The Quest for the Ultimate in a Lightweight KISS Carbine

[markm]

The ultimate light weight carbine (to me) is the BCM KMR 14.5 middy. Run an H buffer in it, and it's also one of the smoothest shooting ARs. Even with the Arisaka light on it and an optic, it's goofy light and smooth.

[SethB]

FSBs are heavy. Using a small or cut down gas block with an MLOK rail over it and a front sight bolted on will be about two ounces lighter.

The lightest rifle I've owned was a 6520 barrel with a 604 slick upper.

It was very light and very useful at short range.

[Dr. Bullseye]

I've been on a soul-searching journey toward the ultimate in simplicity and especially light weight in a fighting carbine. My accessory-laden M4 is getting to be just too dang much of a burden for my 50+ year old arms (getting old sucks), and I hit upon the idea to strip as much off as possible and go with the absolute minimum setup.

When I got my Pennsylvania State Police Colt 6520 with fixed carry handle, pencil barrel, and flashlight-handguard, I realized that's where I needed to start. Even though I wouldn't stick with that big honkin' flashlight setup on the 6520, it did give me ideas...

That means going "doodad-free" as much as possible.

I decided to try to build a KISS carbine with emphasis on light weight using off-the shelf items. I didn't want to just mount a lighter weight flashlight setup on the 6520 because I wanted to keep it pure, and I also wanted a flat top AR to be my go-to once I decide on an optic.

I started with the Colt 6720: basically an M4 with the pencil barrel.

I tested my favorite optic, the Meprolight M21, inside the house with a bright weapon light, and the reticle washed out badly. I had never used that optic anywhere but outside at the range and at the ranch. I was not expecting it to be that bad against light-colored walls with the Surefire on. I actually had a better sight picture with the large A2 iron aperture.

I was able to use the large rear iron A2 sight aperture just fine inside the house with the flashlight blazing against the light-colored walls.

I may go with an Aimpoint T2 eventually, but for now: scratch optic.

Next, I removed the fat M4 handguards on the 6720 and installed MagPul handguards with a quick detach sling swivel, rail for the weaponlight, and weaponlight mounted on the handguard rail. I also installed an AFG to help pull it into my shoulder. Still too heavy.

After yanking all that off, I installed a plain Jane set of CAR-15 handguards, a Midwest Industries front sight-mounted rail, and a Surefire G2 with LED kit (that's 2010 calling). Much better.

Even though the 6720 is a flat top, the fact that the large A2 aperture works better against the inside of my house than the Meprolight made me put the carry handle on it for now, even though I think it will get an Aimpoint T2 later. The flashlight only illuminates a few yards in front of me outside at the ranch, so I'm not really giving up some long-range night-fighting ability by using irons only right now. As it's more useful indoors than outside after dark, I decided to make it more useful for CQB than any imagined long-range encounter on the moonlit north forty.

So the bottom line for now is that I've got a bone-stock Colt AR6720 with pencil barrel, carry handle, CAR handguards, Midwest Industries front sight mounted rail, and Surefire G2 in a old VLTOR light ring. Only a lightweight optic and a lighter weaponlight will make me change anything.

That's about as simple and lightweight a setup I can think of using stock parts. I will continue my quest for a lighter weaponlight and the ultimate in lightweight optics, but other than that my KISS carbine is mostly "doodad free" now, and the weight difference between it and my accessory-laden M4 is striking.

Have you set up a lightweight carbine?

OK Doc, question. I get the Meprolight (fiber optic/tritium) not being the brightest dot on the planet. But what are you going to do with the Aimpoint or other red dot if you get one? I mean, how is this going to be set up? Are you going to determine the necessary setting brightness level to avoid washing out and leave it on that setting? Is this not going to half the lifetime of the battery? That may be OK for an Aimpoint, I don't know. Or do you plan to find the setting with a red dot which has a shake awake feature and leave it on that power (but it would be inactive most of the time)?

Also, since this HD rifle's duty is around your house, and you know the rooms and yard well, why not a micro red dot like a Doctor on a riser? It might work better than irons and not much weight difference.

[ThirdWatcher]

... The lightest rifle I've owned was a 6520 barrel with a 604 slick upper.
It was very light and very useful at short range.

That has to be one nice little carbine. I have a 6520 that I’ve purposely left stock (although I installed a BCM FA BCG and a BCM Gunfighter charging handle). I’ve never had the need for a FA (or Case Deflector for that matter). Closest I’ve been able to get to a slick side is on my 6450 9mm Carbine.

[Five_Point_Five_Six]

I put together a light and fast setup recently. I bought another one of the complete Colt lowers Brownells was selling just prior to them being discontinued and a 6933 upper. I put a set of skinny CAR hand guards on it with a Aimpoint micro and a SBA3 brace until I get around to Form 1'ing it. For a light mount, I went with the IWC Mount-N-Slot with the 1" ring and a Surefire G2.

[TWR]

My 6720 has Magpul SL hand guards, a Mossie Tactics light mount on the FSB with a TLR1 HL light, a DD fixed rear sight and an EXPS2-0 on it.

I saved more weight by ditching the BFG sling and using a Way of the gun sling from Frank Proctor.

Not the lightest option but very rugged for a light weight, useable gun.

[Doc Safari]

OK Doc, question. I get the Meprolight (fiber optic/tritium) not being the brightest dot on the planet. But what are you going to do with the Aimpoint or other red dot if you get one? I mean, how is this going to be set up? Are you going to determine the necessary setting brightness level to avoid washing out and leave it on that setting? Is this not going to half the lifetime of the battery? That may be OK for an Aimpoint, I don't know. Or do you plan to find the setting with a red dot which has a shake awake feature and leave it on that power (but it would be inactive most of the time)?

Also, since this HD rifle's duty is around your house, and you know the rooms and yard well, why not a micro red dot like a Doctor on a riser? It might work better than irons and not much weight difference.

I'm going to take my time and look at several options.

[Tx_Aggie]

The ultimate light weight carbine (to me) is the BCM KMR 14.5 middy. Run an H buffer in it, and it's also one of the smoothest shooting ARs. Even with the Arisaka light on it and an optic, it's goofy light and smooth.

I'm with you on that. I have rifle with a 16" ELW fluted upper and it's light enough for my taste with just troy BUS, an Aimpoint micro, BFG sling, and weapon light

[Alpine2k3]

Do 11.5’s qualify? If so, I think a Sionics barrel/KAC URX II make a great combo.


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[Doc Safari]

One option I'm considering is a TA44 ACOG. Being only 1.5 power, though, I'm concerned that enough of the FSB will be visible in the optic that the ACSS ranging capability will be mostly negated. Anybody have any experience with that?