diff --git a/source/build/include/build.h b/source/build/include/build.h
index 88f6dc6bb..4e9d7abde 100644
--- a/source/build/include/build.h
+++ b/source/build/include/build.h
@@ -938,7 +938,14 @@ int32_t   videoSetRenderMode(int32_t renderer);
 void    renderSetRollAngle(float rolla);
 #endif
 
-double calcSinTableValue(double index);
+//
+// Calculates and returns a sintable[] value of the equivilent index (and supports fractional indexes also)
+//
+inline double calcSinTableValue(double index)
+{
+    return 16384. * sin(BANG2RAD * index);
+}
+
 
 //  pal: pass -1 to invalidate all palettes for the tile, or >=0 for a particular palette
 //  how: pass -1 to invalidate all instances of the tile in texture memory, or a bitfield
diff --git a/source/build/src/engine.cpp b/source/build/src/engine.cpp
index 3ae659ae4..bc73e5f27 100644
--- a/source/build/src/engine.cpp
+++ b/source/build/src/engine.cpp
@@ -4323,12 +4323,3 @@ void renderSetRollAngle(float rolla)
 }
 #endif
 
-//
-// Calculates and returns a sintable[] value of the equivilent index (and supports fractional indexes also)
-//
-double calcSinTableValue(double index)
-{
-    double value = fabs(16384. * sin(BANG2RAD * (index - (fmod(index, 512) * 2))));
-    return (index >= 1024 ? -value : value);
-}
-
diff --git a/source/games/duke/src/hudweapon_d.cpp b/source/games/duke/src/hudweapon_d.cpp
index 5db8c63e1..f99677c4f 100644
--- a/source/games/duke/src/hudweapon_d.cpp
+++ b/source/games/duke/src/hudweapon_d.cpp
@@ -305,11 +305,11 @@ void displayweapon_d(int snum, double smoothratio)
 	gun_pos = 80 - (opos + fmulscale16(npos - opos, smoothratio));
 
 	weapon_xoffset =  (160)-90;
-	weapon_xoffset -= calcSinTableValue(fmod((weapon_sway / 2.) + 512, 2048)) / (1024. + 512.);
+	weapon_xoffset -= calcSinTableValue((weapon_sway / 2.) + 512) / (1024. + 512.);
 	weapon_xoffset -= 58 + p->weapon_ang;
 	if( sprite[p->i].xrepeat < 32 )
-		gun_pos -= fabs(calcSinTableValue(fmod(weapon_sway * 4., 2048)) / 512.);
-	else gun_pos -= fabs(calcSinTableValue(fmod(weapon_sway / 2., 2048)) / 1024.);
+		gun_pos -= fabs(calcSinTableValue(weapon_sway * 4.) / 512.);
+	else gun_pos -= fabs(calcSinTableValue(weapon_sway / 2.) / 1024.);
 
 	gun_pos -= (p->hard_landing<<3);