Hello everyone this is my first post here, I tried several searches for lightest weight parts etc but didnt get many results and im looking to get a little help, as my back ground I have been shooting since I was young I did a brief 2yrs in the military i have worked in law enforcement and have shot competition but only as a novice, I own 5 ARs. Here is my situation and why i need some of your guys experience. Ok so I bought 2 Hybrid lowers They were advertised as aluminum lowers and i bought them in like a package deal, i honestly didnt even open the box on them as to me they were free. Upon inspection these turn out to be american tactical omni hybrid lowers, the magwells appear to be out of spec, but anyway im stuck with these lowers, and to be honest im the type of guy who doesnt want to sell them like this to someone else.
So I want to build an AR pistol the lightest weight i can with quality parts, as i figure i can switch everything over to a better lower at a later date if need be, and my buddy assures me he can make up some of that .003 difference with cerakote both on mags and gun, But we will see if that works down the road. But anyway I want to build a 10.5" pistol with QUALITY parts, $$$ is not an issue but basically being the lightest weight in class and still have quality and have been proven have a rep. etc. but being light weight is priority over everything but i still dont want a amazon chinese hand guard more like troy bcm yhm type quality and the lightest in class.
Im starting from the ground up with this lower please give me your parts lists so i can research them and please throw in why you like them.

here are a few links that should help out.

http://www.ar15.com/forums/t_3_118/625051_ULTRA_light_weight_picture_thread____the_under_6_crowd_.html

http://www.battlearmsdevelopment.com/products/lightweight

http://www.v7weaponsystems.com/

WOW, thank you this is what i needed, i never even heard of v7 before, and the picture thread, even though its mostly rifles, it helps me a ton! Thank you so much! If I can build this pistol with a weight around 4lbs I will be very very happy but im hoping to shot in the under 4lb range.

Well, not a 10.5" but here is a good start at 7.5"........

2A Armament Balios-Lite receiver set and gas block come in at 13.05 oz
Lower = 6.5 oz
Upper = 5.85 oz
Gas block = 0.7 oz
Add their 7” Rail with Titanium nut and hardware = 5.65 oz and a VooDoo Innovations 7.5" barrel at 12.96 oz

Total weight 2.02 lbs prior to Buffer&Tube, LPK, MD, BCG and of course optic.

Lightweight AR? V7, 2A Arms, JP, Boomfab, Rubber City Armory, Ballistic Advantage, Battle Arms Development, BCM KMR, etc etc..

Also check out: http://www.ar15.com/forums/t_3_118/638524_Lightweight_Parts_List_with_WEIGHTS__AR_15_.html

AWESOME! Thank you all so much this really helps me out a ton. I have goten a good list going now of parts I want and hopefully will have this build done by the end of may :)

Don't discount MAG Tactical. You can get stripped uppers and lowers made out of magnesium alloy. I have one of their lowers on a very simply 10.5" build (the upper is by DSG and has a Seekins lightweight KMR rail). I've been very happy with it.