Never really felt like the AR15 would be something I'd enjoy...  Don't know what changed up, but the way things are going now days, I am feeling like the need for practical solution to the close to mid range issues. 

Every time I pick up a rifle, I'd think this should be a sub 1/2 moa device with 600 yard plus capabilities.   Thoughts change up, and practical short range rifle, in a capable redily available cartridge just made more and more sense to me.

So being a endless tinkerer I decide I want to try AR15 assembly.   I won't call it build, because all I will really do is screw shit together.  Lol.  This will probably not end up in a way I expect,  however I enjoy the research,  and the process of figuring the workings of mechanical things.  Keeps my mind occupied.

Of course I could just buy one of the MANY reliable options out there, but where's the fun in that. 

I decided I NEED an light AR, after trying a friends sub 6lb rifle,  and being so impressd;  so this is where I begin my adventure. 

Start her off with a nice used VLTOR MUR upper




And try out this new Faxon ultra light 1:8 twist 5.56 Barrel.

nice quality parts to start with. i really really enjoy lightweight ar's. literally half the weight of all of my other rifles(my lightest is 4.8lbs with mbus pros and a red dot)
that mur upper is top shelf and i also own one, but they are one of the heavier uppers out there. i think it weighed a little over 3oz heavier than a non f/a "slickside" upper and over  2oz heavier than a standard milspec forged upper when i weighed a bunch of parts one time.


i have a lightweight .625 adjustable gas block if you need. one is new and one is used for around 30 rounds for test fire. $35 used and $40 for new   there arent many gb options out there for pencil barrels.
i also have a ares armor bcg thats 20% lighter than milspec. $170

Thanks Jay.  Already have a Battle Arms Development titanium GB on the way.  Very light.  Reason for the MUR was friend had for sale and I want a solid foundation.   I'll sacrifice a little weight for add strength and reliability.   Planning on trying a A5 Buffer system and full mass BCG for reliability.

Have you had experience with Faxon Barrels?   Any good accuracy wise?   Don't plan on this being a tack driver, but at least 1 MOA woild be nice. 

well 77s work all the way back to 600

well 77s work all the way back to 600

Might try that!

well 77s work all the way back to 600

Think I can get enough velocity out of a 14.5" ?

Thanks Jay.  Already have a Battle Arms Development titanium GB on the way.  Very light.  Reason for the MUR was friend had for sale and I want a solid foundation.   I'll sacrifice a little weight for add strength and reliability.   Planning on trying a A5 Buffer system and full mass BCG for reliability.

Have you had experience with Faxon Barrels?   Any good accuracy wise?   Don't plan on this being a tack driver, but at least 1 MOA woild be nice.

oh i see. since i saw the 14.5 pencil barrel and the lightweight handguard i thought you were going for a featherweight carbine build.
the a5 system and full mass bcg with the pencil barrel,titanium gb, and lightweight carbon handguard, should bring the balance more rearward so that should be interesting.
i dont own a faxon but in my research for lightweight barrels they came highly rated, especially for the price. ive also seen an employee or possible owner of faxon post on ar15.com that "if you arent happy with the barrel they will make it right" whatever that means.

 ill probably scoop one on black friday if i have spare cash and the price drops below the ~$170 shipped you can find them for nowadays when they are in stock. 
mainly because ive read they are a hair lighter than my daniel defense chf pencil barrel, plus its midlength gas instead of my carbine length.

 

oh i see. since i saw the 14.5 pencil barrel and the lightweight handguard i thought you were going for a featherweight carbine build.
the a5 system and full mass bcg with the pencil barrel,titanium gb, and lightweight carbon handguard, should bring the balance more rearward so that should be interesting.
i dont own a faxon but in my research for lightweight barrels they came highly rated, especially for the price. ive also seen an employee or possible owner of faxon post on ar15.com that "if you arent happy with the barrel they will make it right" whatever that means.

 ill probably scoop one on black friday if i have spare cash and the price drops below the ~$170 shipped you can find them for nowadays when they are in stock. 
mainly because ive read they are a hair lighter than my daniel defense chf pencil barrel, plus its midlength gas instead of my carbine length.

 

Roger that.  Main goal is a reliable weapon at as light a weight as possible, yet not so light and fragile as to be afraid of busting it when run semi hard.   

I got the barrel from Brownells at $170  weights a whopping 16ozs.  Very curious on how well it'll shoot. Updates will be posted here.

Not going to run the PRI, It's just on loan so I could visualize the hand guard.  Maybe later I'll use it for a SPR type build.   Going to run a BCM KMR 13".  The KMR weights less.   

Looking at alot of V7 Weapons and Battle Arms Development items to shave weight here and there.   Trying to calculate things out I am hoping to come in under 5# naked.

You already have the MUR, so no problem.  It is going to be heavier as you know, but I will note that quality mil-spec receivers can go hundreds of thousands of rounds without issue, so don't worry that one too much.  Yes you can get out to 600 reliably with a 14.5, I do it.  I push an 18" with 75-77's out to 1000 with two projectiles in the air at the same time before the first strikes the steel target.

I have a KMR and have mounted several.  They are very nice and lightweight.  Some grumble about the coating on the blend, but they do have the all alum versions available. 

I met Bob Faxon and his wife at the Vegas airport his first trip to shot three years ago and he was still at prototype with the ARAK and mostly had the uppers.  We sat and talked at length and continued to correspond for several months.  I have not used any of his AR barrels, but his machine shop (firearms is just his hobby in the big picture) is AMAZING and his quality of machinery and machine work in general is about the best out there.  He is a stand up guy and he and his wife are very down to earth even as a very successful businessman outside of firearms.  I don't think he would release a substandard barrel as a product.

Now my feelings on pencil type barrels has not been favorable.  I have several lightweight builds and have chased that rabbit down that hole, because I also tinker and do this as a part of my profession.  I have tried most of the top pencil types out there in the 14.5" and up range and they all suffer from heat degrading accuracy.  Many people may not heat the barrel enough at a one round per second pace to notice too much difference in this rifle platform, but slap on a scope, take in out to distance, run the rifle hard and this problem rears its ugly head.  I even notice a distinct shift even at 100 or even as little as 50 yards on 10" steel when running this barrel profile hard and using a red dot.

I do like to save weight in a weapon but where I don't like the trade off is in the barrel.  A barrel with a LW profile or similar is the limit for me as a pencil or similar is not what I personally prefer.  Good luck with the build and welcome to the world of the Black Rifle.  It truly is a very good weapon that fits the role you mention very well.  Feel free to visit over at m4carbine.net.   

Roger that.  Main goal is a reloable weapon at as light a weight as possible.   I got the barrel from Brownells at $170  weights a whopping 16ozs.  Very curious on how well it'll shoot. Updates will be posted here.

Not going to run the PRI, It's just on loan so I could visualize the hand guard.  Maybe later I'll use it for a SPR type build.   Going to run a BCM KMR 13".  The KMR weights less.   

Looking at alot of V7 Weapons and Battle Arms Development items to shave weight here and there.   Trying to calculate things out I am hoping to come in under 5# naked.

sounds like itll be a nice build. i have a kmr on my 14.5 so itll probably look similar to the pic below   

battle arms and v7 make a lot of really really nice stuff but the weight savings on a lot of their lightweight products are minimal for the price. i do want their kmr barrel nut soon though(-1oz). their grip screw and takedown pins hardly made a difference besides corrosion resistance lol.

my simple, USGI issued M4 with RAS and RDS was pretty light as well as an M16A4 I had on my first tour.

You already have the MUR, so no problem.  It is going to be heavier as you know, but I will note that quality mil-spec receivers can go hundreds of thousands of rounds without issue, so don't worry that one too much.  Yes you can get out to 600 reliably with a 14.5, I do it.  I push an 18" with 75-77's out to 1000 with two projectiles in the air at the same time before the first strikes the steel target.

I have a KMR and have mounted several.  They are very nice and lightweight.  Some grumble about the coating on the blend, but they do have the all alum versions available. 

I met Bob Faxon and his wife at the Vegas airport his first trip to shot three years ago and he was still at prototype with the ARAK and mostly had the uppers.  We sat and talked at length and continued to correspond for several months.  I have not used any of his AR barrels, but his machine shop (firearms is just his hobby in the big picture) is AMAZING and his quality of machinery and machine work in general is about the best out there.  He is a stand up guy and he and his wife are very down to earth even as a very successful businessman outside of firearms.  I don't think he would release a substandard barrel as a product.

Now my feelings on pencil type barrels has not been favorable.  I have several lightweight builds and have chased that rabbit down that hole, because I also tinker and do this as a part of my profession.  I have tried most of the top pencil types out there in the 14.5" and up range and they all suffer from heat degrading accuracy.  Many people may not heat the barrel enough at a one round per second pace to notice too much difference in this rifle platform, but slap on a scope, take in out to distance, run the rifle hard and this problem rears its ugly head.  I even notice a distinct shift even at 100 or even as little as 50 yards on 10" steel when running this barrel profile hard and using a red dot.

I do like to save weight in a weapon but where I don't like the trade off is in the barrel.  A barrel with a LW profile or similar is the limit for me as a pencil or similar is not what I personally prefer.  Good luck with the build and welcome to the world of the Black Rifle.  It truly is a very good weapon that fits the role you mention very well.  Feel free to visit over at m4carbine.net.   

Thanks for the great info!  I have read that impact shifts can occur in ultra light barrel, hoping the impact shifts are not too severe.   

sounds like itll be a nice build. i have a kmr on my 14.5 so itll probably look similar to the pic below   

battle arms and v7 make a lot of really really nice stuff but the weight savings on a lot of their lightweight products are minimal for the price. i do want their kmr barrel nut soon though(-1oz). their grip screw and takedown pins hardly made a difference besides corrosion resistance lol.

10-4 on that.  Most small parts are really cutting minimal weight.  The KMR nut is a good one though, it's super light.  Came in at .9 oz on my scale.  Just gotta wait for the KMR hand guards to get back in stock... 

my simple, USGI issued M4 with RAS and RDS was pretty light as well as an M16A4 I had on my first tour.

Perfect.  That's what I'm going for simple and functional.

Also this guy came in too....   .48 oz. 

Vltor A5 receiver extension.   Slightly longer than a carbine extension.   Suppsed to make the system run smoother and more reliable.  Anyone use this? What are your thoughts?   Uses a heavier and longer buffer than a carbine buffer in conjunction wit a rifle length spring.





Kineti tech flash hider with a screw on blast shield.  Drilled for pin and weld to the 14.5.





3 lbs 12 ozs so far......   VSEVEN lower with bolt catch, light enhanced pins, Daniel Defense fixed irons,  Pinned and welded flashhider.

VLTOR A5 buffer (longer than a standard carbine buffer)
Tubbs flatwire spring
V7 57* selector and Ti buffer retainer




Super Tricon

Pistol grip is the ERGO Swift grip
Sights are Daniel Defense fixed
Butt stock is the Battle Arms Development Lightweight

10" KMR hand guard 4.3 oz!  Super light!




Comparing the BCM steel clamp blocks for the KMR to the V7 Titanium clamp blocks.  half the weight.