Building a lighter AR didn't work out so well...

[NeverEnoughFDE]

My goal was to be under 6 lbs with optic (PA 5x micro prism w/PA mini reflex red dot).
Without any accessories or optics (But with stock installed) it is 5.7 lbs

PA advertises the 5x & 3x micro prisms as weighin 8 oz. No way in hell.... (EDITut the optic setup on the scale & 1 lb!) I may as well just go back to an LPVO smh...After I added the optic setup listed above, the Centurion hand stop & rail covers & VTAC 2 pt sling, the weight shot up to 7.1 lbs!!!!

After I added the Surefire SOCOM MINI2 can, we are at 7.9 lbs.....
I know I can shave a few more ounces by going with the MFT stock, PSA BCG, lighter FH & a lighter buffer setup. However, I went with this FH because of the SOCOM MINI2 and the buffer setup because it will be suppressed full time.

Full parts list below.

Ruger stripped lower
B5 Type 23 grip
Geissele ambi safety
Stag LPK
V7 takedown pins, grip screw, ejection port cover & rod & end plate & castle nut
Centurion 14.5" lightweight hammer forged barrel
Magpul enhanced trigger guard
Toolcraft BCG
Warhammer CH
B5 Bravo stock
Centurion rail covers & hand stop
Odin works extended mag release
CMMG Zeroed bolt catch
Larue MBT-2S trigger
2A Armament upper receiver
2A builder series buffer tube
Midwest micro gas block
Centurion gas tube
Strike FA
Geissele Super 42 H2 buffer & spring
Midwest 12.6" Ultralight handguard
Surefire closed tine FH/suppressor adapter

 

[bfoosh006]

Pics... or it didn't happen... Lol

 

[Shawn Dodson]

That's heavier than my AR308, which weighs 7 1/4 lbs (minus optic)

 

[NeverEnoughFDE]

That's heavier than my AR308, which weighs 7 1/4 lbs (minus optic)

Now I feel even worse lol

Gotta be more ways to cut weight off this thing without making it unreliable

 

[LocoGringo]

Now I feel even worse lol

Gotta be more ways to cut weight off this thing without making it unreliable

Faxon lightweight bolt carrier group or Iron City Rifleworks lightweight BCG, Taccom reduced power recoil spring with plastic buffer, adjustable gas block (necessary...I like SLR Rifleworks)

 

[InTheSwamp]

That's heavier than my AR308, which weighs 7 1/4 lbs (minus optic)

Or just a tad lighter than a "Mil-Spec" AR-15, which works all the time.

 

[NeverEnoughFDE]

Faxon lightweight bolt carrier group or Iron City Rifleworks lightweight BCG, Taccom reduced power recoil spring with plastic buffer, adjustable gas block (necessary...I like SLR Rifleworks)

Again, running with a can so buffer system likely won't change./
Lightweight BCG is likely a no go as not dealing with adjustable gas block

 

[LocoGringo]

Again, running with a can so buffer system likely won't change./
Lightweight BCG is likely a no go as not dealing with adjustable gas block

Well, an adjustable gas block can also reduce gas exiting out of the ejection port and keep your rifle from beating itself to death. They're really simple and easy to tune, but whatever.

Good luck with your endeavor. I made my suggestions...

 

[Skylerbone]

You won’t ever shave 2 lbs off that rifle. You could swap out the upper and lower receivers for high dollar lite versions and save a few ounces, swap the bolt for said same and drop a few more. Use a truly minimalist stock, AGB, and find a shorter barrel and lighter can, swap that MI for a CF, but what does that really leave you with? I’d suggest checking balance and reducing forward weight. Live with that and be happy or build a whole ‘nother rifle.

One note to mention, and it often goes unchecked; handguard weight. Terms like LW or CF are eye catching when they discuss oz…until they omit barrel nut weight. 1/5th of my 15” guard of choice comes from the proprietary nut, but they do list the weight of each item separately. I was looking into a LW build for my daughter years ago and stumbled on a CF tube that was only 2 oz lighter, that, as it turned out was before the added weight of the nut made it heavier. Best $300 I never spent. Good luck on your lightening project.

 

[mavracer]

You really haven't done that bad as a lightweight build, but your goal was ultralight lol.
If you want ultralight you really need to start with a pencil profile barrel and don't add stuff you don't need to.
As for optics you're not really gonna lose much unless you lose the battery too most LPVOs with illumination are gonna be a pound or better by the time you add the mount.
I had a little different goal in mind when I went to build my LW AR (hunting carbine)
It's only a smidge lighter than yours at 7.5#
Including a mag as pictured. Most of the difference is probably barrel (mine has a bigger hole in it @.355) and the can is just 5.5 oz.

 

[NeverEnoughFDE]

Well, an adjustable gas block can also reduce gas exiting out of the ejection port and keep your rifle from beating itself to death. They're really simple and easy to tune, but whatever.

Good luck with your endeavor. I made my suggestions...

. No need to be rude

 

[NeverEnoughFDE]

You really haven't done that bad as a lightweight build, but your goal was ultralight lol.
If you want ultralight you really need to start with a pencil profile barrel and don't add stuff you don't need to.
As for optics you're not really gonna lose much unless you lose the battery too most LPVOs with illumination are gonna be a pound or better by the time you add the mount.
I had a little different goal in mind when I went to build my LW AR (hunting carbine)
It's only a smidge lighter than yours at 7.5#
Including a mag as pictured. Most of the difference is probably barrel (mine has a bigger hole in it @.355) and the can is just 5.5 oz.

Right, I have an LPVO on another rifle & went with this PA to save weight, but they advertise the weight without mount which is misleading. I ordered an ADM mount last night so let's see if that helps enough.

The goal was under 6 lbs with optic, not ultralight. I didn't go LW BCG etc because it needs to be 100% reliable.

 

[NeverEnoughFDE]

You won’t ever shave 2 lbs off that rifle. You could swap out the upper and lower receivers for high dollar lite versions and save a few ounces, swap the bolt for said same and drop a few more. Use a truly minimalist stock, AGB, and find a shorter barrel and lighter can, swap that MI for a CF, but what does that really leave you with? I’d suggest checking balance and reducing forward weight. Live with that and be happy or build a whole ‘nother rifle.

One note to mention, and it often goes unchecked; handguard weight. Terms like LW or CF are eye catching when they discuss oz…until they omit barrel nut weight. 1/5th of my 15” guard of choice comes from the proprietary nut, but they do list the weight of each item separately. I was looking into a LW build for my daughter years ago and stumbled on a CF tube that was only 2 oz lighter, that, as it turned out was before the added weight of the nut made it heavier. Best $300 I never spent. Good luck on your lightening project.

My MI handguard is only 8 oz total. & is 12.6"
Shorter barrel? Not building a pistol here. I'd imagine balance would be way off with the can on & the MFT stock, though.

 

[mavracer]

The goal was under 6 lbs with optic, not ultralight.

you can tell yourself that but the scale and simple math say otherwise.

 

[NeverEnoughFDE]

you can tell yourself that but the scale and simple math say otherwise.

If you're just going to be rude, please stay out of the thread.

 

[LoonWulf]

If you're just going to be rude, please stay out of the thread.

That wasnt being rude, that was simply pointing out that your asking for something that isnt easily attainable.

I did a build on ati omni receivers, pencil barrel, and cut all the weight I could out of the bcg/buffer assembly. With a Bushnell lil P Mounted on a skeleton riser, I want to say that rifle weighed 5lbs 11oz sans mag.

If i wanted to get under 6lbs with a full size optic, just the handguard would have cost what my entire build did....never mind the magnesium receivers and aluminum bcg etc ...

 

[mavracer]

If you're just going to be rude, please stay out of the thread.

Guess in today's world facts are rude, I wasn't raised that way.
In order to get under 6 with a optic that weighs near a pound you're gonna need to get the base down around 5# you're not gonna get there starting with a barrel that weighs 1 lb 10 oz and a standard weight BCG.

Faxon ION-X Hyperlite 5.56 Rifle

Faxon Firearms Ion-X Hyperlite Modern Sporting Rifle | Rifles, Pistols, Rifle barrels, AR-15 parts, Pistol Parts | faxonfirearms.com

faxonfirearms.com

 

[LocoGringo]

. No need to be rude

If you're just going to be rude, please stay out of the thread.

Man, you're awfully sensitive. No one is being "rude". People are making suggestions and presenting facts and you're outright rejecting what is being presented. You new to the internet? Being a Gen X'er, I figured you'd have thicker skin, but whatever...

 

[NeverEnoughFDE]

Guess in today's world facts are rude, I wasn't raised that way.
In order to get under 6 with a optic that weighs near a pound you're gonna need to get the base down around 5# you're not gonna get there starting with a barrel that weighs 1 lb 10 oz and a standard weight BCG.

Faxon ION-X Hyperlite 5.56 Rifle

Faxon Firearms Ion-X Hyperlite Modern Sporting Rifle | Rifles, Pistols, Rifle barrels, AR-15 parts, Pistol Parts | faxonfirearms.com

faxonfirearms.com

Switching BCG, without going low mass BCG, saves 3 oz.

 

[mavracer]

Switching BCG, without going low mass BCG, saves 3 oz.

The barrel is the biggest difference at a 7.6 oz savings from the one you have. They pull another couple off cannibalizing the upper and lower.
Really there isn't much else to it. Like you said the MFT would get a bit if you want to go that way.

 

[6.8 hunter]

Just a thought, if any sustained fire will be needed, slightly heavier barrel is a heat sink and that is a good thing!

16'' Mid Length Heavy Profile Barrel Kit

Del-Ton, Inc 16' Mid Length Heavy Profile Barrel Kit. 16' AR-15 AR15 barrel kit includes barrel, handguards, gas tube, delta ring, front sight assembly and flash hider.

www.del-ton.com

 

[CraigC]

Might be something wrong with your scale, no way is the Primary Arms micro a pound. I have two or three of the 3x's and they're flyweights. The Gen III is 18oz, did you get that one instead?

Aside from the optic, where way too many people opt for a portly 30mm LVPO, the two biggest places to save weight are the free float tube and barrel profile. Beyond that, you're spending hundreds to shave a few ounces. This 16" 6.5Grendel came out to right at 7lbs with the Vortex 5x prism. Slightly more with the ACOG it wears now.

 

[bassjam]

You did fine building a light AR, it's the accessories that are killing you. But if you want to lose more weight on the gun itself don't fight the suggestions that are being given to you:

• Pencil barrel, or at a minimum Faxon gunner profile
• Adjustable gas block
• lightweight BCG
• lightweight buffer
• handguard long enough to just cover the gas block

Beyond that, rather than replacing the stock to shave a few ounces I'd remove weight at the other end to help with balance, starting with the rail covers and hand stop. An ultralight build is also a minimalist build.

 

[Skylerbone]

An ultralight build is also a minimalist build.

That was my very first thought, glad you had the good sense to voice it! Well put.

 

[NeverEnoughFDE]

Might be something wrong with your scale, no way is the Primary Arms micro a pound. I have two or three of the 3x's and they're flyweights. The Gen III is 18oz, did you get that one instead?

Aside from the optic, where way too many people opt for a portly 30mm LVPO, the two biggest places to save weight are the free float tube and barrel profile. Beyond that, you're spending hundreds to shave a few ounces. This 16" 6.5Grendel came out to right at 7lbs with the Vortex 5x prism. Slightly more with the ACOG it wears now.

View attachment 1198961

Might be the scale. I put the 5x (with the piggy back mount & red dot on it too) and it said 0.9 lb. I put the 3x micro prism on & it says 11 oz.
I have a new scale coming today so I will weigh them again