Boreguides

 Spudy says..."Using a Bore guide will save dragging all the debris from the barrel into your trigger group. They are designed to bridge the trigger and help keep debris and solvents from entering it. Rifles by Sako and Tikka can be problematic to find one that fits properly, but we would always recommend a universal one as the best option. The two-piece Sinclair type is really useful as the outer guide has an inbuilt solvent port to help wet the patch."

See here for a quick film on bore guides