Just Kidding In this post we'll discuss the Mossberg forend tube. There are different names for the part - action tube, pump, slide. Unfortunately there are different styles of this part which causes much confusion. We'll go over the different versions and at the end post the famous chart. There are three distinct forend tubes. Any tube will fit any gun within its respective gauge. We will state what each gun typically comes with, but in reality this is subject to change. 7 5/8 'Long' forend tube. This is the original tube. Early ones were rattle traps, dimples and springs were added later. Most factory & aftermarket forends fit this length. Typically found on early guns and new security models. Total weight with forend is 11.5 ounces. 6 3/4 'Short' forend tube. These originally came out on sporting models. The 14 SBS requires this forend due to its short magazine tube. Also weighs 11.5 ounces. One-piece Polymer Forend. These have steel action bars pinned to a solid polymer forend. There are two types. The ribbed version is sturdy, lightweight forend that will not scratch the magazine tube like the steel forends. It is a good choice. The checkered forend is well known to break and not recommended. Weigh 7.5 ounces.