diff --git a/core/src/net/sf/openrocket/rocketcomponent/SymmetricComponent.java b/core/src/net/sf/openrocket/rocketcomponent/SymmetricComponent.java
index 9cd011ead..78d4f8260 100644
--- a/core/src/net/sf/openrocket/rocketcomponent/SymmetricComponent.java
+++ b/core/src/net/sf/openrocket/rocketcomponent/SymmetricComponent.java
@@ -281,14 +281,25 @@ public abstract class SymmetricComponent extends BodyComponent implements BoxBou
 	
 	
 	/**
-	 * Calculate CG of the component by integrating over the length of the component.
-	 * The method caches the result, so subsequent calls are instant.  Subclasses may
+	 * Return the CG and mass of the component.  Subclasses may
 	 * override this method for simple shapes and use this method as necessary.
 	 * 
 	 * @return  The CG+mass of the component.
 	 */
 	@Override
 	public Coordinate getComponentCG() {
+		return getSymmetricComponentCG();
+	}
+
+	/**
+	 * Calculate CG of the symmetric component by integrating over the length of the component.
+	 * The method caches the result, so subsequent calls are instant.  We need this method because subclasses
+	 * override getComponentCG() and include mass of shoulders
+	 * 
+	 * @return  The CG+mass of the component.
+	 */
+
+	private Coordinate getSymmetricComponentCG() {
 		if (cg == null)
 			integrate();
 		return cg;
@@ -491,7 +502,7 @@ public abstract class SymmetricComponent extends BodyComponent implements BoxBou
 		longitudinalInertia /= vol;
 		
 		// Shift longitudinal inertia to CG
-		longitudinalInertia = Math.max(longitudinalInertia - pow2(getComponentCG().x), 0);
+		longitudinalInertia = longitudinalInertia - pow2(getSymmetricComponentCG().x);
 	}
 	
 	
@@ -548,7 +559,7 @@ public abstract class SymmetricComponent extends BodyComponent implements BoxBou
 		rotationalInertia /= surface;
 		
 		// Shift longitudinal inertia to CG
-		longitudinalInertia = Math.max(longitudinalInertia - pow2(getComponentCG().x), 0);
+		longitudinalInertia = longitudinalInertia - pow2(getSymmetricComponentCG().x);
 	}
 	
 	
diff --git a/core/test/net/sf/openrocket/masscalc/MassCalculatorTest.java b/core/test/net/sf/openrocket/masscalc/MassCalculatorTest.java
index a790cfc07..a36109567 100644
--- a/core/test/net/sf/openrocket/masscalc/MassCalculatorTest.java
+++ b/core/test/net/sf/openrocket/masscalc/MassCalculatorTest.java
@@ -625,7 +625,7 @@ public class MassCalculatorTest extends BaseTestCase {
 			// Component: Nose Cone			
 			final NoseCone payloadNose = (NoseCone) payloadStage.getChild(0);
 			assertEquals(payloadNose.getName() + " Rotational MOI calculated incorrectly: ", 3.508155e-5, payloadNose.getRotationalInertia(), EPSILON);
-			assertEquals(payloadNose.getName() + " Longitudinal MOI calculated incorrectly: ", 2.0400578477e-6, payloadNose.getLongitudinalInertia(), EPSILON);
+			assertEquals(payloadNose.getName() + " Longitudinal MOI calculated incorrectly: ", 3.993059978352989E-5, payloadNose.getLongitudinalInertia(), EPSILON);
 
 			// Component: Payload BodyTube
 			final BodyTube payloadBody = (BodyTube) payloadStage.getChild(1);
@@ -695,7 +695,7 @@ public class MassCalculatorTest extends BaseTestCase {
 			expInertia = 1.73189409900e-5;
 			compInertia = boosterNose.getRotationalInertia();
 			assertEquals(boosterNose.getName() + " Rotational MOI calculated incorrectly: ", expInertia, compInertia, EPSILON);
-			expInertia = 4.51796586171e-6;
+			expInertia = 1.814234981813717E-5;
 			compInertia = boosterNose.getLongitudinalInertia();
 			assertEquals(boosterNose.getName() + " Longitudinal MOI calculated incorrectly: ", expInertia, compInertia, EPSILON);
 
@@ -946,7 +946,7 @@ public class MassCalculatorTest extends BaseTestCase {
 		double boosterMOIRotational = spent.getRotationalInertia();
 		assertEquals(" Booster x-axis MOI is incorrect: ", expMOIRotational, boosterMOIRotational, EPSILON);
 
-		double expMOI_tr = 0.0573781722;
+		double expMOI_tr = 0.057405421013859766;
 		double boosterMOI_tr = spent.getLongitudinalInertia();
 		assertEquals(" Booster transverse MOI is incorrect: ", expMOI_tr, boosterMOI_tr, EPSILON);
 	}
@@ -964,7 +964,7 @@ public class MassCalculatorTest extends BaseTestCase {
 
 		final double expIxx = 0.0122505987;
 		final double actIxx = launchData.getRotationalInertia();
-		final double expIyy = 0.0635943662;
+		final double expIyy = 0.06362161493172772;
 		final double actIyy = launchData.getLongitudinalInertia();
 
 		assertEquals(" Booster x-axis MOI is incorrect: ", expIxx, actIxx, EPSILON);
@@ -1010,7 +1010,7 @@ public class MassCalculatorTest extends BaseTestCase {
 		double boosterMOI_xx = burnout.getRotationalInertia();
 		assertEquals(" Booster x-axis MOI is incorrect: ", expMOI_axial, boosterMOI_xx, EPSILON);
 
-		double expMOI_tr =  17.78076176335;
+		double expMOI_tr =  17.78078901211703;
 		double boosterMOI_tr = burnout.getLongitudinalInertia();
 		assertEquals(" Booster transverse MOI is incorrect: ", expMOI_tr, boosterMOI_tr, EPSILON);
 	}
@@ -1064,7 +1064,7 @@ public class MassCalculatorTest extends BaseTestCase {
 		double boosterMOI_xx = boosterData.getRotationalInertia();
 		assertEquals(" Booster x-axis MOI is incorrect: ", expMOI_axial, boosterMOI_xx, EPSILON);
 
-		double expMOI_tr =  0.347611843243;
+		double expMOI_tr =  0.34852907557064894;
 		double boosterMOI_tr = boosterData.getLongitudinalInertia();
 		assertEquals(" Booster transverse MOI is incorrect: ", expMOI_tr, boosterMOI_tr, EPSILON);
 	}
@@ -1111,7 +1111,7 @@ public class MassCalculatorTest extends BaseTestCase {
 		double boosterMOI_xx = structure.getRotationalInertia();
 		assertEquals(" Booster x-axis MOI is incorrect: ", expMOI_axial, boosterMOI_xx, EPSILON);
 
-		final double expMOI_tr = 0.040598624476;
+		final double expMOI_tr = 0.04062587324372749;
 		double boosterMOI_tr = structure.getLongitudinalInertia();
 		assertEquals(" Booster transverse MOI is incorrect: ", expMOI_tr, boosterMOI_tr, EPSILON);
 	}