The Universal Bore Guide offers an easier and safer clean by aiding in the alignment of your cleaning rod with the barrel of your firearm. Proper rod alignment prevents bowing and bending which can damage the bore. The built-in solvent port reduces the chance of spilling and wasting solvent, which could ruin the finish of your firearm. The Shooter's Choice Universal Bore Guide also includes a collar designed for MSR/AR style rifles, which creates a tighter fit and additional support of the upper receiver while cleaning your rifle. Fits most centerfire and bolt-action rifles.