diff --git a/info/Options.t b/info/Options.t
index c5ec70f3..2c4efd8e 100644
--- a/info/Options.t
+++ b/info/Options.t
@@ -37,7 +37,7 @@ Allows real-time updating of mobility.
 .L NOFOOD
 No food is required.
 .L NOMOBCOST
-Ships pay 0 mob to fire. Subs pay 1/2 a sect's movement cost.
+Firing a ship's guns costs no mobility.
 .L NO_FORT_FIRE
 Forts cannot fire.
 .L NO_PLAGUE
diff --git a/info/fire.t b/info/fire.t
index e55a1982..7ad8a030 100644
--- a/info/fire.t
+++ b/info/fire.t
@@ -74,8 +74,7 @@ also hit subs using ASW planes or subs which have sub-torp capability.)
 The program then prints a satisfying \*QKaboom!!!\*U and,
 assuming you were in range, inflicts damage.
 .s1
-Ships lose mobility points equal to 1/2 the cost they would
-pay to move 1 sector for each shot fired. (If the NOMOBCOST
+Ships lose 15 mobility points for each shot fired. (If the NOMOBCOST
 option is in use, ships pay no mobility for firing.)
 .s1
 The damages inflicted vary with efficiency of the attacker,