Excellent quality, easy to install.

I love the extension tube. Lets me get a total of 7 rounds in the mag with one in the chamber for allot of fun! I had no problem with installing this upgrade. My only critique of it, is that it sticks out beyond the muzzle a few inches. Therefore, it gets carbon scoring on the last 1 inch or so that has to be scrubbed off when cleaning. My solution (untested yet) was to buy a Carlson extended choke. I thing the little extra length may prevent it from happening or at least reduce it. Just something to be aware of.

not 4+ just hold 3+ total 8 in the tube with the spring that come and billet follower..

Great fit and finish matched the gun.

This product was easy to install and does as advertised. The extended magazine is 1.5 inches longer than the barrel, but it doesn't look too bad. If you want to even it out or make the barrel longer than the magazine, install an extended choke. That's what I did.

Great magazine extension and it matches the Marine. Easy to install. It does stick out a little past the barrel. I added a longer choke and it evens out. I love MAC, great firearms