Never used a bore guide in fifty plus years of cleaning centrefire and rimfire rifles. Another pointless gimmick like "bolt holsters" that solves a problem that doesn't exist. Remove bolt, insert rod carrying phosphor bronze brush, or wool mop, or jag from the breech end and clean, oil, dry out as required. Yes if you clean from the muzzle and over muzzle cap might be useful...think Winchester 94 rifles, Martini action rifles, etc. But otherwise save your money IMHO.