I'm looking to build my first AR 15 and I'm still not 100% sure if everything I've chosen will work together and would love if anyone could give me their opinion if I've chosen parts that work together well and if they are good quality. I would love feedback on anything you guys think I should change. http://aeroprecisionusa.com/m16a4-lower-receiver.html http://ads.midwayusa.com/product/877204/dpms-complete-lower-receiver-parts-kit-ar-15?cm_mmc=pf_ci_connexity-_-Gunsmithing+-+AR-15+Parts+%28Not+Magazines%29-_-DPMS-_-877204 http://aeroprecisionusa.com/ar15-assembled-upper-receiver.html http://www.midwayusa.com/product/294654/dsa-receiver-extension-buffer-tube-assembly-6-position-mil-spec-diameter-ar-15-aluminum-black http://algdefense.com/quality-mil-spec-trigger-qms.html https://www.magpul.com/products/miad-gen-1-1-grip-kit-type-2 http://aeroprecisionusa.com/ar15-556-bolt-carrier-group.html http://aeroprecisionusa.com/556-14-5-m4-carbine-cmv-barrel.html http://aeroprecisionusa.com/ar15-enhanced-mlok-handguards.html https://www.magpul.com/products/afg-2 https://www.magpul.com/products/moe-carbine-stock-mil-spec https://www.magpul.com/products/pmag-30-ar-m4-gen-m3-window Also how long should I choose the hand guards for this current build. As you guys I'm sure can tell I'm really new to this and hope to make something fun I can go out with that works well too. Also I have no idea what a good sight/scope would be so I would really like some help there as well.