This refers to specific information regarding the propellant charge (Retumbo powder) used in cartridges for the .270 Winchester Short Magnum (WSM) rifle caliber. This data typically includes powder weight, bullet type and weight, case overall length, and expected performance metrics like muzzle velocity and pressure. An example would be a listing showing a specific weight of Retumbo powder paired with a 130-grain bullet, producing a given velocity.
Accurate and reliable information of this nature is crucial for safe and effective handloading of ammunition. Handloaders utilize this information to develop loads tailored to their specific rifles and desired performance characteristics, such as accuracy and trajectory. Historically, handloading allowed shooters to customize ammunition when factory options were limited or unavailable. Today, it continues to be a popular practice for precision shooting and hunting, allowing for fine-tuning of ammunition beyond standard factory offerings. Properly developed handloads can maximize accuracy and ballistic efficiency for a given rifle.