I appreciate all the positive feed back, I do my best to make sure its worth coming here! As far as a commercial or milspec tube, they are just different diameters. I am not sure the whole story on why they are out there, but to my knowledge none of the guns I sell come with that size. Unless someone needs one specifically, I dont really buy anything for them because they are not very common. Magpul does make Commercial sized stuff too tho. My magpul stuff is certainly cheaper than anywhere I've seen it in stock. Like Vances, or Blackwing. I was actually lower than they were at Knob Creek too which shocked me, that place is HUGE. I stock as much of their product line as I can, it just sells pretty fast.