diff --git a/include/prototypes.h b/include/prototypes.h
index 1ce9be30..b0788801 100644
--- a/include/prototypes.h
+++ b/include/prototypes.h
@@ -461,7 +461,6 @@ extern int lnd_prewrite(int, void *);
 extern double seagun(int, int);
 extern double fortgun(int, int);
 extern double landunitgun(int, int);
-extern double effrange(int, double);
 extern double torprange(struct shpstr *);
 extern double fortrange(struct sctstr *);
 extern int roundrange(double);
diff --git a/src/lib/subs/landgun.c b/src/lib/subs/landgun.c
index 7f40dbe9..617da772 100644
--- a/src/lib/subs/landgun.c
+++ b/src/lib/subs/landgun.c
@@ -220,7 +220,7 @@ lnd_fire(struct lndstr *lp)
 /*
  * Return effective firing range for range factor RNG at tech TLEV.
  */
-double
+static double
 effrange(int rng, double tlev)
 {
     /* FIXME don't truncate TLEV */