It's probably about time to throw up a build thread. If you haven't guessed yet by the title, I'm going for a lightweight build on a budget. Something around 6lbs (minus optic) for around $600 would be ideal. The purpose will be mainly a walking varmint rifle, to replace my heavy-barrel Savage bolt gun. I'd like it to be at least somewhat accurate, worth taking to the range and maybe working up a load for.

A couple weeks ago I had no intentions of building an AR. I had shot them before, but the buffer spring twaaangg always bothered me. But I got talking to a friend about 80% lowers and one thing led to another, and now here I sit, waiting for the last few parts to arrive. Sorry, no pictures yet, but here's a parts breakdown:

Tactical Machining 80% lower - $50
Bushmaster stripped upper - $50
Black Hole Weaponry 16" .223 Wylde light profile stainless barrel - $110 (Gunbroker find)
Skull Tactical 13.5" slim keymod handguard - $90
Aim Surplus black nitride BCG - $100
Mil-spec charging handle, forward assist, dust cover - $40
Mil-spec buffer tube assembly - $30
Rousch low profile gas block and tube - $20
PSA Ptac lower parts kit with Magpul MOE grip - $45
Mission First Tactical Battlelink Minimalist stock - $45
A2 flash hider - $10
JP lightweight trigger springs - $10
IWC keymod bipod post - $20

So the total as it stands is about $620. I could easily lose the bipod nub to get to an even $600, but I'm omitting shipping on a couple of things, so I'll leave it. I'm hoping with the light (not pencil) profile barrel, free-float handguard, and lightweight stock it will come in somewhere in the sub 7lb range. I don't want to commit to an optic for it yet, but I'm leaning towards the Vortex 1.75-5 scope. I want to shoot it first to see if it deserves good glass or not. My Savage can hold sub 1" groups at 200yds with handloads pretty easily, but I'm hoping for around twice that.

I plan to work the GI trigger to see if I can get it to my liking before I start looking into a spendy trigger. I'm thinking I may have made a mistake buying the Ptac LPK. I've already tapped the lower for some set screws to adjust the trigger. Machining the lower is done already as well. I was nervous to buy the Skull Tactical handguard, but it looked like a knockoff of the Noveske NSR, for about 1/3rd the price, so I took a gamble. It arrived fast, and from what I can tell appears to be pretty well made. The machining and finish leave a little to be desired, but not much. Time will tell how it holds up.

Speaking of time, let's get the rest of the parts here already...

Sounds like a good build.  You got a heck of a deal on the barrel.  I am looking at the same one for my build.  I have only heard great things about them. Post some pics when you get a chance.

If you don't already have the upper receiver in hand, you could go with an Anderson sporter upper...it has no forward assist or ejection port cover which will save a couple more ounces.

I do already have the upper in hand. I wish I had known about the Anderson ones, though. It's too late to change, as I've already had to fit my upper to my lower slightly, due to my machining skills being a little lacking. I've seen delrin plugs for the forward assist holes, so maybe I'll do that in the future if everything runs reliably. I'm not going for ultralight, though, so an ounce or two here and there isn't a big deal.

As for the BHW barrel, there is another one on gunbroker right now, same seller.

I'll post pics when I have more to show.

Okay, I think I have everything I need to start building. Buffer tube and lower parts kit showed up today, so I was able to loosely thread everything together to give you guys an idea of how it's going to look. It's turning out pretty much how I was hoping.

Even though it's far from complete, I threw the BCG and an empty mag in my pocket, and if the bathroom scale can be believed I'm right at 6lbs. When you include the buffer and spring, and the rest of the small parts, I should still be sub 7lbs. I do wish I had known about the Anderson upper sooner, since not only would it have saved a little weight, but I would have saved a little green by building with it instead.

I am working on the same sort of build.  I am missing the barrel and really looking at BHW chambered in 223 Wylde.  I did end up with the Anderson upper and really like the minimalistic look.  

Have you seen this butt stock?  Talk about light!

http://www.ar15news.com/2015/02/05/coming-battle-arms-development-lightweight-buttstock/

I finished what I could of the upper and lower tonight. I don't have a spanner wrench for the buffer tube but, or a set of vise blocks to install the barrel, but that's about all that I have left to do. I went ahead and did a trigger job while I was building up the lower. The Ptac lower parts kit was pretty good -- better than I had expected. The only problems I had building things up were a slightly sticky forward assist, and an ejection cover that didn't want to stay closed. Both were easy fixes.

Will be getting on of these for sure...  Not sure why no one has thought of this before.  Simple idea.

That butt stock doesn't really interest me. Maybe if it extended the buffer tube to add some length of pull, but if your "stock" is going to be that short why even bother having a stock at all? I don't think you could scope a rifle with that stock without hanging the scope way out over the handguard to get enough eye relief. It would maybe work with open sights, but I want a scope, since that's what I'm used to shooting.

Thanks for the heads up!  Just won one from him.  Can't wait to see how it preforms.  I have only heard great things about them.  

Assembly complete. I'll get pics up soon. Looking forward to getting it to the range soon as well.

I need an optic. Any suggestions? I want something I can use for killing paper circles and the occasional varmint. Preferably smaller, somewhat tactical looking scope. I don't need a lot of magnification. Right now the scope at the top of my list is the Vortex Diamondback 1.75-5x32. Are there any similar scopes that also have parallax adjustment yet don't cost an arm and a leg?

Here's a picture of the completed rifle. You have to imagine it with a scope, since I don't have one for it yet.



So...now that you guys can see what I've built, tell me what I've built. Is this a recce? An SPR? Some sort of Mk-something? Does what I've built even fit into an existing category of AR? All I know is that I built what I wanted -- something light, accurate (hopefully), easy to handle, decently fun to shoot, at home either offhand or on a bench, cheap (but doesn't look it),...and untraceable. How'd I do?

Nice, I'm slowly putting together a lower cost LW build, so far I have an Anderson lower for $39.95, just ordered the Anderson sport upper for $39.95 and an ALG 10" M Lok rail for $85.  I really like the looks of the MFT Minimalist stock especially seeing it on a complete build, I'll likely go with that.

Depending on the barrel you'll probably end up a bit lighter than mine. I wasn't going for superlight, I just didn't want to add any unnecessary bulk. And I wanted something comfortable to shoot, hence the smaller diameter FF handguard. I think the Minimalist is a great stock, but then I don't have a lot of experience with other stocks.

I'm looking at doing a lightweight build for my wife, but I haven't really researched it much yet. Where did most of your weight savings come from? Stock and handguards?

Stock and handguards are a big part of it. Not having a bunch of unnecessary stuff attached is a big part of keeping it light. Barrel is probably the easiest place to save weight, but it's also probably the biggest factor in overall accuracy, so choose carefully. You can save a few ounces/grams here and there by paying attention to which upper, grip, bolt carrier, gas block, etc. you choose. Which sights/optic you choose makes a big difference as well. Remember, weight near the muzzle feels a lot heavier than weight near the buttstock.

If I were really going for weight, and keeping to a tight budget i.e. not just buying a bunch of skeletonized or titanium parts, I'd probably stick with the Minimalist stock, go to a 14.5" barrel with a pinned/welded flash hider or lose the flash hider and just get a thread protector instead, use a smooth-side upper, and maybe get a shorter handguard. No slings, bipods, flashlights, back up sights, extra rail sections, etc. If you're really concerned about weight and don't plan to be too hard on the rifle, consider a poly lower instead of aluminum.

I broke down and ordered a Weaver SPR 1" scope mount and Vortex Diamondback HP 2-8x32 scope for $270 shipped. I got tired of looking my build without being able to shoot it. I'll update again with pictures soon. Hopefully the mods will allow me to post pictures (instead of just links) to make this thread more interesting.

Scope arrived but the mount was backordered, so I cancelled it. I need to figure out the eye relief and how low I can get away with mounting the scope while still being able to see through it. Holding it in place it looks like I might be able to get away with just using rings instead of a cantilevered mount, but I want to mock it up better and take some measurements before I buy anything. I guess in that way it was good that the scope base was backordered. Looking forward to taking it to the range and getting it on paper.

Your build looks great!!!! I just finished one.

I mocked everything up to mount the scope using bits of wood and rubber bands to figure out the height and eye relief I would need. It looks like I can just get away with using rings if I want (I don't need a cantilevered base), but to be safe I think I want to at lease go with an extension ring up front. Does anybody know of any reasonably priced, decent quality extension rings with a saddle height of .75" +/- .1"? I've found the Weaver see-thru 49510 rings that seem perfect, but I'm not fond of the look. Do you guys know of anything more tacti-cool? Scope has a 1" tube.

Well, I finally got to shoot it the other day. I took my 12 year old twin girls to help me sight in the scope. I was worried that the Weaver see-thru rings would look stupid (like they do on most hunting rifles) but I was pleasantly surprised that they pretty much just blend in and look normal. They put the scope in perfect alignment with my eye using the MFT stock, plus they keep the scope about .25" closer to the barrel, which is better for shooting small targets at closer range. Sighting in took a while to get on paper, mostly because I kept relying on my girls ability to tell me if I was high, low, left or right. But once I did I was able to get some groups at about .75" from 60 yards. Not quite what I was hoping, but these were handloads I had done for a different rifle and I had to single load each one because the OAL was too long for the magazine. Plus I wasn't really trying for accuracy. I'll seat the bullets a little deeper in so that they fit and go try again in the next week or so I hope.

misterpepper how did handguard attach to the barrel nut ?

Six torx bolts, probably uses a very similar barrel nut like the Noveske NSR