RCBS Small Base 2-Die sets are useful for reloaders loading for semi-automatic, pump action and lever action rifles to help ensure that proper functioning. Small base sizing dies size brass to minimum specifications and help to ensure that cartridges will chamber every time. Due to the fact that this product sizes more than regular dies, it is crucial to have a sufficient amount of high quality lubricant to prevent stuck cases. Notes: Applies a roll crimp.Small base sizer dies are usually required for reloading ammunition to be used in automatic, semi-automatic, pump, slide and some lever-action rifles.These dies size the case somewhat smaller in diameter and also set the shoulder back slightly more than a Full-Length sizer die to ensure proper functioning in the actions of these rifles.NOT RECOMMENDED FOR AMMUNITION IN BOLT-ACTION RIFLES.Shellholder NOT included.