Ruger has issued a Product Safety Bulletin for certain Ruger Precision Rifles due to the potential for interference between the aluminum bolt shroud and the cocking piece (also known as the firing pin back). Although only a small percentage of rifles appear to be affected and we are not aware of any injuries, Ruger is firmly committed to safety and is offering replacement aluminum bolt shrouds for affected rifles in order to eliminate the possibility of such interference. View Safety Bulletin PDF
Or go to the website https://ruger.com/dataProcess/rprSafety/
where there is a short video.