They didn't in my D3, so i had a reaming party, and made it a mm or so bigger. But!
Made the tunnel just ever so slightly bigger then the 18500's. Put 'em in...
Nothing! So...went down to the hardware store and found me the " box of springs", got one that twists onto the stock spring without removing the old one, and presto! Guilt free lumens! Easy with the boring or you will have daylight coming through where the 0-rings are in no time! Check out the 3 bladed adjustible reamers at Mcmaster and Carr, maybe.