RE: AMR TRAINER 20
I agree with Ken, I have 1/4x20 nylon bolts on my 10lb Sr Telemaster and my 12 1/2 lb BUSA Pup with no problems. Sometimes old nylon bolts (and props) get brittle, it's probably a good idea to replace them every year or two when you change your fuel line. I had the head pop off of a older nylon bolt when the plane was just sitting in the pits.