Re: Troy Alpha Rail
In my humble opinion the Troy Alpha rails are a very significant improvement compared to the TRX extreme rails. I ran a 13" TRX (VTAC flavor) and it was nice and light but had some flex. The Alpha (again VTAC flavor) rails I'm using now are more solid and the mounting system is very slick. I've got two 11" and a 13" railed uppers and they are very nice.
Serveral mounting hints...
1) Use blue locktite on the three screws that mount to the barrel nut.
2) When mounting the rail it looks like you have to have the barrel nut lined up perfectly. You don't! Just jam the rail all the way down until it meets the reciever. It took more force than I expected. Once you've got it fully mounted, the rail will turn on the barrel nut.
My current favorite rail.
Jake