diff --git a/include/land.h b/include/land.h
index f01d58f2..caf73062 100644
--- a/include/land.h
+++ b/include/land.h
@@ -167,6 +167,8 @@ extern int l_acc(struct lchrstr *, int);
 extern int l_dam(struct lchrstr *, int);
 extern int l_aaf(struct lchrstr *, int);
 
+extern int lnd_fire(struct lndstr *);
+
 /* src/lib/subs/lndsub.c */
 extern void lnd_sweep(struct emp_qelem *, int, int, natid);
 extern int lnd_interdict(struct emp_qelem *, coord, coord, natid);
diff --git a/include/prototypes.h b/include/prototypes.h
index c1b5948f..4a10d416 100644
--- a/include/prototypes.h
+++ b/include/prototypes.h
@@ -460,7 +460,7 @@ extern int lnd_prewrite(int, void *);
 /* landgun.c */
 extern double seagun(int, int);
 extern double fortgun(int, int);
-extern double landunitgun(int, int, int, int, int);
+extern double landunitgun(int, int);
 extern double effrange(int, double);
 extern double torprange(struct shpstr *);
 extern double fortrange(struct sctstr *);
diff --git a/src/lib/commands/mfir.c b/src/lib/commands/mfir.c
index 19f1885c..ca52e15a 100644
--- a/src/lib/commands/mfir.c
+++ b/src/lib/commands/mfir.c
@@ -79,8 +79,6 @@ multifire(void)
     coord x;
     coord y;
     int mil;
-    int gun;
-    int shell;
     int shots;
     int dam;
     int totaldefdam = 0;
@@ -173,8 +171,6 @@ multifire(void)
 		   fland.lnd_uid, LAND_MINFIREEFF);
 		continue;
 	    }
-	    resupply_commod(&fland, I_SHELL);	/* Get more shells */
-	    putland(fland.lnd_uid, &fland);
 	    if (fland.lnd_item[I_SHELL] == 0) {
 		pr("%s -- not enough shells\n", prland(&fland));
 		continue;
@@ -361,13 +357,11 @@ multifire(void)
 		pr("Unit %d cannot fire!\n", fland.lnd_uid);
 		continue;
 	    }
-	    if (fland.lnd_item[I_SHELL] == 0) {
-		pr("%s -- not enough shells\n", prland(&fland));
+	    if (fland.lnd_item[I_GUN] == 0) {
+		pr("%s -- not enough guns\n", prland(&fland));
 		continue;
 	    }
 
-	    shell = fland.lnd_item[I_SHELL];
-
 	    range = effrange(fland.lnd_frg, fland.lnd_tech);
 	    range2 = roundrange(range);
 	    pr("range is %d.00 (%.2f)\n", range2, range);
@@ -376,21 +370,16 @@ multifire(void)
 		range2 = -1;
 	    }
 
-	    gun = fland.lnd_item[I_GUN];
-	    if (gun <= 0) {
-		pr("%s -- not enough guns\n", prland(&fland));
+	    dam = lnd_fire(&fland);
+	    putland(fland.lnd_uid, &fland);
+	    if (dam < 0) {
+		pr("Klick!     ...\n");
 		continue;
 	    }
-
-	    dam = (int)landunitgun(fland.lnd_effic, fland.lnd_dam, gun,
-				   fland.lnd_ammo, shell);
 	    if (target == targ_ship) {
 		if (chance(fland.lnd_acc / 100.0))
 		    dam = ldround(dam / 2.0, 1);
 	    }
-	    use_supply(&fland);
-	    resupply_commod(&fland, I_SHELL);	/* Get more shells */
-	    putland(fland.lnd_uid, &fland);
 	} else {
 	    fx = fsect.sct_x;
 	    fy = fsect.sct_y;
@@ -716,7 +705,6 @@ quiet_bigdef(int attacker, struct emp_qelem *list, natid own, natid aown,
     struct sctstr firing;
     struct nstr_sect ns;
     struct flist *fp;
-    int gun, shell;
 
     if (own == 0)
 	return 0;
@@ -779,16 +767,6 @@ quiet_bigdef(int attacker, struct emp_qelem *list, natid own, natid aown,
     while (nxtitem(&ni, &land)) {
 	if (land.lnd_own == 0)
 	    continue;
-	if (land.lnd_effic < LAND_MINFIREEFF)
-	    continue;
-	/* Can't fire if on a ship */
-	if (land.lnd_ship >= 0)
-	    continue;
-	if (land.lnd_land >= 0)
-	    continue;
-	/* Gotta have military */
-	if (land.lnd_item[I_MILIT] < 1)
-	    continue;
 	/* Don't shoot yourself */
 	if (land.lnd_own == aown)
 	    continue;
@@ -803,27 +781,17 @@ quiet_bigdef(int attacker, struct emp_qelem *list, natid own, natid aown,
 	if (roundrange(erange) < ni.curdist)
 	    continue;
 
-	resupply_all(&land);
-	if (!has_supply(&land))
+	dam2 = lnd_fire(&land);
+	/* no putland(&land) because ammo is charged in use_ammo() */
+	if (dam2 < 0)
 	    continue;
 
-	gun = land.lnd_item[I_GUN];
-	shell = land.lnd_item[I_SHELL];
-
-	if (land.lnd_item[I_MILIT] == 0 || shell == 0 || gun == 0)
-	    continue;
-
-	dam2 = (int)landunitgun(land.lnd_effic, land.lnd_dam, gun,
-				land.lnd_ammo, shell);
-
 	(*nfiring)++;
 	fp = malloc(sizeof(struct flist));
 	memset(fp, 0, sizeof(struct flist));
 	fp->type = targ_unit;
 	fp->uid = land.lnd_uid;
 	add_to_fired_queue(&fp->queue, list);
-	use_supply(&land);
-	putland(land.lnd_uid, &land);
 	nreport(land.lnd_own, N_FIRE_BACK, player->cnum, 1);
 	dam += dam2;
     }
@@ -929,21 +897,17 @@ static void
 add_to_fired_queue(struct emp_qelem *elem, struct emp_qelem *list)
 {
     struct emp_qelem *qp;
-    struct flist *fp, *ep;
-    int bad = 0;
-
-    ep = (struct flist *)elem;
+    struct flist *fp;
+    struct flist *ep = (struct flist *)elem;
 
     /* Don't put them on the list if they're already there */
     for (qp = list->q_forw; qp != list; qp = qp->q_forw) {
 	fp = (struct flist *)qp;
-	if ((fp->type == targ_ship) && (fp->uid == ep->uid))
-	    bad = 1;
-	if ((fp->type != targ_ship) && (fp->x == ep->x) &&
-	    (fp->y == ep->y))
-	    bad = 1;
+	if (fp->type != targ_land && fp->uid == ep->uid)
+	    return;
+	if (fp->type != targ_land
+	    && fp->x == ep->x && fp->y == ep->y)
+	    return;
     }
-
-    if (!bad)
-	emp_insque(elem, list);
+    emp_insque(elem, list);
 }
diff --git a/src/lib/subs/landgun.c b/src/lib/subs/landgun.c
index 1cca07cd..fbaed6c5 100644
--- a/src/lib/subs/landgun.c
+++ b/src/lib/subs/landgun.c
@@ -35,6 +35,7 @@
 
 #include "damage.h"
 #include "file.h"
+#include "land.h"
 #include "nat.h"
 #include "optlist.h"
 #include "prototypes.h"
@@ -65,16 +66,14 @@ seagun(int effic, int guns)
 }
 
 double
-landunitgun(int effic, int shots, int guns, int ammo, int shells)
+landunitgun(int effic, int guns)
 {
-    double d = 0.0;
+    double d;
 
-    shots = MIN(shots, guns);
-    while (shots-- > 0)
+    d = 0.0;
+    while (guns--)
 	d += 5.0 + random() % 6;
     d *= effic * 0.01;
-    if (shells < ammo && ammo != 0)
-	d *= (double)shells / (double)ammo;
     return d;
 }
 
@@ -179,6 +178,45 @@ shp_torp(struct shpstr *sp, int usemob)
     return TORP_DAMAGE();
 }
 
+/*
+ * Fire from land unit LP.
+ * Use ammo, resupply if necessary.
+ * Return damage if the land unit fires, else -1.
+ */
+int
+lnd_fire(struct lndstr *lp)
+{
+    int guns, shells;
+    double d;
+    int ammo = lchr[lp->lnd_type].l_ammo;
+
+    if (CANT_HAPPEN(ammo == 0))
+	ammo = 1;
+
+    if (lp->lnd_effic < LAND_MINFIREEFF)
+	return -1;
+    if (lp->lnd_ship >= 0 || lp->lnd_land >= 0)
+	return -1;
+    if (lp->lnd_item[I_MILIT] == 0)
+	return -1;
+    guns = lp->lnd_dam;
+    guns = MIN(guns, lp->lnd_item[I_GUN]);
+    if (guns == 0)
+	return -1;
+    shells = lp->lnd_item[I_SHELL];
+    shells += supply_commod(lp->lnd_own, lp->lnd_x, lp->lnd_y,
+			    I_SHELL, ammo - shells);
+    if (shells == 0)
+	return -1;
+    d = landunitgun(lp->lnd_effic, guns);
+    if (shells < ammo) {
+	d *= (double)shells / (double)ammo;
+	ammo = shells;
+    }
+    lp->lnd_item[I_SHELL] = shells - ammo;
+    return d;
+}
+
 /*
  * Return effective firing range for range factor RNG at tech TLEV.
  */
diff --git a/src/lib/subs/lndsub.c b/src/lib/subs/lndsub.c
index a3ba6e90..a6b4636e 100644
--- a/src/lib/subs/lndsub.c
+++ b/src/lib/subs/lndsub.c
@@ -1128,37 +1128,21 @@ lnd_support(natid victim, natid attacker, coord x, coord y, int defending)
     struct nstr_item ni;
     struct lndstr land;
     int rel, rel2;
-    double dam = 0.0;
+    int dam, dam2;
     int dist;
-    int shell;
-    int gun;
     int range;
 
+    dam = 0;
     snxtitem_all(&ni, EF_LAND);
     while (nxtitem(&ni, &land)) {
-	if (land.lnd_dam == 0)
-	    continue;
 	if ((land.lnd_x == x) && (land.lnd_y == y))
 	    continue;
-	if (land.lnd_ship >= 0)
-	    continue;
-	if (land.lnd_land >= 0)
-	    continue;
-	if (land.lnd_effic < LAND_MINFIREEFF)
-	    continue;
-	/* Do we have mil? */
-	if (land.lnd_item[I_MILIT] <= 0)
-	    continue;
 	rel = getrel(getnatp(land.lnd_own), attacker);
 	rel2 = getrel(getnatp(land.lnd_own), victim);
 	if ((land.lnd_own != attacker) &&
 	    ((rel != ALLIED) || (rel2 != AT_WAR)))
 	    continue;
 
-	/* do we have supplies? */
-	if (!has_supply(&land))
-	    continue;
-
 	/* are we in range? */
 	dist = mapdist(land.lnd_x, land.lnd_y, x, y);
 
@@ -1166,31 +1150,26 @@ lnd_support(natid victim, natid attacker, coord x, coord y, int defending)
 	if (dist > range)
 	    continue;
 
-	shell = land.lnd_item[I_SHELL];
-	gun = land.lnd_item[I_GUN];
-
-	if (shell == 0 || gun == 0)
+	dam2 = lnd_fire(&land);
+	putland(land.lnd_uid, &land);
+	if (dam2 < 0)
 	    continue;
 
-	use_supply(&land);
 	if (defending)
 	    nreport(land.lnd_own, N_FIRE_BACK, victim, 1);
 	else
 	    nreport(land.lnd_own, N_FIRE_L_ATTACK, victim, 1);
-	if (roll(100) < land.lnd_acc) {
-	    dam += landunitgun(land.lnd_effic, land.lnd_dam, gun,
-			       land.lnd_ammo, shell) / 2;
-	} else {
-	    dam += landunitgun(land.lnd_effic, land.lnd_dam, gun,
-			       land.lnd_ammo, shell);
-	}
+	if (roll(100) < land.lnd_acc)
+	    dam2 /= 2;
+	dam += dam2;
 	if (land.lnd_own != attacker)
 	    wu(0, land.lnd_own,
 	       "%s supported %s at %s\n",
 	       prland(&land), cname(attacker), xyas(x, y, land.lnd_own));
     }
-    return (int)dam;
+    return dam;
 }
+
 int
 lnd_can_attack(struct lndstr *lp)
 {
diff --git a/src/lib/subs/mission.c b/src/lib/subs/mission.c
index 1f8e9d73..1e92f77c 100644
--- a/src/lib/subs/mission.c
+++ b/src/lib/subs/mission.c
@@ -411,7 +411,7 @@ perform_mission(coord x, coord y, natid victim, struct emp_qelem *list,
     struct plchrstr *pcp;
     int dam = 0, dam2, mission_flags, tech;
     natid plane_owner = 0;
-    int gun, shell, md, range, air_dam = 0;
+    int md, range, air_dam = 0;
     double prb, hitchance, vrange;
 
     getsect(x, y, &sect);
@@ -430,9 +430,6 @@ perform_mission(coord x, coord y, natid victim, struct emp_qelem *list,
 	if (glp->thing->ef_type == EF_LAND) {
 	    lp = (struct lndstr *)glp->thing;
 
-	    if (lp->lnd_effic < LAND_MINFIREEFF)
-		continue;
-
 	    if (mission == MI_SINTERDICT)
 		continue;
 
@@ -440,42 +437,30 @@ perform_mission(coord x, coord y, natid victim, struct emp_qelem *list,
 		(md > land_max_interdiction_range))
 		continue;
 
-	    if ((lp->lnd_ship != -1) || (lp->lnd_land != -1))
-		continue;
-
-	    if (lp->lnd_item[I_MILIT] < 1)
-		continue;
-
 	    range = roundrange(effrange(lp->lnd_frg, lp->lnd_tech));
 	    if (md > range)
 		continue;
 
-	    shell = lp->lnd_item[I_SHELL];
-	    gun = lp->lnd_item[I_GUN];
-	    if (shell == 0 || gun == 0)
+	    dam2 = lnd_fire(lp);
+	    putland(lp->lnd_uid, lp);
+	    if (dam2 < 0)
 		continue;
 
-	    if (has_supply(lp)) {
-		use_supply(lp);
-		putland(lp->lnd_uid, lp);
-		dam2 = ldround(landunitgun(lp->lnd_effic, lp->lnd_dam, gun,
-					   lp->lnd_ammo, shell), 1);
-		if (sect.sct_type == SCT_WATER) {
-		    if (chance(lp->lnd_acc / 100.0))
-			dam2 = ldround(dam2 / 2.0, 1);
-		}
-		dam += dam2;
-		if (sect.sct_type == SCT_WATER)
-		    nreport(lp->lnd_own, N_SHP_SHELL, victim, 1);
-		else
-		    nreport(lp->lnd_own, N_SCT_SHELL, victim, 1);
-		wu(0, lp->lnd_own,
-		   "%s fires at %s %s at %s\n",
-		   prland(lp), cname(victim), s, xyas(x, y, lp->lnd_own));
-
-		mpr(victim, "%s %s fires at you at %s\n",
-		    cname(lp->lnd_own), prland(lp), xyas(x, y, victim));
+	    if (sect.sct_type == SCT_WATER) {
+		if (chance(lp->lnd_acc / 100.0))
+		    dam2 = ldround(dam2 / 2.0, 1);
 	    }
+	    dam += dam2;
+	    if (sect.sct_type == SCT_WATER)
+		nreport(lp->lnd_own, N_SHP_SHELL, victim, 1);
+	    else
+		nreport(lp->lnd_own, N_SCT_SHELL, victim, 1);
+	    wu(0, lp->lnd_own,
+	       "%s fires at %s %s at %s\n",
+	       prland(lp), cname(victim), s, xyas(x, y, lp->lnd_own));
+
+	    mpr(victim, "%s %s fires at you at %s\n",
+		cname(lp->lnd_own), prland(lp), xyas(x, y, victim));
 	} else if (glp->thing->ef_type == EF_SHIP) {
 	    sp = (struct shpstr *)glp->thing;
 	    mcp = glp->cp;