Funny, I had just finished building....
This about an hour ago.
I have built quite a few. I don't know how to mount a swiss army knife on one though.
Question is what do you gents want to built. There are so many things to consider. Well I guess only three things.
Are the zombies fast or slow? Do you need to get them right tween the eyes or will any ol' head shot do?
Do you plan on engaging them in the country or city, or a bit of both?
Do you anticipate a shortage of fuel when the zombie attack breaks down society?
There are legit reasons for all those questions..
Do you want a long range heavy tack driver with big glass or a short range pop can slayer or something in between?
Now I would be happy to make recommendations on what you should buy if you provide what sort of firearm you wish to have when you are finished.
Of course bear in mind I have definite ideas and opinions and you may not like the hardware I prefer but I will be happy to make recommendations.
I will also help you build it once you get parts. I will even let you use my tools! My fee is 2 beers per hour or food, your choice.
I will give you a list of all the parts so you have a base of reference:
Lower receiver: You can save money here as they are all about the same and are less critical for function, accuracy, and reliability than the upper receiver.
Lower receiver parts kit: I like RRA but any will do.
They come with all lower parts and a standard AR pistol grip and trigger. You may want to consider a better trigger and pistol grip. We can do a trigger job on the standard trigger without to much extra trouble.
Buffer tube: there are carbine, rifle, entry, and pistol (don't get pistol!!!!) Carbine are the most common and they come in two flavors commercial and milspec. I recommend a mil spec carbine for just about any rifle unless you want an A2 stock or some fancy target stock.
Buffer: there are rifle buffers, H, H2, H3, H4 or XH, 9mm buffers (4 or so different weights) (not just for 9mm) and some super light weight buffers.... Going to have to decide on the rest of the gun and what you want to do with it before correct buffer choice can be made.
buffer spring:Unless you want to dig up a Tubbs or Wolff spring they are all about the same.
Butt stock: so many available. It would be best if you could try them all before picking but... standard carbine collapsible or A2 are going to be cheapest.
Barrel and barrel extension: good place to spend a little extra.
FSB or gas block: Usually the barrel you choose will come with a FSB or gas block and gas tube. The best barrels have pinned gas blocks, set screws suck.
Flash hider or muzzle break (muzzle device): name says it all.
Upper receiver: another good place to spend a little.
Fore stock: A2 plastic is cheapest, carbon lightest, rails versatile, monolithic rails really versatile and nice heat sinks.
Charging handle: unless you get a gas buster they are all the same.
Bolt: depends a bit on what barrel you buy, the best barrels have matched bolts so they come with one.
Bolt carrier: Semi, Full auto, match, match full auto, light weight, ohh getting tired of writing this list!
Sights: if you want iron sights... I usually don't bother.
Glass: woo perty....
Anyway if you have one of everything above it will go bang. I didn't bother with the really small stuff, it either comes in a lower parts kit or as part of a BCG so you don't need to buy them individually.