This is L magazine tube Winchester model 1886 rifle. It is drilled through on the Forearm magazine plug screw. This tube is RIFLE that has a half-length magazine measuring 15 1/2 inches long. If you have the carbine and need a longer tube see part number mt86-C. Use magazine spring part number ms86 and follower wp721-a Tube measurements; OD is .720, ID is 634 (mag plug has NO LIP).