plastic ar-15 upper ?

[dwwhite]

Does anyone have any experience with a plastic AR-15 upper reciever as can be found here:

http://www.gunbroker.com/Auction/ViewItem.asp?Item=76419056

I am starting the process of building an AR-15 and would like to do it as light as possible (more of an academic excercise at this point -- i.e. just how light can I go) but I don't want to do it at the expense of strength or safety.

I feel comfortable using a Cav Arms all plastic lower, but the upper scares me just a little. However, as far as I can tell, this is similar to the upper used by Professional Ordnance/Bushmaster on the Carbon-15. Is this correct, or am I just misguided?

I assume that a plastic upper/lower will give up some rigidity and accuracy, but that is not a huge concern for me right now, mostly I want to know about safety and functionality.

Thanks in advance for the advice,
David

 

[Shear_stress]

Vulcan arms doesn't have a great reputation. Also, unless there are metal inserts for the bearing surfaces and contact points, I'd expect this upper to wear pretty quickly.

Something else to consider. On a flattop, unless you plan on using a BUIS, the weight of the optics may pretty much negate the weight savings of eliminating the carry handle. If light weight is what you're after, you're probably better off with a used Colt "slickside" upper. Here's one for sale:

http://www.ar15.com/forums/topic.html?b=7&f=119&t=456232

 

[Mot45acp]

Bushmaster?