I am a noob regarding builds. I am going to first build 2 nearly identical light-weight AR-15's for my wife and me. I have already purchased light weight barrels, triggers, and optics. I have lowers.
I will sacrifice a few ounces for durability. (Yes. I realize there are direct tradeoffs.)
A couple questions:
1. I need stocks that are (obviously) light weight, but have adjustable cheek weld risers. I would prefer to add a couple ounces for one that is very solid when installed. I had been looking at Magpul PRS lite's, but the LOP on them is a concern. My wife is short with a short LOP. I prefer the major elements of the build to be identical.
2. I would appreciate suggestions on other parts (upper receivers, etc.), again as solid as possible while still light.
Thank you in advance.
BC
Some random thoughts.
Sometimes being a noob, but wanting to learn, means recognizing your requirements may be wrong. You may have started to notice that most people do not use adjustable cheek risers on ARs, because the charging handle needs to occupy the same space. Instead, select an optic mount that is the height you need - there are a lot of different height mounts on the market, so if you can, try a few on other rifles at the range and figure out what you need. You can do a cheek riser with a few limited options, but you'll likely find that it's placed too far back to be comfortable, and/or limits you to only right hand shooting depending on the design.
Also, your definition of light weight might be different than other people's, especially if you're looking at any sort of Magpul PRS stock; how heavy do you want these rifles to be? 4 lb? 6-7 lb? Some people even think a 10 lb rifle is "light weight".
Something like the Smoke Composites stock is very light weight, with their lightest options being about the same or lighter than a standard carbine buffer tube; those are great options for a 4 lb rifle, when paired with a pencil barrel and other very light weight parts. If you use that without the additional cheek riser (which I personally don't care for) you may want to consider a lower optic mount than if you use a stock. A word of advice - get the shorter of the two LOP options from Smoke; I ended up with the longer one and it's my one regret with that particular rifle.
A reasonably light but somewhat more mainstream setup I use a lot is the Rogers Superstock - it's adjustable on a carbine buffer tube, but locks down way more solidly than Magpul's stocks. (The lock is adjustable too) It's also lighter than even the base model Magpul MOE stock, and has built in QD sling swivels. They can be had at various places online for $30-$50, and you'll need to buy a buffer tube separately of course, unlike the Smoke Composites stocks. The Superstock is a great option for 6-8 lb rifles.
Most decent forged upper receivers are light weight and strong (compared to billet). Personally I like BCM or B. King's Mod 0 uppers for the thermofit connection to the barrel extension, which is good for accuracy.
Handguards make a big difference if you're trying to build light weight. Obviously don't make them longer than necessary (longer is heavier of course), but beyond that definitely pay attention to listed weights. Not everything made with carbon fiber or specialty aluminum alloys will necessarily be the lightest. If you're looking for 6 lb rifles, a lot of decent choices in aluminum handguards will work. If you're wanting ~4 lb rifles though, your options are significantly more limited, and companies like VSeven and Smoke Composites are good places to start.
I built my own carbon fiber handguard for my latest ultralight, using thin carbon fiber tubing and an aluminum barrel nut modified in my lathe. The whole thing ended up around 2.5 oz IIRC; lighter than the barrel nuts for most handguards where the complete package often ends up in the 8-12 oz range.
As a couple others pointed out above, light weight bolt carriers and buffers are a significant part of an ultra light build too; a reduced mass operating system (with correctly tuned gas of course) helps a lot to keep an ultra light rifle on target during rapid fire. It's pretty easy to save around 4 oz compared to a common full-auto carrier setup, or even more if you want to.
