I read a post about the Cortina Precision Bolt Shroud early this year so I decided to try one. After I bought one for the 20" Bergara I had to replace the bolt shroud on my 18" HMR as well. If there is an accuracy difference I can't tell, but I can say this reduces 95% of the play that the bolt has in the closed position. It comes with the shroud and a reduced power spring which may even make the bolt operation lighter and easier. Installation is ten minutes if you take your time and it just makes it feel so much better to open and close. I've had them on since early June without a single issue.