Hi all. Am interested in a 9mm build and have been searching the board for info, as well as the Archive. Unfortunately have not run across the info I was looking for (my search fu must be weak). Like the Ace pistol ext. tube but there is another that has appeared with some frequency in the photos of builds. It appears to be much shorter than the Ace and has what appears to be a screw-on cap on the end of extension tube. Anyone know the make? How does it compare to the Ace as far as functionality? Other worthy options?
One more question- who has the shortened bolt carriers? Checked Bushmaster but didn't run across it. TIA.






EDITED for poor spelling, paragraph structure and various other sundries.