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Latest AR308 build should be @ 4.5 pounds

31K views 114 replies 16 participants last post by  breastroker 
#1 · (Edited)
The goal is under 4.5 pounds using DPMS Gen 1 AR 308 pattern parts.

My last AR308 got down to 4.99 pounds by 1/5/2016 using the 23 ounce receiver set from Tactical Machining.
The Xanthos receiver set weighs 16.6 ounces so an immediate 6.4 ounces cut.
Also latest CF hand guard is 0.2 ounces less and hoping the next pistol grip will cut between 0.5 to 0.7 ounces.

Upper Parts:
2A Armament Xanthos Upper receiver 7075 T6 @ 9.00 ounces
X-Caliber 416R 16 inch fluted barrel @ 31.3 ounces
2A titanium gas block @ 0.60 ounces
Gas tube mid length @ 0.80 ounces
titanium muzzle brake @ 0.65 ounces
Clark Custom Aluminum barrel nut @ 1.18 ounces
AR 308 carbon fiber hand guard 1.60 ounces in mid length 10.5 inches
Toolcraft Titanium 308 BCG @ 11.80 ounces with ti firing pin
Vltor charging handle @ 1.25 ounces



Lower Parts: Total weight 18.60 ounces with SSA-E trigger

2A Armament Xanthos lower @ 7.30 ounces
Mag Pul K grip @ 1.7 ounces
V7 titanium grip screw 0.113 ounces
V7 Mag catch aluminum 0.173 ounces
V7 Aluminum/titanium selector 90 degree 0.293 ounces
V7 aluminum AR 308 takedown pins 0.26 ounces
V7 tool steel bolt catch 0.31 ounces
Smoke Composite stock 3.3 oz.
AR308 carbine buffer (no weights) 0.85 oz.
NF polymer trigger group 0.65 oz with titanium trigger pins
SSA-E trigger group 2.6 ounces with titanium trigger pins

DPMS carbine buffer spring @ 1.5 ounces
Titanium buffer retainer, mag catch plunger







Will be using the Leupold 6-18x40 Mark AR MOD 1 Riflescope @ 15.2 ounces and the Aero Precision 1" mount @ 3.0 ounces
 
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#3 ·
Low Recoil already

If the last 4.99 pound didn't kick then the same barrel, BCG and gas system will be equally low on recoil. Remember I am gimpy, BAD right shoulder.

Yes there is a push when I fire the rounds, but if I can fire 40-60 rounds each time at the range then just about anyone can. Only a little more recoil than a 6.8 with 140 bullet.

Normally this rifle will have a SSA-E trigger and a V-7 Furion titanium muzzle brake. But like a boxer for weigh in, I will use the polymer trigger group and ARP Shorty brake for weigh in. The Shorty is perfect for hunting, just not enough recoil reduction for me to shoot 60 rounds.
 
#7 ·
Just got an email from the general Manager at 2A, the "Xanthos lite receivers are out at hard anodize we expect them back tomorrow".

"We are in the process of activating the Xanthos-lite on the website, but
already have brisk demand for these coming out of Shot Show. "

Mine will ship this Friday, so go ahead and order from them direct as they will sell out quickly.

 
#8 · (Edited)
ebay titanium muzzle brake only 0.67 ounce

Every once in a while I score on eBay. Just got a titanium 308 muzzle brake 5/8-24 thread that weighs half an ounce less than any other if the seller is correct. Half an ounce is huge when at the front of the barrel. About 0.87 ounces less than my titanium Furion brake. Looks like the Weatherby Accubrake, there have been many others that look like this with the spiral hole patterns. The good thing is it doesn't need to be clocked.

Listed at 0.67 ounces. And only $55 with free shipping. Shipped the next morning.

Ruger precision rifle rem 700 30 cal 5/8x24 tpi Titanium Muzzle brake .750 o.d.
Our titanium muzzle brake is a great addition to your Ruger precision rifle, rem 700 or any rifle threaded with 5/8 x 24 tpi, With an internal parabolic taper our brake reduces recoil while not making the brake overly loud. and weighing in at .67 oz. it is great for lightweight builds. We manufacture all our parts in house! allowing us to offer our titanium accessories at unbelievable prices! military/service discount offered

One of the things I really like is I can remove the gas block without taking off the muzzle brake!




 
#10 ·
Smoke Composites stock

I have to say I love the Smoke Composites stock, with castle nut and end plate it weighs 3.55 ounces. I love it because there is no AR twang.

It is so comfortable to shoot, even with the big bad AR 308. Depending on how the 2A receiver set is configured, I usually do not use the end plate.

if you notice the two take down springs, one is shorty because it is configured to be used with a 4/40 set screw to hold the rear take down pin in.

 
#13 ·
So right now I am at 8.55 ounces for lower parts, so if the lower weighs 8.8 ounces than the complete lower will be @ 17.05 ounces with the NF polymer trigger set.

It would weigh 18.60 ounces with the SSA-E trigger. Pretty freekin lite for an AR 308 lower. I like the 2A a thousand times better.

The polymer AR 308 lower I got last month was 16.15 ounces with the NF polymer trigger and 17.2 ounces with the SSA-E trigger.
 
#15 ·
My extra Tactical Machining upper receiver was cut from 11.7 ounces down to 9.70 ounces. Probably going to put the JT 18 inch barrel on it eventually. I have the DPMS SASS barrel that needs a receiver too.

But for this next AR 308 build I will be using the 2A Armament receiver set. Initially I will use the 33.8 ounce JT barrel for this build.

But I will be getting the X-Caliber 16 inch barrel soon, if the exact same outer dimensions of the 2A barrel are used this 36.4 ounce barrel should be 2 ounces LESS than the JT barrel. Both use the same 416R barrel material, similar fluting. The gas block pad does not need to be 2 inches, modern titanium gas blocks are 1 inch. Want the muzzle end to be smaller with no bulge for the brake.

So 31.8 ounces would be good, 30 ounces would be great. Would still be ridged with the fluting, and X-Caliber is match grade.

I need a lighter barrel to get below 4.5 pounds. Faxon isn't selling or releasing their ultra lite 308 barrels yet. Boooo
 
#16 · (Edited)
BAD NEWS Xanthos receiver set is not 16.6 ounces

Just got this from the 2A General manager:

Upper is coming in right at 9.0 oz, Lower is 7.3 oz (in the white, not anodized, just measured, shouldn't change). That puts the set right at 16.3 oz,
So I have to work hard and refigure the lower weight, wahh wahh!

So right now I am at 8.55 ounces for lower parts pistol grip and stock plus the spring and buffer, so if the lower weighs 7.3 ounces than the complete lower will be @ 16.50 ounces with the NF polymer trigger set.

It would weigh 18.05 ounces with the SSA-E trigger. Pretty freekin lite for an AR 308 lower

 
#19 · (Edited)
I was thinking about one or two holes in the bolt catch finger pad like BAD. unfortunately the BAD enhanced is way too heavy

Also my official sight will be the Vortex Venom @ 1.1 ounces, but only for when the 16 inch barrel is on the rifle.
As soon as I get the receiver I will use the old faith full Vortex Viper 8-24x50 scope, to see how the Hornady ELD-X ammo shoots in the JT 18 inch barrel on a 4.5 pound AR 308. Copper Creek Ammo loaded with Hornady brass and 4064 powder. It sucks they don't let you know how much powder they use, just colored bands. But I weighed all the ammo and they really only loaded 3 different loadings. So I expect they think they will be most accurate with the largest load of 4064.
 
#20 ·
Lol I was kidding. I'm pretty stupid about a lot of things but even I wouldn't drill holes in that 2A set it looks fantastic. My new cf prepreg ships tomorrow so hopefully in a couple days I'll have a update on grip. I'm gonna be industrious weather warming up high 32 yesterday high in low 60s tomorrow! !! My omega suppressor supposed to be in tomorrow. Gonna throw it on my blkout coyote sbr and sight in my xsight. Might be able to try holing some puppies Saturday night.
 
#21 ·
Lol I was kidding. I'm pretty stupid about a lot of things but even I wouldn't drill holes in that 2A set it looks fantastic. My new cf prepreg ships tomorrow so hopefully in a couple days I'll have a update on grip. I'm gonna be industrious weather warming up high 32 yesterday high in low 60s tomorrow! !! My omega suppressor supposed to be in tomorrow. Gonna throw it on my blkout coyote sbr and sight in my xsight. Might be able to try holing some puppies Saturday night.
Sweet! Good luck getting any sleep tonight then! LOL I always get too excited about that sort of thing and can't sleep.
 
#22 ·
Lol no worries I sleep like a rock. I'm a bit giddy though will be half the weight of my specwar. Do wish I'd put a little more research into it and gotten something light that would work with my 6.8sbr. My first attempt at the CF wrapped skeleonized K grip came in at 1.2oz but I messed up and the wrap sunk in some of the larger holes in grip making it funky looking, I've got a couple fixes to try out just lazy in the cold. Breastroker ar10 set he's getting is giving me the sweats but I have to hold off I'm trying to find a six8 set for a special build.
 
#24 · (Edited)
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#25 ·
Titanium Muzzle Brake 0.65 ounces

Got my titanium brake, @ 0.65 ounces. Already ordered another one. If you google Weatherby Accubrake and many others use this spiral pattern for reducing recoil and compensation. No need to clock this bad boy. This is 0.80 ounces less than the V7 Furion at 1.45 ounces.









 
#26 ·
breaststroker--- if you (or anyone else) wants to play around with "re-profiling" a barrel to lighten it up and not worry to much about screwing up an expensive barrel if something goes wrong, you ought to nab one of these when they come back in stock http://www.reloadingbrasswarehouse.com/product-p/308-bl-ap4.htm @ only $120 for a dpms 16" (only issue I see is that it's carbine gas) ... they also have melonite complete 308 BCG for $119
 
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