diff --git a/src/app/shipyard/Calculations.js b/src/app/shipyard/Calculations.js
index b7a2f22a..aa995eed 100644
--- a/src/app/shipyard/Calculations.js
+++ b/src/app/shipyard/Calculations.js
@@ -585,7 +585,7 @@ export function armourMetrics(ship) {
       hullThermDmg = hullThermDmg * (1 - slot.m.getThermalResistance());
       hullCausDmg = hullCausDmg * (1 - slot.m.getCausticResistance());
     }
-    if (slot.m && slot.m.grp == 'mrp') {
+    if (slot.m && (slot.m.grp == 'mrp' || slot.m.grp == 'gmrp')) {
       moduleArmour += slot.m.getIntegrity();
       moduleProtection = moduleProtection * (1 - slot.m.getProtection());
     }
diff --git a/src/app/shipyard/Ship.js b/src/app/shipyard/Ship.js
index 19bfdf64..87be0b90 100755
--- a/src/app/shipyard/Ship.js
+++ b/src/app/shipyard/Ship.js
@@ -937,7 +937,12 @@ export default class Ship {
     let epsChanged = n && n.getEps() || old && old.getEps();
     let hpsChanged = n && n.getHps() || old && old.getHps();
 
-    let armourChange = (slot === this.bulkheads) || (n && n.grp === 'hr') || (n && n.grp === 'ghrp') || (old && old.grp === 'hr') || (old && old.grp === 'ghrp') || (n && n.grp === 'mrp') || (old && old.grp === 'mrp') || (n && n.grp == 'mahr') || (old && old.grp == 'mahr');
+    let armourChange = (slot === this.bulkheads) ||
+      (n && n.grp === 'hr') || (old && old.grp === 'hr') ||
+      (n && n.grp === 'ghrp') || (old && old.grp === 'ghrp') ||
+      (n && n.grp == 'mahr') || (old && old.grp == 'mahr') ||
+      (n && n.grp === 'mrp') || (old && old.grp === 'mrp') ||
+      (n && n.grp === 'gmrp') || (old && old.grp == 'gmrp');
 
     let shieldChange = (n && n.grp === 'bsg') || (old && old.grp === 'bsg') || (n && n.grp === 'psg') || (old && old.grp === 'psg') || (n && n.grp === 'sg') || (old && old.grp === 'sg') || (n && n.grp === 'sb') || (old && old.grp === 'sb') || (old && old.grp === 'gsrp') || (n && n.grp === 'gsrp');