Hello from Michigan. I just purchased some 3 Gr/in weight tubes for my Beman 400 mfx's and was wondering if anyone has tips for installing them besides what the video on 3 Rivers shows.

They are pretty straightforward to install.  I measured the length of each arrow shaft by running the weight tube (uncut) down the shaft.  I then marked the end of the shaft with my thumb and subtracted the length of the nock insert from the lenght of the weight tube.  After I cut it to length, I used 3R's trick of crimping it every 6" or so to create extra friction so that it wouldn't move around.  The reason I measured each shaft vs. just measuring one shaft and then cutting all to length is due to the fact that there may be extra glue at the insert end that effectively shortens the interior shaft length.  I have found that it is very hard to remove the weight tubes from the shaft after you have cut them to length so I took the time to measure each shaft before I cut the weight tube.  Hope that helps.

Thanks a lot Glenn.

Only thing I had a problem with...be sure they fight snug on the length. If they are short, it will pop the nocks off when you hit something hard.