label="beam class">
-    <select bind:value={weaponClass}>
-        <option value={1}>1</option>
-        <option value={2}>2</option>
-        <option value={3}>3</option>
-        <option value={4}>4</option>
-    </select>
+  <select bind:value={weaponClass}>
+    <option value={1}>1</option>
+    <option value={2}>2</option>
+    <option value={3}>3</option>
+    <option value={4}>4</option>
+  </select>
 </Field>
 
 <Field label="arcs">
-    <select bind:value={nbrArcs}>
-        {#each arc_options[weaponClass] || [] as nbrArcs (nbrArcs)}
-            <option>{nbrArcs}</option>
-        {/each}
-    </select>
+  <select bind:value={nbrArcs}>
+    {#each arc_options[weaponClass] || [] as nbrArcs (nbrArcs)}
+      <option>{nbrArcs}</option>
+    {/each}
+  </select>
 </Field>
 
-<Arcs selected={arcs} on:click_arc={({ detail }) => setArcs(detail)} />
+<Arcs selected={arcs} on:clickArc={({ detail }) => setArcs(detail)} />
 
 <script>
-    import { getContext } from "svelte";
+  import { getContext } from "svelte";
+  import * as R from "remeda";
 
-    import Arcs from "../Arcs.svelte";
-    import ShipItem from "$lib/components/ShipItem.svelte";
-    import Field from "$lib/components/Field.svelte";
+  import Arcs from "../Arcs.svelte";
+  import ShipItem from "$lib/components/ShipItem.svelte";
+  import Field from "$lib/components/Field.svelte";
 
-    import { createEventDispatcher } from "svelte";
+  import { createEventDispatcher } from "svelte";
+  import memoize from "memoize-one";
 
-    const all_arcs = ["FS", "F", "FP", "AP", "A", "AS"];
+  const all_arcs = ["FS", "F", "FP", "AP", "A", "AS"];
 
-    export let weaponClass = 1;
-    export let arcs = ["F"];
+  export let weaponClass = 1;
+  export let arcs = ["F"];
 
-    let arc_options = {
-        1: [6],
-        2: [3, 6],
-        3: [1, 2, 3, 4, 5, 6, "broadside"],
-        4: [1, 2, 3, 4, 5, 6, "broadside"],
-    };
+  let arc_options = {
+    1: [6],
+    2: [3, 6],
+    3: [1, 2, 3, 4, 5, 6, "broadside"],
+    4: [1, 2, 3, 4, 5, 6, "broadside"],
+  };
 
-    $: arcsCaches = arcs.join(',');
+  let nbrArcs = arcs.length;
 
-    let nbrArcs = arcs.length;
+  $: if (!arc_options[weaponClass].includes(nbrArcs)) {
+    nbrArcs = arc_options[weaponClass][0];
+    console.log({ nbrArcs, label: "in if" });
+  }
 
-    $: if (!arc_options[weaponClass].includes(nbrArcs)) {
-        nbrArcs = arc_options[weaponClass][0];
-        console.log({nbrArcs, label:"in if"})
+  const broadside = ["FS", "FP", "AP", "AS"];
+
+  function setArcs(firstArc) {
+    console.log(firstArc);
+    let newArcs;
+    if (nbrArcs === "broadside") {
+      newArcs = broadside;
+    } else {
+      let first_index = all_arcs.findIndex((arc) => arc === firstArc);
+      if (first_index === -1) first_index = 0;
+
+      newArcs = Array.from({ length: nbrArcs }).map(
+        (_dummy, i) => all_arcs[(first_index + i) % all_arcs.length]
+      );
     }
 
-    const broadside = ["FS", "FP", "AP", "AS"];
-
-
-    function setArcs(firstArc) {
-        if (nbrArcs === "broadside") {
-            arcs = broadside;
-            return;
-        }
-            let first_index = all_arcs.findIndex((arc) =>  arc === firstArc);
-            if (first_index === -1) first_index = 0;
-
-            arcs = Array.from({length: nbrArcs}).map(
-                (_dummy,i) => all_arcs[(first_index + i) % all_arcs.length]
-            );
-        arcsCaches = arcs.join(',');
+    $: console.log({ newArcs, arcs });
+    if (
+      arcs.length !== newArcs.length ||
+      arcs.length !== R.intersection(arcs, newArcs).length
+    ) {
+      arcs = newArcs;
     }
+  }
 
-    $: if (arcs.length !== nbrArcs) setArcs(arcs[0]);
+  $: if (arcs.length !== nbrArcs) setArcs(arcs[0]);
 
-    $: console.log("it changed!", arcs)
-    $: console.log("it changed!", arcsCaches)
+  $: console.log("it changed!", arcs);
 
-    const dispatch = createEventDispatcher();
+  const dispatch = createEventDispatcher();
 
-    $: dispatch("change", {
-            weaponClass,
-            arcs: arcsCaches.split(','),
-        });
+  let i = 5;
+
+  const memoChange = memoize((weaponClass, ...arcs) =>
+    dispatch("change", {
+      weaponClass,
+      arcs,
+    })
+  );
+
+  $: memoChange(weaponClass, ...arcs);
 </script>
diff --git a/src/lib/components/ShipEdit/Weaponry/Weapon/Needle.svelte b/src/lib/components/ShipEdit/Weaponry/Weapon/Needle.svelte
index cdb17fd..d98a39f 100644
--- a/src/lib/components/ShipEdit/Weaponry/Weapon/Needle.svelte
+++ b/src/lib/components/ShipEdit/Weaponry/Weapon/Needle.svelte
@@ -1,27 +1,14 @@
 <label>needle weapon</label>
 
-<Arcs selected={[arc]} on:click_arc={({ detail }) => click_arc(detail)} />
+<Arcs selected={[arc]} on:clickArc={({ detail }) => clickArc(detail)} />
 
-<script>
-  import { getContext } from "svelte";
+<script lang="ts">
   import Arcs from "./Arcs.svelte";
   import { createEventDispatcher } from "svelte";
 
-  const all_arcs = ["FS", "F", "FP", "AP", "A", "AS"];
-
   export let arc = "F";
 
   const dispatch = createEventDispatcher();
 
-  const click_arc = (arc) => {
-        dispatch("change",{arc});
-  };
+  const clickArc = (arc) => dispatch("change", { arc });
 </script>
-
-<style>
-  .arc {
-    display: flex;
-    flex-direction: column;
-    margin-right: 1em;
-  }
-</style>
diff --git a/src/lib/components/ShipEdit/Weaponry/Weapon/Submunition.svelte b/src/lib/components/ShipEdit/Weaponry/Weapon/Submunition.svelte
index 070b55a..584d318 100644
--- a/src/lib/components/ShipEdit/Weaponry/Weapon/Submunition.svelte
+++ b/src/lib/components/ShipEdit/Weaponry/Weapon/Submunition.svelte
@@ -1,19 +1,16 @@
 <label>submunition pack</label>
 
-<Arcs selected={[arc]} on:click_arc={({ detail }) => click_arc(detail)} />
+<Arcs selected={[arc]} on:clickArc={({ detail }) => clickArc(detail)} />
 
 <script>
-  import { getContext } from "svelte";
   import Arcs from "./Arcs.svelte";
   import { createEventDispatcher } from "svelte";
 
-  const all_arcs = ["FS", "F", "FP", "AP", "A", "AS"];
-
   export let arc = "F";
 
   const dispatch = createEventDispatcher();
 
-  const click_arc = (arc) => {
-        dispatch("change",{arc});
+  const clickArc = (arc) => {
+    dispatch("change", { arc });
   };
 </script>
diff --git a/src/lib/components/ShipEdit/Weaponry/Weapon/index.svelte b/src/lib/components/ShipEdit/Weaponry/Weapon/index.svelte
index 0f799df..adb081d 100644
--- a/src/lib/components/ShipEdit/Weaponry/Weapon/index.svelte
+++ b/src/lib/components/ShipEdit/Weaponry/Weapon/index.svelte
@@ -1,15 +1,8 @@
 <ShipItem {...reqs}>
   <div class="weapon_row">
-    <button
-      class="button small red remove"
-      on:click={remove}>remove
-    </button>
+    <button class="button small red remove" on:click={remove}>remove </button>
 
-    <svelte:component
-      this={component[type]}
-      {...weapon}
-      on:change={update}
-    />
+    <svelte:component this={component[type]} {...specs} on:change={update} />
   </div>
 </ShipItem>
 
@@ -19,34 +12,33 @@
   import Arc from "./Arc.svelte";
   import ShipItem from "$lib/components/ShipItem.svelte";
   import Field from "$lib/components/Field.svelte";
-   import Beam from "./Beam/index.svelte";
-   import Submunition from "./Submunition.svelte";
-   import PointDefenceSystem from "./PDS.svelte";
-   import Scattergun from "./Scattergun.svelte";
+  import Beam from "./Beam/index.svelte";
+  import Submunition from "./Submunition.svelte";
+  import PointDefenceSystem from "./PDS.svelte";
+  import Scattergun from "./Scattergun.svelte";
   import Needle from "./Needle.svelte";
 
   const component = {
-     beam: Beam,
-     submunition: Submunition,
-     pds: PointDefenceSystem,
-     scattergun: Scattergun,
-     needle: Needle,
+    beam: Beam,
+    submunition: Submunition,
+    pds: PointDefenceSystem,
+    scattergun: Scattergun,
+    needle: Needle,
   };
 
-  export let weapon = {};
-  $: reqs = weapon.reqs;
+  export let reqs = {};
+  export let specs = {};
   export let id;
 
-  const ship = getContext("ship");
+  const api = getContext("api");
 
-  $: type = weapon.type;
+  $: type = specs.type;
 
-  const remove = () => ship.dispatch.removeWeapon(id);
+  const remove = () => api?.dispatch?.removeWeapon?.(id);
 
   const update = ({ detail }) => {
-      console.log({id,type})
-    ship.dispatch.setWeapon({
-      id,
+    console.log({ id, type });
+    api?.dispatch?.setWeapon?.(id, {
       type,
       ...detail,
     });
@@ -54,6 +46,9 @@
 </script>
 
 <style>
+  button {
+    width: inherit;
+  }
   .weapon {
     display: flex;
     align-items: center;
diff --git a/src/lib/store/ship.test.ts b/src/lib/store/ship.test.ts
index 3e52631..429dba6 100644
--- a/src/lib/store/ship.test.ts
+++ b/src/lib/store/ship.test.ts
@@ -47,4 +47,11 @@ test("kicking the tires", () => {
       mass: 6,
     },
   });
+
+  store.dispatch.addWeapon("beam");
+  expect(store.getState().weaponry.weapons[0]).toEqual({
+    id: 1,
+    reqs: { cost: 3, mass: 1 },
+    specs: { arcs: ["F"], type: "beam", weaponClass: 1 },
+  });
 });
diff --git a/src/lib/store/ship.ts b/src/lib/store/ship.ts
index 10073aa..1fc8f0e 100644
--- a/src/lib/store/ship.ts
+++ b/src/lib/store/ship.ts
@@ -66,28 +66,40 @@ shipDux.addReaction((api) => {
   );
 });
 
-shipDux.addReaction((api) => (state) => {
-  let cost = 0;
-  let mass = 0;
+shipDux.addReaction((api) => {
+  const setShipReqs = memoize((cost, usedMass) =>
+    api.dispatch.setShipReqs({ cost, usedMass })
+  );
 
-  let subsystems = R.values(R.omit(state, ["identification"]));
+  return (state) => {
+    let cost = 0;
+    let mass = 0;
 
-  while (subsystems.length > 0) {
-    const subsystem = subsystems.shift();
-    if (typeof subsystem !== "object") continue;
+    let subsystems = R.values(R.omit(state, ["identification"]));
 
-    if (subsystem.reqs) {
-      cost += subsystem.reqs.cost;
-      mass += subsystem.reqs.mass;
+    while (subsystems.length > 0) {
+      const subsystem = subsystems.shift();
+      if (typeof subsystem !== "object") continue;
+
+      if (subsystem.reqs) {
+        cost += subsystem.reqs.cost ?? 0;
+        mass += subsystem.reqs.mass ?? 0;
+      }
+
+      subsystems.push(...Object.values(subsystem));
     }
 
-    subsystems.push(...Object.values(subsystem));
-  }
+    if (Number.isNaN(cost)) {
+      console.log(state.weaponry.weapons);
+      throw new Error();
+    }
 
-  api.dispatch.setShipReqs({ cost, usedMass: mass });
+    setShipReqs(cost, mass);
+  };
 });
 
 shipDux.addEffect((api) => (next) => (action) => {
+  console.log(action);
   next(action);
 });
 
diff --git a/src/lib/store/ship/weaponry/rules.ts b/src/lib/store/ship/weaponry/rules.ts
index 1230483..84c36c0 100644
--- a/src/lib/store/ship/weaponry/rules.ts
+++ b/src/lib/store/ship/weaponry/rules.ts
@@ -1,58 +1,94 @@
 import type { Reqs } from "$lib/shipDux/reqs";
 
+export const arcs = ["FS", "F", "FP", "AP", "A", "AS"] as const;
+
+export type Arc = (typeof arcs)[number];
+
+export type WeaponType = "beam";
+
+type Beam = {
+  type: "beam";
+  weaponClass: 1 | 2 | 3 | 4;
+  arcs: Arc[];
+};
+
+type Submunition = {
+  type: "submunition";
+  arc: Arc;
+};
+
+type PDS = {
+  type: "pds";
+};
+
+type Scattergun = { type: "scattergun" };
+
+type Needle = { type: "needle"; arc: Arc };
+
+export type Weapon = Beam | Submunition | PDS | Scattergun | Needle;
+
 export const weaponTypes = [
   {
-    name: "beam",
     type: "beam",
+    name: "beam",
     reqs: beamReqs,
     initial: {
+      type: "beam",
       weaponClass: 1,
-    },
+      arcs,
+    } as any as Beam,
   },
   {
-    name: "submunition pack",
     type: "submunition",
+    name: "submunition pack",
     reqs: { mass: 1, cost: 3 },
-    initial: { arc: "F" },
+    initial: { type: "submunition", arc: "F" } as Submunition,
   },
   {
     name: "point defence system",
     type: "pds",
     reqs: { mass: 1, cost: 3 },
-    initial: {},
+    initial: {
+      type: "pds",
+    },
   },
   {
     name: "scattergun",
     type: "scattergun",
     reqs: { mass: 1, cost: 4 },
-    initial: {},
+    initial: { type: "scattergun" },
   },
   {
     name: "needle weapon",
     type: "needle",
     reqs: { mass: 2, cost: 6 },
-    initial: { arc: "F" },
+    initial: { arc: "F", type: "needle" },
   },
 ];
 
 export function weaponReqs(weapon): Reqs {
   const { reqs } = weaponTypes.find((wt) => wt.type === weapon.type) || {};
 
-  if (!reqs) return {};
+  if (!reqs)
+    return {
+      cost: 0,
+      mass: 0,
+    };
 
   if (typeof reqs === "function") return reqs(weapon);
 
   return reqs;
 }
 
-const isBroadside = (arcs) => {
+const isBroadside = (arcs: Arc[]) => {
   if (arcs.length !== 4) return false;
 
   // that'd be A or F
   return !arcs.some((a) => a.length === 1);
 };
 
-function beamReqs({ weaponClass, arcs }) {
+function beamReqs({ weaponClass, arcs }: Beam) {
+  console.log(weaponClass, arcs);
   let mass;
 
   if (weaponClass === 1) {
diff --git a/src/lib/store/ship/weaponry/weapons.test.ts b/src/lib/store/ship/weaponry/weapons.test.ts
new file mode 100644
index 0000000..d5af186
--- /dev/null
+++ b/src/lib/store/ship/weaponry/weapons.test.ts
@@ -0,0 +1,39 @@
+import { weaponsDux } from "./weapons";
+import Debug from "debug";
+const debug = Debug("aotds:weapons");
+import u from "@yanick/updeep-remeda";
+process.env.UPDEEP_MODE = "dangerously_never_freeze";
+
+test("setWeapon", () => {
+  const store = weaponsDux.createStore();
+
+  store.dispatch.addWeapon("beam");
+  store.dispatch.addWeapon("submunition");
+
+  expect(store.getState()).toMatchObject([
+    {
+      specs: {
+        type: "beam",
+      },
+    },
+    {
+      specs: {
+        type: "submunition",
+      },
+    },
+  ]);
+
+  store.dispatch.setWeapon(1, {
+    type: "beam",
+    weaponClass: 2,
+    arcs: ["F", "FP", "FS"],
+  });
+  debug(store.getState());
+  expect(store.getState().find(u.matches({ id: 1 }))).toMatchObject({
+    specs: {
+      type: "beam",
+      weaponClass: 2,
+      arcs: ["FS", "F", "FP"],
+    },
+  });
+});
diff --git a/src/lib/store/ship/weaponry/weapons.ts b/src/lib/store/ship/weaponry/weapons.ts
index e37fb0e..85107e5 100644
--- a/src/lib/store/ship/weaponry/weapons.ts
+++ b/src/lib/store/ship/weaponry/weapons.ts
@@ -2,23 +2,16 @@ import type { Reqs } from "$lib/shipDux/reqs";
 import Updux from "updux";
 import u from "@yanick/updeep-remeda";
 import * as R from "remeda";
-import { weaponReqs } from "./rules";
-import { nanoid } from "@reduxjs/toolkit";
+import { weaponReqs, weaponTypes, type WeaponType, type Weapon } from "./rules";
 
-type Weapon = {
-  weaponClass: string;
-  arcs?: unknown[];
-  type: string;
-};
-
-type IndexedWeapon = { id: string; reqs: Reqs; specs: Weapon };
+type IndexedWeapon = { id: number; reqs: Reqs; specs: Weapon };
 
 export const weaponsDux = new Updux({
   initialState: [] as IndexedWeapon[],
   actions: {
     removeWeapon: (id: string) => id,
     setWeapon: (id: string, specs: Weapon) => ({ id, specs }),
-    addWeapon: (specs: Weapon) => specs,
+    addWeapon: (type: WeaponType) => type,
   },
 });
 
@@ -26,20 +19,35 @@ weaponsDux.addMutation(weaponsDux.actions.removeWeapon, (id) =>
   R.reject(u.matches({ id }))
 );
 
-weaponsDux.addMutation(
-  weaponsDux.actions.setWeapon,
-  ({ id, specs }) =>
-    (state) => {
-      const weapon = state.find(u.matches({ id }));
-      if (!weapon) return;
-      weapon.specs = specs;
-      weapon.reqs = weaponReqs(specs);
-    }
+// TODO not needed anymore
+const mergeArcs = (newArcs) => (original) => {
+  if (original === undefined) return undefined;
+
+  let merged = u.filter(original, (a) => newArcs.includes(a));
+
+  let toAdd = newArcs.filter((a) => !merged.includes(a));
+  if (toAdd.length) return [...merged, ...toAdd];
+
+  return merged;
+};
+
+weaponsDux.addMutation(weaponsDux.actions.setWeapon, ({ id, specs }) =>
+  u.map(
+    u.if(u.matches({ id }), {
+      specs: {
+        ...specs,
+        arcs: mergeArcs((specs as any).arcs),
+      },
+      reqs: weaponReqs(specs),
+    })
+  )
 );
 
-weaponsDux.addMutation(weaponsDux.actions.addWeapon, (specs) => (state) => {
+weaponsDux.addMutation(weaponsDux.actions.addWeapon, (type) => (state) => {
+  const specs = weaponTypes.find(u.matches({ type }))?.initial ?? {};
+  const id = 1 + Math.max(0, ...state.map(R.prop("id")));
   state.push({
-    id: nanoid(),
+    id,
     specs,
     reqs: weaponReqs(specs),
   });