diff --git a/include/ship.h b/include/ship.h
index 6e5c46a3..db6054d1 100644
--- a/include/ship.h
+++ b/include/ship.h
@@ -187,5 +187,6 @@ extern int shp_dchrg(struct shpstr *);
 extern int shp_fire(struct shpstr *);
 extern int shp_torp(struct shpstr *, int);
 extern double shp_fire_range(struct shpstr *);
+extern int shp_usable_guns(struct shpstr *);
 
 #endif
diff --git a/src/lib/commands/bomb.c b/src/lib/commands/bomb.c
index 72e4f1f9..a0f8c629 100644
--- a/src/lib/commands/bomb.c
+++ b/src/lib/commands/bomb.c
@@ -523,8 +523,8 @@ ship_bomb(struct emp_qelem *list, struct sctstr *target)
 	if ((plp->pcp->pl_flags & P_A) && !on_shiplist(shipno, head))
 	    continue;
 
-	shell = gun = 0;
-	gun = MIN(ship.shp_item[I_GUN], ship.shp_glim);
+	shell = 0;
+	gun = shp_usable_guns(&ship);
 	if (gun > 0) {
 	    shell = ship.shp_item[I_SHELL];
 	    if (shell <= 0)
diff --git a/src/lib/subs/aircombat.c b/src/lib/subs/aircombat.c
index 5ea34a68..53df1daa 100644
--- a/src/lib/subs/aircombat.c
+++ b/src/lib/subs/aircombat.c
@@ -837,8 +837,8 @@ ac_shipflak(struct emp_qelem *list, coord x, coord y)
 	rel = getrel(getnatp(ship.shp_own), plane_owner);
 	if (rel > HOSTILE)
 	    continue;
-	shell = gun = 0;
-	gun = MIN(ship.shp_item[I_GUN], ship.shp_glim);
+	shell = 0;
+	gun = shp_usable_guns(&ship);
 	if (gun) {
 	    shell = ship.shp_item[I_SHELL];
 	    if (shell <= 0) {
diff --git a/src/lib/subs/landgun.c b/src/lib/subs/landgun.c
index 617da772..4f0c018d 100644
--- a/src/lib/subs/landgun.c
+++ b/src/lib/subs/landgun.c
@@ -113,8 +113,7 @@ shp_fire(struct shpstr *sp)
 
     if (sp->shp_effic < 60)
 	return -1;
-    guns = sp->shp_glim;
-    guns = MIN(guns, sp->shp_item[I_GUN]);
+    guns = shp_usable_guns(sp);
     guns = MIN(guns, (sp->shp_item[I_MILIT] + 1) / 2);
     if (guns == 0)
 	return -1;
@@ -217,6 +216,15 @@ lnd_fire(struct lndstr *lp)
     return d;
 }
 
+/*
+ * Return number of guns ship SP can fire.
+ */
+int
+shp_usable_guns(struct shpstr *sp)
+{
+    return MIN(sp->shp_glim, sp->shp_item[I_GUN]);
+}
+
 /*
  * Return effective firing range for range factor RNG at tech TLEV.
  */
diff --git a/src/lib/subs/shpsub.c b/src/lib/subs/shpsub.c
index 0691a58d..dd0cdee6 100644
--- a/src/lib/subs/shpsub.c
+++ b/src/lib/subs/shpsub.c
@@ -877,7 +877,7 @@ shp_missile_defense(coord dx, coord dy, natid bombown, int hardtarget)
 	    continue;
 
 	/* now calculate the odds */
-	gun = MIN(ship.shp_item[I_GUN], ship.shp_glim);
+	gun = shp_usable_guns(&ship);
 	eff = ship.shp_effic / 100.0;
 	teff = ship.shp_tech / (ship.shp_tech + 200.0);
 	/* raise 4.5 for better interception -KHS */