Firearms having a locked breech are disclosed. An example firearm includes a barrel; a bolt head; a firing pin having a bulge; a bolt head carrier having a forward position and a rearward position; a central force receiving component receiving a rear end of the barrel and defining a plurality of recesses;...http://www.google.com/patents/US7237469?utm_source=gb-gplus-sharePatent US7237469 - Firearms having a locked breech
