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Ultralight but reliable: Where to shave the weight on an AR? Adjustable gas blocks now being considered. Login/Join 
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posted
Hey all-

I am looking to build a lightweight AR. I have decided on a 16" Faxon pencil barrel to avoid the hassle and expenses of a 14.5" + pin-and-weld. The juice didn't seem worth the squeeze.

Where else can I save weight? I was looking at a slick side upper to shave a few ounces. Are there light handguard setups I should consider?

What else?

I am not looking to go all F1-spec and pay $200 an ounce to shave weight with carbon-titanium-magnesium everything. Just lighter while still retaining some measure of function and reliability.

How do you lighten things up?

Bruce

This message has been edited. Last edited by: RNshooter,




"I cannot spare this man. He fights!"
-Abraham Lincoln

"At the core of liberalism is the spoiled child — miserable, as all spoiled children are, unsatisfied, demanding, ill-disciplined, despotic and useless. Liberalism is a philosophy of sniveling brats."
-PJ O'Rourke
“It is just as difficult and dangerous to try to free a people that wants to remain servile as it is to try to enslave a people that wants to remain free."
-Niccolo Machiavelli

 
Posts: 3414 | Location: NV | Registered: October 06, 2011Reply With QuoteReport This Post
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I kinda forget -- what is 'light' these days anyway?

Under 7 pounds?

I feel like the barrel profile is the biggest bang for buck in terms of overall weight.



=============================


Proverbs 27:17 - As iron sharpens iron, so one man sharpens another.
 
Posts: 7415 | Location: Florida | Registered: September 20, 2004Reply With QuoteReport This Post
Fighting the good fight
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BCM KMR and MCMR handguards are relatively lightweight. Or, if you don't need any attachment points, you can go even lighter with a free float tube.

You can save some on the stock too with something like a Mission First Minimalist stock.
 
Posts: 23302 | Location: Northwest Arkansas | Registered: January 06, 2008Reply With QuoteReport This Post
Go ahead punk, make my day
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Well optics is a place where ARs often get heavy. If you are going with a RDS, stick to Aimpoint Micros or whatever cheapie Chicom knockoff fits your budget.

Definitely get a light-weight forend, not a quad rail.
 
Posts: 43034 | Registered: July 12, 2008Reply With QuoteReport This Post
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I can't speak to the reliability of each, but there are quite a few options for low-mass bolt carriers which will reduce the over-all weight of your finished rifle.

example:
https://www.brownells.com/rifl...&utm_campaign=Itwine

I have a "lightweight" upper that is really just a normal upper with a pencil barrel. I never found it worthwhile to do go the extra miles for low mass carriers or trying to source a slick-side upper. This is particularly the case with these skeletonized carriers, which can require an adjustable gas block to avoid timing issues. Just depends on how much you're willing to invest to get where you're going.
 
Posts: 17655 | Registered: August 12, 2000Reply With QuoteReport This Post
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quote:
Originally posted by Sig209:
I kinda forget -- what is 'light' these days anyway?

Under 7 pounds?

I feel like the barrel profile is the biggest bang for buck in terms of overall weight.



=============================


I don't have a number in mind, just "light". It should feel light in the hand and when transitioning from one target to another. Rearward weight bias without putting a heavy stock on it. The pencil barrel should be key, definitely. Is a free-floating handguard usually lighter than a delta ring setup? Is free-floating more or less important when using such a whippy barrel?

What about muzzle devices? I am leaning away from any brakes (weight on the end of the barrel plus the downward push might make more barrel whip) and towards an A2-type flash suppressor. Correct thinking?

Bruce




"I cannot spare this man. He fights!"
-Abraham Lincoln

"At the core of liberalism is the spoiled child — miserable, as all spoiled children are, unsatisfied, demanding, ill-disciplined, despotic and useless. Liberalism is a philosophy of sniveling brats."
-PJ O'Rourke
“It is just as difficult and dangerous to try to free a people that wants to remain servile as it is to try to enslave a people that wants to remain free."
-Niccolo Machiavelli

 
Posts: 3414 | Location: NV | Registered: October 06, 2011Reply With QuoteReport This Post
Nullus Anxietas
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Heck, I wasn't even going for low weight when I built mine. Nonetheless: It came out to weigh +-5 lbs., unloaded, before I added the light or optic.

I built it to more-or-less mirror my S&W M&P 15-22. I have friends close their eyes, hold each rifle by the barrel, and guess which is the 15-22. They can't tell Smile

Other than a couple failures to fully cycle w/in the first dozen rounds or so, it hasn't missed a beat, since then, through somewhere in the vicinity of 600+ rounds with a variety of .223 and 5.56 ammo.




"America is at that awkward stage. It's too late to work within the system,,,, but too early to shoot the bastards." -- Claire Wolfe
The dominant media is no more "mainstream" than leftists are liberals.
 
Posts: 16107 | Location: S.E. Michigan | Registered: January 06, 2008Reply With QuoteReport This Post
Fighting the good fight
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quote:
Originally posted by RNshooter:
Is a free-floating handguard usually lighter than a delta ring setup?


A standard M4 carbine handguard, delta ring, barrel nut, and handguard cap together weigh 9.1 ounces.

There are options for free float Keymod/MLOK handguards in the 7 to 9 ounce range (including mounting hardware). Not a huge weight savings, but you end up with a longer handguard, greater mounting options, and less barrel interference for the same or a little less weight.

With a plain tube handguard, you can get down as low as 4 or 5 ounces, especially with some of the carbon fiber ones.
 
Posts: 23302 | Location: Northwest Arkansas | Registered: January 06, 2008Reply With QuoteReport This Post
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Ensigmatic: Cool. What did you use? Got a parts list?

Bruce




"I cannot spare this man. He fights!"
-Abraham Lincoln

"At the core of liberalism is the spoiled child — miserable, as all spoiled children are, unsatisfied, demanding, ill-disciplined, despotic and useless. Liberalism is a philosophy of sniveling brats."
-PJ O'Rourke
“It is just as difficult and dangerous to try to free a people that wants to remain servile as it is to try to enslave a people that wants to remain free."
-Niccolo Machiavelli

 
Posts: 3414 | Location: NV | Registered: October 06, 2011Reply With QuoteReport This Post
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Should look at the Daniel Defense V7LW upper.


________________________________
 
Posts: 7533 | Location: One step ahead of you | Registered: February 10, 2009Reply With QuoteReport This Post
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I need to weigh mine, but I went for light weight with my build.
BCM pencil profile bbs, 16" midlength, main part I specifically went for lightness.

Magpul MOE grip & handguards, generic stock.

I imagine it's a bit lighter than my lightweight Tikka 270, which weighs in at 8lbs.




The Enemy's gate is down.
 
Posts: 7103 | Location: Spring, TX | Registered: July 11, 2011Reply With QuoteReport This Post
Glorious SPAM!
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LW barrels, no forward assist, CAR type stocks will all lead to weight reduction. I am a huge fan of lightweight carbines.

This carbine weighs in at 5 lbs. 9 oz. Accurate and reliable.





My Colt 6720 with a Comp M3 and Larue mount weighs in at about 6 lbs. 12 oz (with MOE grip). I have since gone back to the ACOG so it is probably a few ounces heavier now.

 
Posts: 9163 | Registered: June 13, 2003Reply With QuoteReport This Post
Nullus Anxietas
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quote:
Originally posted by RNshooter:
Ensigmatic: Cool. What did you use? Got a parts list?

Here's the last version of my build spreadsheet: AR_Build_Costs-v17.html. Everything's in there, incl. tools, cleaning supplies, and even some of the ammo I bought for initial testing. (I've tested it with many more kinds, since.)

It's not entirely accurate. Just off the top of my head: I went with the steel MagPul BUIS and the Savvy Sniper sling. I've also since replaced the buffer with a slightly heavier Spike's ST-T2 Tungsten Heavy Buffer and added a Magpul B.A.D Lever. I also upgraded the stock and the EOTech's been replaced with a Holosun HS510C.

Many of the links are not good, any more. And the MI rail has since been discontinued. It was replaced with a newer design. (Which kind of annoys me. If I ever damage my handguard I'll have to have the flash hider pin drilled out to replace the barrel nut )

Sorry for the formatting. It was simply exported to HTML from my spreadsheet.




"America is at that awkward stage. It's too late to work within the system,,,, but too early to shoot the bastards." -- Claire Wolfe
The dominant media is no more "mainstream" than leftists are liberals.
 
Posts: 16107 | Location: S.E. Michigan | Registered: January 06, 2008Reply With QuoteReport This Post
We gonna get some
oojima in this house!
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Midwest Industries G3 ultra light hand guards.

A lot of hand guards are light but the barrel nuts are heavy. The MWI stuff is light.


-----------------------------------------------------------
TCB all the time...
 
Posts: 6247 | Location: Cantonment/Perdido Key, Florida | Registered: September 28, 2009Reply With QuoteReport This Post
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I've decided to go with the Sampson Evolution rail since it uses as standard barrel nut and deletes the delta ring. Ounces saved without doing anything exotic.

Bruce




"I cannot spare this man. He fights!"
-Abraham Lincoln

"At the core of liberalism is the spoiled child — miserable, as all spoiled children are, unsatisfied, demanding, ill-disciplined, despotic and useless. Liberalism is a philosophy of sniveling brats."
-PJ O'Rourke
“It is just as difficult and dangerous to try to free a people that wants to remain servile as it is to try to enslave a people that wants to remain free."
-Niccolo Machiavelli

 
Posts: 3414 | Location: NV | Registered: October 06, 2011Reply With QuoteReport This Post
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How light and to be used for what. My wife needs really light for range only duty so I have built a few.
Not in any order of weight but barrel profile is critical, no muzzle device, no front sight (or backup rear), slabslide, different upper and lower material (have tried several), carbon free float tube, stock choice have been the things I've played with. Have always run an aimpoint micro and considered that mandatory.


“So in war, the way is to avoid what is strong, and strike at what is weak.”
 
Posts: 7843 | Registered: October 14, 2004Reply With QuoteReport This Post
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You already keyed in on the #1 place to save weight and got the lightest 16" barrel I'm aware of. I did a lightweight build with that same barrel.

Next places to look are hand guard, stock, receivers, gas block, muzzle device. Big weight savings to be had with a low mass carrier and a buffer with all the weights pulled out, but then you need an adjustable gas block and reliability could be an issue.

Mine came in at under 6lbs with a Primary Arms RDS and loaded 20rd magazine. I did use a low mass carrier and adjustable block, MFT stock, buffer with all the weights pulled out and an upper w/o port door or FA. I used a 10" ALG Mlok rail, I think it was in the 8oz range including all hardware which isn't bad for a 10" budget rail. Standard lower though, already had it and only a few titanium parts like grip screw and lock/castle nut and end plate, they weren't that expensive.

I was going for a blend of light but not crazy-light, crazy expensive. I think I put $800-$900 into that build.




“People have to really suffer before they can risk doing what they love.” –Chuck Palahnuik

The world's a dangerous place, we can help! http://portlandfirearmtraining.com/
 
Posts: 4500 | Location: Oregon | Registered: October 02, 2005Reply With QuoteReport This Post
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This will be a range toy and an exercise in simplicity.

I will pass on lightweight BCG's and buffers. I still want it to be lead-pipe reliable. I don't want a lightweight club, range toy or not.
I will probably go with a Sig Romeo or Fastfire III with no irons. A shorter rail would be a tad lighter but I like long rails. I will probably stick with the A2 flash hider but might consider a thread protector. We shall see.

Bruce




"I cannot spare this man. He fights!"
-Abraham Lincoln

"At the core of liberalism is the spoiled child — miserable, as all spoiled children are, unsatisfied, demanding, ill-disciplined, despotic and useless. Liberalism is a philosophy of sniveling brats."
-PJ O'Rourke
“It is just as difficult and dangerous to try to free a people that wants to remain servile as it is to try to enslave a people that wants to remain free."
-Niccolo Machiavelli

 
Posts: 3414 | Location: NV | Registered: October 06, 2011Reply With QuoteReport This Post
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My two match rifles have lightweight carries, adjustable gas and lightened buffers... if anything I'd say they're more reliable than my stock setups, with many times more rounds through them.


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Sliced bread, the greatest thing since the 1911.

 
Posts: 16933 | Location: 18th & Fairfax  | Registered: May 17, 2003Reply With QuoteReport This Post
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Cas-
I'm sure they are reliable, after your knowledgeable tweaking and adjusting. I don't know enough about adjustable gas blocks to be comfortable selecting one and tuning it.
Maybe I need to learn more about them.

Bruce




"I cannot spare this man. He fights!"
-Abraham Lincoln

"At the core of liberalism is the spoiled child — miserable, as all spoiled children are, unsatisfied, demanding, ill-disciplined, despotic and useless. Liberalism is a philosophy of sniveling brats."
-PJ O'Rourke
“It is just as difficult and dangerous to try to free a people that wants to remain servile as it is to try to enslave a people that wants to remain free."
-Niccolo Machiavelli

 
Posts: 3414 | Location: NV | Registered: October 06, 2011Reply With QuoteReport This Post
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