President Biden's Apparently Incorrect Claim That AR-15 Bullets Travel 5 Times Faster Than Others

Here's the exact quote: Do you realize the bullet out of an AR-15 travels five times as rapidly as a bullet shot out of any other gun …?

The muzzle velocity of an AR-15 (which is to say, the speed at which the bullet travels when it leaves the rifle) is about 3300 feet per second (here's an anti-AR-15 Washington Monthly article confirming that).

Other rifles have muzzle velocities in the same general range, 2500-4000 feet per second or so according to this list, or 2700-3150 in this list (PDF p. 45), though the velocity is also influenced in some measure by barrel length. If the AR-15 bullets are faster than most rifles (not "any other" rifles), they're only slightly faster.