I want to build/ order parts to build a 5 pound M4 in .556.

Has anyone here built one from parts, that I could copy?

Thank You!

You'll be close, with the Robb Jensen 5.86lb gun. Barrel profile is .560 midlength with a Troy TRX 13, a pinned muzzle device, A5 RE, Aimpoint Micro, Daniel Defense fixed sights, JP Low mass carrier, and TLR-3.

You'd pickup a half pound going sights only and no light, but this is a very reasonably equipped gun. Also there's no forward assist: only the plug.

Good luck.

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Sorry for being a total noob,  with everything you just said. I can find via Google? Is this a prebuilt rifle?

Thanks

Don't remember the total weight but it was suppose to be around 5-6 lbs.  I'm in the process of building one myself just so I can have one and not spend $1800 on it

linky

Do you have a parts list blaster ?

Take a look at a Colt 6720.  You should be able to get close with a 14.5" pinned pencil barrel, slick-side flat-top upper, small BUIS like a MaTech, and light weight stock and hand guards.  Maybe an ACE stock, and Clark Custom carbon fiber tube.

Red Jacket has the list of what they used.  Mine will be a Bushmaster lightweight barrel and Rainier arms NON foward assist upper.  Will be using a DPMS carbon fiber free float instead of the one they have.  Other than that not much difference.

Still trying to figure what this means on their list. Internal Parts: Mil-Spec internals. Good luck on your build.

If I had to make a lightweight build, I'd probably:

1) consider a polymer Cav arms lower
2) If i went with aluminum, I'd put one of the new smaller magpul grips or say the troy ax grip on it. CTR stock.
3) lightweight profile barrel. 14.5in (carbine gas I guess), small low profile gas block. get a light muzzle device that's 1.5in long, have someone pin and weld for you.
4) troy TRX extreme rail, or say a clark custom carbon fiber tube. (idk if these can be cutdown?), but I would have that done to it if possible.
5) Slick side upper receiver, or at least one that lacks a forward assist. wasted weight.
6) I guess* I'd go with a non M-16 (ar-15 style) bolt carrier, though i don't know how much weight it would really save off the top of my head?

7) pick an optic. if you go with a troy TRX extreme rail, that might be MBUS. if you went with a clark and a gasblock that doesn't have a rail on it, consider an aimpoint T-1.

?

8) Profit


That's my best shot in the dark. check out the lightweight thread!
Lots of good ideas in there

http://www.ar15.com/forums/t_3_118/527546_Lightweight_AR_Picture_Thread.html

Here's the link.  You'll find an evolution for the parts going from MBUS to DD fixed but mostly it comes down to barrel profile, the TRX, and Micro.  The only 'heavy' object in the gun would be, imho, the Vltor A5 system.  But the benefit is there for a controllable gun.

This.

Actually, OP: Whats your goal? A carbine course ready gun that's light? SHTF/HD/Zombies/Redcoats ready? or lightweight at any cost?

Give us more clues, that way the posters here can help

Well why I want a 5pd AR is because I'm a disabled shooter/hunter. I'm a high level quad, limited arm movement. Feel free to ask anything else, it doesn't bother me to talk about it.

If I were running a 5lb gun:
14.5" carbine running a contour to .570 fore and aft of the gas block
FSB profiled and cut to use rear taper pin
Troy 9" TRX Extreme
H2 or H3 buffer
Rainier slickside upper
no port door or hardware
Aimpoint Micro on DD 1/3 mount
no BUIS
no light
no VFG
A1 pistol grip
MOE triggerguard (polymer)
CAR stock

This whole "light is right and every ounce counts" and "ounces equal pounds and pounds equal pain" mentality is starting to catch on.  My SBR is going to get the barrel contoured down to .700 since it's a 30cal and that will leave enough wall thickness similar to a Colt pencil 5.56 barrel.  I've read some people going to .650 for 30cal bores, but I'm certain losing a bit of metal around under the gas system will do me just fine.

If I was truly weight concious I'd drop the SOPMOD stock, but I can't bring myself to do that

Even my RVG went to the chopping block and I might dimple it a little bit just to see if i can shave off another 1/4 ounce

Good luck OP––-hope this helps your quest sir.

Edit to add: an SBR stamp on your chosen lower.  I hate pinned muzzle devices.

do you want a 5 pound AR, or a 5 pound M-4?
M-4's can't be M-4's without a M-4 barrel.
M-4 barrels are .750" (at least) except for the .625" cut to hang the M203 grenade launcher.
you SAID M-4, did you mean any AR?

A 5 pound AR is a nice number to shoot for, but at a certain point, you get into exotic, non-standard parts to make that number reality... possibly at the cost of reliability.

16" Bushmaster SuperLight Barrel Assembly would be a great starting point. Great barrel and about as light as you can go without asking the BATF permission to build a Short Barreled Rifle.

M16 (slick side) or A1 / C7 upper. If your disability rules out using iron sights, then flattop/red dot would be the way to go.

BCM bolt carrier group

CAR stock http://www.mapartsinc.com/productsDetail.asp?id=1073

This used to have the Bushmaster Superlight barrel... went the SBR route and it now has an 11.5" Colt lightweight barrel.

Yes, AR -in .556 ? Is that correct? My knowledge isn't good on the black guns. I know I want a light .556 cal - due to my arm strength.

lol yes zombies! :) I just want one, no reason.

Thanks for the info!

Thank you :)

exotic, doesn't bother me. Because why I need a 5 pound AR. I'd get more use out of it. I can roll in my chair to the nearest gun range. Yea I'd like a red dot scope.

The 5 pound AR, where do you think I'd be on the price. If I order everything?

Also anyone have a parts check list to follow? I searched the forums...

I ran across this... 5.36 pds. I want it. Anyone have any info it's Robb Jensen - other than whats below?



http://img.photobucket.com/albums/v408/gotm4/Virginia%20Arms%20pics/ProjectFeatherweightApr142011.jpg