Muzzle velocity is NOT a constant! It varies considerable due to a host of factors. In order to successfully engage targets at long range it is CRUCIAL that you be able to predict account for your MVV (muzzle velocity variation). This is the entrance key into effectively setting your ballistics tables. Whether you will be using ballistic software in the field, ballistic cards, or using a calc form to come up with your firing solutions, this information is key to getting your ballistic data arranged in a way that will be effective across various bore conditions and multiple ammunition temperature ranges. Below is the link to the Ammo Temp MV Curve TABLES by TiborasaurusRex: https://docs.google.com/file/d/0Bzvx3RuRX1QTNzBkV3R2UE14WDA/edit?usp=sharing DOWNLOAD THE CURRENT VERSION by hitting the downward pointing arrow at the top left of the page and OPEN or SAVE the document so you can use it. Video DETAILED NOTES: Muzzle Velocity Variation (MVV) A. Bore/projectile Dynamics and MVV 1. Bore wear - Gas escaping around the projectile decreases chamber pressure and can lower MV 2. Fowling - An increase in bore resistance to projectile movement before peak pressure increases the pressure developed within the barrel and can cause MVV. 3. Coppering a) Slight coppering resulting from firing a small sample of rounds at higher charges tends to increase muzzle velocity. b) Erratic velocity performance is a result of excessive coppering whereby the resistance of the bore to projectile movement is affected. 4. Bore Temperature - Variations in bore resistance can be caused by temperature differences between the inner and outer surfaces of the barrel. 5. Projectile Temperature 6. Barrel Memory - Originally observed in field artillery -- According to the FM 6-40: Tube Memory is a physical phenomenon of the cannon tube tending to react to the firing stress in the same manner for each round, even after changing charges. It s