Anyone have any experience building a super lightweight? I have seen polymer parts for almost everything and barrels that look like they are about as light as possible. If you have used any of these components I would appreciate your comments. Thanks for any input.

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Hue 68 noli me tangere

A Sport weighs in at about 6 1/2 lbs, if I remember correctly. How much lighter are you trying to go?

I've built a few AR's and also use the New Frontier Armory polymer lower.

I really liked the NFA polymer lower, hard to beat for the price ~110 for complete lower from joebob's.

I'd be curious what the weight of a completed rifle would be using that lower and an upper I recently built using the FAXON Pencil Profile 4150 CMV QPQ mid length barrel. That barrel is just over 1 lb. (I believe 1.145lbs) and has proven to be one of my most consistent and accurate barrels.

I've only sold one gun in my life and it happened to be that rifle I put together with the NFA lower and a DPMS pencil profile upper. That setup was good shooting, never had a single issue with it and it was the rifle that I loaned out to anyone who would come out to my place to target shoot. Had a guy offer me a hundred bucks more for it than I had in it, so I sold it, kinda wish I hadn't. It also happened to be about two weeks prior to the big black evil rifle scare when prices shot up sky high.....

As for lightweight rails, I like my MI Gen 2 SS rails and also the UTG Pro lightweight keymod rail. The UTG product is USA made and has one of the best barrelnut/hand guard locking setups I've ever seen. Both really slim profile

IIRC that NFA lower/DPMS pencil upper plus a red dot was right at 5.5 lbs.

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Rod
M&P 22A, 40c, 15A, 15-22

Haven't built one; have read a lot about doing it. Consensus among serious M4 shooters is that your money goes farthest with a lightweight barrel and rail; secondarily a minimal buttstock, perhaps.

Otherwise, shaved parts and exotic metals/materials exponentially increase price for very little practical weight loss.

As light as possible and still maintain reliability and durability but I don't need it to stand up to bayonet/buttstroke military drills. I just think most current AR rifles tend to be rather porky compared my A1 clone.

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Hue 68 noli me tangere

My AR in this configuration weighs only 5.94 lbs. Only thing I changed was the barrel, compensator, handguard, and FSB.

I don't know why folks worry about being able to buttstroke a badguy when it's much simpler and quicker to poke him hard with the muzzle

I'm not into M4 type rifles,although spent some time carrying
m16a2. Seems to me it was 51/2 lbs, unloaded. Already a avid
gun nut before drafted, I was amazed at accuracy. Now with all
the"attachments" they are approaching M-14 weight.

The standard M4 carbine weighs 6.4 pounds empty, before any tacticool stuff gets hung on it. In comparison the M16A1 weighs 7.2 pounds empty, so the M4 is only about 3/4 pounds lighter than the 20" M16A1 due to the other weight gains it picked up.

However, if you go with a slick side upper (no forward assist) and a 16" pencil weight barrel, and either a plastic telestock or a fixed entry stock (shorter than the A1 or A2 stocks) you can make a 5.7 pound carbine without having to go with a composite upper or lower. In this case I used a pair of retro looking triangular carbine handguards to go with the fixed entry stock. Combined with the slickside upper, it gives it a mini M16A1 look.



As noted above, the most frequent way shooters screw up a light weight AR-15 is by hanging all kinds of tactical trash on it - rails, optics, lights, etc - quickly turning a fairly lightweight M4 or M4gery into a 9 pound carbine that is slow, poorly balanced and prone to snagging on any branch within reach.

If you're going to add weight, do it in a manner that actually aides the handling of the rifle, or meaningfully adds to it's capability. In addition to the rifle above, I also shot this one below extensively in tactical rifle competitions. This one is an XM177E2 clone, with the exception of a heavier A2 gas block and barrel profile in front of the block and a full 1" profile under the handguards. The extra weight gives it a superb swing on moving targets and just enough weight to aide stability in offhand shooting. And the extra metal allows for greater barrel stability and accuracy after 30 plus rounds rapid fire.



I'm old school, but I've never seen any advantage to a dot sight on a carbine that is used primarily at ranges of 200 yards or less on people sized targets, unless you're shooting in low light conditions.

I built a lightweight on a GWACs lower. I don't remember exactly what it weighed, but was well under 6lbs. MI Gen 2 SS handguards are by far my favorite, and a must for a lightweight build - unless you go carbon fiber. I used a 9mm A2 upper, so as to avoid the extra weight of a forward assist and shell deflector. An M4 profile stainless barrel and AAC shorty brake round out the package. I'm sure I could shave a few more ounces with some titanium bits here and there, but honestly it is plenty light.

"I'm old school, but I've never seen any advantage to a dot sight on a carbine that is used primarily at ranges of 200 yards or less on people sized targets, unless you're shooting in low light conditions."

I well remember the day when I picked up a new iron-sighted Shorty, and the front sight, target, and everything else in view was FUZZY...Fortunately modern optics saved me. I've even used the minimalist Bushnell TRS-25 1X with 3MOA red dot, and it works pretty well at 200. Heck, the military gives stuff like this out to 20 year old troopers with perfect eyesight, so there's some point to them.

BTW, I agree with your "less is more" approach. That little Mini-16A1 is a cutie. Maybe I ought to build one up.

A .5 diopter lens works wonders for middle age accommodation issues. Both my NM Garand and my NM AR-15 have one installed in the rear sight hood.

In general though I still do quite well with aperture rear sights as the aperture effectively stops down light and improves your depth of field. A corrective lens is just icing on the cake.

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Way back in the day we were taught to snap shoot the M16A1 by looking down the carry handle with both eyes open. It functions like a gutter sight and for close range engagements you can shoulder and shoot it very fast with surprising accuracy. It wasn't a new concept as the same technique was used with the M14. Taping over the rear sight prevents any temptation to cheat and use the rear sight.

A dot sight achieves the same thing - but without the need for the same level of training - and it works well with rifles and carbines that might not point well naturally. Given all the stuff that gets hung on an M4, it falls in that category.

My basic gripe is that way too many AR-15 shooters are trying to create a carbine that mimics a fully loaded M4, but with no regard for they'll actually use it. They want the cool factor and they think that having a "mil-spec" carbine with loads of "mil-spec" stuff on it will give them the ultimate in capability, when that's just not then case. The advantage of a rail is that it makes the M4 mission adaptable, which more often than not, means leaving the stuff off when you don't need it - a point the tacti-cool shooters miss.

Personally, I just enjoy taking a retro carbine with nothing added and out shooting the tacti-cool crowd.

Look at the keltec offerings if you want a lightweight 223/556 gun.
If you want it to be an AR, going the SBR route is worth a look, or an AR pistol.

Some good threads on this at the M4 specialty site; first one linked is epic, and you may want to read it backwards because the build evolved significantly over time. Other two are recent and discuss some of the current lightweight parts on the market...

Project Featherweight

Parts advice for lightweight AR

new lightweight build complete

They are faster than irons if you want to put rounds on target/center mass. Put the dot on target and shoot. It's not ment for precision shots.

I disagree. It's a matter of training and indoctrination, but at short range, a dot sight is at best no faster than a well designed set of iron sights.

It's at longer ranges in excess of 50 yards where the dot sight starts to come in to it's own, and then it's in terms of offering a higher degree of precision without having to align the sights.

Let's consider the Uzi for a minute. It's surprisingly accurate for a sub gun and with a dot sight mounted on it, it is capable of shooting 3 MOA groups at 100 yards semi-auto, at least until the barrel gets hot. Without the dot sight, you'll be doing well to stay on an 12" plate at 100 yards given the rather crude iron sights and the short sight radius.



However, at close range, it's hard to beat an iron sighted Uzi for speed.



Those great big front and rear sight ears, the cocking knob and very good pointing characteristics make it extremely fast when snap shooting center of mass at close ranges of 25 yards or less. You literally just raise the weapon to eye level and look over the weapon at the target naturally framing it with the front sight ears with both eyes open and put rounds center of mass. You're not down on the stock looking through the sights but rather you've got your head erect looking over the sights.



It's from 25-50 yards where it becomes a bit of a toss up. A tube style dot sight like this Ultradot interferes with the field of view a bit, but you once again raise the weapon into your line of sight and with both eyes open put the dot on the spot you want to bleed. It's marginally slower, with a slightly reduced field of view, but it is much more precise.

At ranges beyond 50 yards the dot is the clear winner as it offers more precision, at speed, than using iron sights.

I this case with the dot sight mounted above the regular sights, the head position is the same with or without a dot sight attached.

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Now...some folks choose a hybrid approach and want to use a low mounted reflex sight like the Burris Doctor. It's low profile, light weight and co-witnesses with the iron sights when the mount is screwed or spot welded to the top cover.

The advantage at close range is that you can still look over the top of the sights and with your head erect, frame the target between the tops of the front sight ears - i.e. you are not using the dot sight at all.

At longer ranges however (25 yards or more) you've got to get your head down to look through the dot sight - close to where you'd be with the iron sight, which is actually a little slower, particularly if you are transitioning from a close shot to a long one and back again.

Well I use rifles but that's exactly how it work. Just raise the, rifle and shoot. Think of that cocking handle as the red dot.