What is Back Boring (Oversized Bores)?

  Back boring is a technique of slightly enlarging the interior dimension of the bore of a shotgun beyond the normal dimensions. 

In the 12 gauge shotgun, the nominal SAAMI standard bore diameter is 0.729". 

  All SKB Competition Series 12 gauge over/under shotguns were produced with oversized bores. These barrels had a nominal bore diameter of 0.735". 

Instead of starting with a .729" bore and removing metal from the inside to create the larger diameter, SKB actually manufactured a .735" bore to begin with.

  • This maintains the barrel's strength. 
  • The oversized bores allow the wad to spread slightly reducing friction as it travels the length of the bore. 
  • The benefits are denser and more evenly distributed patterns; and a reduction in felt recoil.


Back to FAQ’s