6.5 lb AR10 Build recipes.

C0Y0TE

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Minuteman
Sep 17, 2014
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I'm looking for your recipes and links to products to build a 6-6.5 pound naked AR10. I'm not sure if I want Creedmoor or 308. As I have lots of practice 308 ammo but no 6.5.

So far I like the Proof Research Carbon Fiber and thinking of going with 18-20"

My Dealer is trying to find out about ordering 2A Xanthos Builder set and Titanium adjustable BCG, and take down pin set.

But I prefer having forward assist.
Looking at Rubber City Titanium bolt because it has forward assist serrations.

Smoke Composite has some hand guards, stocks, and grips out of Carbon Fiber. But I really want slim fore end.

I'm also thinking of using Speed gas block. and SilencerCo Gas Defaeting Charging Handle.

Lets say money is not an issue with this build but don't wan to pay over MSRP.​

My other Problem is most of these parts are out of stock.

If I found a complete light weight AR10 I might go that route. But I doubt anyone makes one 6.5 pounds.
 
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I built this a few years ago, but haven’t played with it as much as I wanted; life has intervened. I plan to run some Nosler Custom Competitions through it over the next year to see what it will really do.

I really like how the speed gas blocks look, let us know how it works for you. I dislike having to have a tool to adjust my gas block.
 
The shortest Proof CF barrel in 6.5CM is 20" and weighs 2 LB 14 OZ. You really do need a full mass bolt carrier group plus some serious buffer mass with the 6.5 CM for optimum results. You won't be able to even come close to your weight goal, I'm afraid.

Here's a rifle similar to what you're describing I built in 2017 using a Proof CF 22" barrel (2 ounces more) plus the 2A Xanthos components along with alloy V Seven everything else. I could have scrimped more on furniture but I planned to actually shoot the thing. Just the bare rifle was 8 LB 2 OZ. It did perform quite well.

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The shortest Proof CF barrel in 6.5CM is 20" and weighs 2 LB 14 OZ. You really do need a full mass bolt carrier group plus some serious buffer mass with the 6.5 CM.
But did you use an adjustable gas block?
My understanding if GB is adjustable lite weight BCG should not be an issue. I was planning on using Speed Gas block.
 
But did you use an adjustable gas block?
My understanding if GB is adjustable lite weight BCG should not be an issue. I was planning on using Speed Gas block.
You can tune the gas for a LMOS, but the range of ammo that will reliably cycle narrows without retuning. If you're talking about the Riflespeed AGB, they are one of the easiest to adjust the gas, but they are also one of the heaviest.
 
Easy button
Add an 18” 6.5 Creedmoor upper
 
I know this is not 6.5 lbs but maybe something I used can help you. I did go with a Proof Carbon Fiber 16" barrel and also wanted a narrow lightweight handguard so I went with the Knights URX 3.1.

I just completed my first build, a 308 carbine, DPMS style. I was focused on weight but trying to balance reliability, accuracy and beauty. Can't have it all so this is what the compromise is. Base gun is 8.4 lbs, dressed out, without the can, it is 11.3 lbs. I "may" change out the stock, to shave some weight, but I had this one from my SR-25 just sitting in a box.

I broke the barrel in and started tuning the gas block last weekend. Ran 150 rounds through it without any issue. It is a smooth low recoil gun. Mean velocity for Federal 149 gr is 2,669 fps, for Federal 175 gr is 2,467 fps. I still have more tuning to do and start checking the accuracy but so far I am very pleased. I was going to wait to post any pictures until I could post groupings but here is a teaser. Attached is also the shopping list if it helps.

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My understanding if GB is adjustable lite weight BCG should not be an issue. I was planning on using Speed Gas block.

This has been my experience on the 6.5 I built above and a 308 in the following picture. If you look close, you can see that the 308 weighs 123 oz or 7.68#. That’s with a mounted SWFA 1-6 which is pretty beefy. It has a Faxon Gunner 16” barrel. The second photo is of an electronic target screen when I was shooting at 600 yards with it using 168 FGMM. The X-ring is 3”, the 10 ring 6”; I’m happy with how it’s shooting. The lower the mass of the bolt, the lighter the buffer can be IF you have an adjustable gas block. The handiness of speed block might actually be worth the weight even over the titanium adjustables I usually run that need a tool to adjust. To go light, it’s very important that you understand how the gas system works and how badly you can damage things if you open it up all the way and pull the trigger.


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I agree with KYAggie.

I talked to V Seven and I'm giving up on getting a 2A armament receiver set. Their customer service is pretty much non existent.

The V7 Barrel is lighter than the Proof. And plan on using Smoke Composite Stock and Grip.
 
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I built one in the 6-6.5lb range several years ago, using the 2A receiver set, all V7 parts, etc...... Adjustable gas blocks AND reloading open up a ton of options.

With that said, you'll mostly have to make compromises on barrel and furniture. The highest proportion of weight savings come with barrel profile. From memory, I think I had a Faxon LW contour in the 22-24oz range.

IMO, 6lb (and below) AR10's just aren't that shootable. It has nothing to do with recoil -- it's simply the parts you have to choose to get a large frame that slim. (ie. fixed sheet of plastic, acting as a stock, on a CF buffer tube, CF woven handguard, etc...) I was much happier at the 7-7.5lb mark.

Ignore everything I said if your goal is to simply "build the lightest gun possible."
 
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This has been my experience on the 6.5 I built above and a 308 in the following picture. If you look close, you can see that the 308 weighs 123 oz or 7.68#. That’s with a mounted SWFA 1-6 which is pretty beefy. It has a Faxon Gunner 16” barrel. The second photo is of an electronic target screen when I was shooting at 600 yards with it using 168 FGMM. The X-ring is 3”, the 10 ring 6”; I’m happy with how it’s shooting. The lower the mass of the bolt, the lighter the buffer can be IF you have an adjustable gas block. The handiness of speed block might actually be worth the weight even over the titanium adjustables I usually run that need a tool to adjust. To go light, it’s very important that you understand how the gas system works and how badly you can damage things if you open it up all the way and pull the trigger.


View attachment 7984577
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Impressive!
 
The biggest opportunities to save weight come from the barrel and handguard. I used the Smoke Composites handguard on my Aero M5 build mostly for its heat insulation properties rather than the weight savings, and I'm a big fan of it. It's rigid, and I love the round profile - reminds me of the PRI forearm, but it's actually light.

Mine comes in over 9 lbs without optic, but that's with a 3.5 lb heavy profile barrel. A switch to a Faxon could easily drop it below 7.5 lbs before optics on a tight budget. Other than the rail and stock (Lancer LCS) there are no lightweight components used - everything is standard mass. You can spend a lot of money to shed ounces, but that wasn't really worth it to me. I'd like to try a lightweight carrier, but it's a lot of money for something with questionable benefits.

I have a spreadsheet of my build list with factory weights that might help you tally up the total if you make a few changes to your components. My goal was to build the least expensive build possible while still using quality components. I included percentages of the total weight, and you can see that the barrel (~30%) and optic (20%) are the biggest contributors to total weight. If you keep those in check, you should be able to get pretty close to your goal. Good luck!

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I used a spreadsheet to plan my builds too. I had a column for price per ounce so I could determine what titanium parts I was willing to pay the up charge for.. There are definitely lighter handguards I could have picked, but I had to cost contain somewhere. These things get costly fast, but it’s worth it in my experience. This is definitely my favorite gas gun; my Blackfeather stocked Scout M1A is getting jealous as is my JRA Rockola barreled receiver and TRW build kit that’s still sitting in a box……I talked AG Composits out of the last M14 stock they built years ago for this build. Maybe this winter I’ll put it together.
 
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This is what kills me on the march scopes. In theory you can pick up a quarter pound by going with one of their scopes over a vortex 1-10. But then you end up losing an ounce after you add that massive uni-mount. And their reticles are goofy. I almost consider a 1.5 by 15 second focal plane. But I just can't get over having to be at 15x to do any sort of holdovers or shoot fast.
I was going to go with the Vortex Razor HD Gen III 1-10x24 FFP until I stumbled on the March Shorty thread. The Venom is 21.5 oz vs the March with everything on it at 18.5 oz.

Tier One makes a QD mount for the Shorty, it's .5 oz heavier. Here is a thread on mounts for the Shorty if it helps.
 
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I'm looking for your recipes and links to products to build a 6-6.5 pound naked AR10. I'm not sure if I want Creedmoor or 308. As I have lots of practice 308 ammo but no 6.5.

So far I like the Proof Research Carbon Fiber and thinking of going with 18-20"

My Dealer is trying to find out about ordering 2A Xanthos Builder set and Titanium adjustable BCG, and take down pin set.

But I prefer having forward assist.
Looking at Rubber City Titanium bolt because it has forward assist serrations.

Smoke Composite has some hand guards, stocks, and grips out of Carbon Fiber. But I really want slim fore end.

I'm also thinking of using Speed gas block. and SilencerCo Gas Defaeting Charging Handle.

Lets say money is not an issue with this build but don't wan to pay over MSRP.​

My other Problem is most of these parts are out of stock.

If I found a complete light weight AR10 I might go that route. But I doubt anyone makes one 6.5 pounds.
if you're not gonna do extended long range target you might get near, carbon barrel and stripped, but it will cook doing taraget work every 8-10 rounds go way off zero and you'll be waiting for it to cool a half hour. mine is 19lbs with 24" bull.
 
Sounds similar to my build on a Xanthos receiver set…. Mine finished out at 8.25# after swapping over to a Spuhr scope mount, a brass catcther mount on the rail, going to a Keymo mount vs direct thread for a can, and with the much heavier KAK bolt carrier with dual ejectors.

i-C6GDf3m.jpg


Was noticeably lighter with no muzzle device, a lightweight scope mount, and the V7 titanium bolt carrier…

i-X6CbG7s.jpg


…older pic with the old scope mount (and its AR15 mini me based on the original Balios Lite receiver set…with matching serial numbers btw), and when I was running a much heavier S&B scope. Basically swapped scope mass for mount and muzzle mass, LoL

i-zQzB47V.jpg


I had a whole build thread with detailed notes, weights, etc. over on the old defunct Zombie Hunters web page, but that’s gone forever now, and I can only find some of the old pics.

Can get you a detailed parts list if needed, but bottom line it was a lot of V7 and 2A Arms titanium parts, Smoke Composite long closed stock, and a Faxon pencil profile barrel. All in cost was right around $6K with the S&B scope…about $1.5K less with the NF scope.

This is primarily a pig gun…not a lot of long strings of fire, and shooting at moving targets after the initial shot, so lightness and maneuverability matters. Pretty happy with it in every configuration.

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I just finished a Xanthos build as well with a 16" Proof in 308 that is just under 6lbs with flip-ups. About to top it with a 3-20 S&B in a NF Ultralight mount that will add almost 2.5lbs. Parts list at the end of my Crtitique my build thread.
 
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