I too had the same problem even with a nylon prop and had attributed it to the plastic backplate on the spinner. I launched the spinner, went to a conical prop nut (DuBro-like), turned the rubber-dealie on the end of my starter around as appropriate, and have had absolutely no problems since.

I have been using a 10 x 6 Master Airscrew on my Avistar (on a TT .46 Pro) and am going to try out an APC prop for the heck of it. I am also going to try out other sizes, too, over time, such as 10 X 7, 11 x 5, etc.

BTW, cool trick I discovered when balancing my MAS props, instead of sanding down one end to balance, paint a nice, white visibility stripe at the last 1/2" on each side of each end (I use good ol' Testors model paint). Adding an extra few strokes on the light side will create enough weight to balance it out (really works!) and create a nice safety feature. You can see the end of the spinning black prop that is otherwise almost invisible.

[8D]

Cheers!

Jim