333 Buttstock Spacer: Some shooters use spacers to adjust the length of pull (LOP) on the rifle's stock. These spacers are inserted between the buttstock and the receiver to customize the length for the shooter's comfort. Barrel Spacer: In some cases, a spacer may be used to adjust the barrel tension on a Ruger 10/22. Barrel spacers can be added or removed to fine-tune the rifle's accuracy. Aftermarket Accessories: There are various aftermarket accessories and modifications available for the Ruger 10/22. These may include spacer-like components designed for specific purposes, such as improving accuracy, modifying the stock, or enhancing overall performance. Magazine Spacer: Some aftermarket modifications for the Ruger 10/22 involve using spacers in the magazine well to alter the feeding angle or improve the reliability of certain magazines. Rail or Optics Spacer: Shooters may use spacers to achieve the desired height or alignment when mounting optics, scopes, or other accessories on a Picatinny or Weaver rail attached to the 10/22.