I want build a light(ish) weight ar10 (eventually): suggestions welcome

[greyling22]

I'd like to build a lightweight ar10 in 308. I know that parts don't go together like an ar15 so it will be a little trickier.
I'm not in a rush, so I don't need to pay current exorbitant pricing. I'd like to build one on something of a budget. But everything is SO heavy.

I could probably do something like this faxon pencil barrel https://faxonfirearms.com/16-big-gunner-308-win-mid-length-4150-nitride/
but BCG, upper/lower's etc. Anybody have any recommendations for what I should be looking at.

 

[gotboostvr]

There's definitely some weight savings to be had, but what's your total budget?

Shaving alot of weight can get expensive, just a little lighter than normal can be done affordably however.

 

[earlthegoat2]

Pencil barrel and lighter than normal stock is very doable and is a noticeable weight savings. Space age (carbon fiber) hand guard and skeletonized bolt will set you back a lot for a small marginal weight savings.

Or just buy a ROAM R10.

 

[greyling22]

I'd like lighter than normal, but no space age nonsense. Short pencil barrel, check. After that, is there weight savings to be had in the upper/lower? I know my billet ar upper is noticibly heavier than my forged one. And there is some outfit called F4 defense that sells a "small frame" ar10. And wasn't there a dpms g2 that was a little smaller?

My budget is going to be under $1000 for the whole gun, minus optics, in 2018 dollars. Again, I'm not in a rush. I'm just a little tired of wishing my ar15 hit harder. I've tried, and like the Grendel, but there is just nothing that hits like a 308 that fits in an ar15.

 

[gotboostvr]

You can try and pick up a forged "slab side" upper reciever. It's a normal reciever, minus the forward assist. That'll save you an ounce or two without costing much more.

Theres some inexpensive free float tubes out there. As well as optic mounts. I belive Aero makes about the lightest of both and neither are terribly expensive.

Some weight can be saved as well with smart shopping for optics. Leupold typically comes in a few ounces lighter than most.

 

[BreechFace]

Not much weight is saved by going with a carbon fiber handguard (I have a Coda Arms one) and the new Aero handguards as @gotboostvr stated are nearly as light and about 1/2 the cost. The Aero scope mounts are very lightweight and great mounts, and affordable.

I really wanted to get a DPMS Gen II receiver set for a build just as you are wanting to do, but sadly they are not more. Would like to hear more about the F4 Defense "small frame" receivers, but it seems they don't sell just receiver sets. I don't buy off the shelf rifles, prefer to assembly myself.

There are also magnesium receiver sets to save money, they've interested me in the past.

Leupold optics are a no brainer, they are typically the lightest in their class and great optics.

One can get into Titanium BCG's and trim buffer mass and tuning with a custom gas port size or adjustable gas block. But this adds up quick as Ti BCG's are ~$400 by themselves , but only weight ~5.5-6oz. And this would require some know how on tuning.

 

[greyling22]

I wonder who wound up with dpms/Remington's ar business post breakup. I wonder if there's any hope for a resurrection of the DPMS Gen 2 frame size. I don't guess we'd be lucky enough that Palmetto scooped them up and will release an ar10 gen 4

 

[vkeith]

Check out V7. They have lots of lightweight parts but most are $$$.

Smoke Composites makes some very light buffer tubes/stocks and handguards out of carbon fiber but they are $$$ also.

A member of another forum has built an under 4 lb. AR10 in .308 but with all the work and lightweight parts he has in it, it had to be very expensive, but it is possible.

 

[gotboostvr]

I'd bet a #4 AR10 would be a joy to carry and a pain to shoot.

 

[Garandimal]

Springfield Armory SAINT Victor .308. (7.8 lbs w/ flip-up sights)

​

GR

 

[marksman13]

My Aero Precision M5 is 10.4 lbs with a full ten round mag, Vortex Strike Eagle 1-8X scope, and Thunder Beast Ultra 7 suppressor. It’s got a Faxon Big Gunner 18” barrel on it. It feels much lighter than 10 lbs.

 

[earlthegoat2]

I wonder who wound up with dpms/Remington's ar business post breakup. I wonder if there's any hope for a resurrection of the DPMS Gen 2 frame size. I don't guess we'd be lucky enough that Palmetto scooped them up and will release an ar10 gen 4

The parent company of PSA did in fact acquire DPMS. The only reason I can think that it was a good move would be for PSA to further develop the G2 components that DPMS started.

 

[gotboostvr]

The parent company of PSA did in fact acquire DPMS. The only reason I can think that it was a good move would be for PSA to further develop the G2 components that DPMS started.

I could see them using the DPMS label as their "Budget" line and trying to move the PSA line as more of a premium line up.

I am excited someone might run with the GenII frame though.

 

[Uffdaphil]

My Aero M5 came in at 8lb 6.6 oz. with an 18” Faxon lightweight barrel. That's with an 18 oz Lantac enhanced BCG. You could shave nearly 10 oz with an Aero BCG.

 

[BreechFace]

Something to always keep in mind is weight savings towards the front of the rifle pay bigger dividends in how the rifle will feel, and having a bit of weight in the stock location isn't a bad thing. So I would prioritize barrel, handguard, muzzle treatment, suppressor weights over buttstock, buffer weights, when spending money.

The BCG is a place to save a significant amount of weight as said by @Uffdaphil if one can get the gas system right with the lighter reciprocating mass.

 

[Uffdaphil]

Since I run my .308s suppressed, I figured the heavier BCG would be helpful tuning with the adjustable gas block. Plus the forward directed gas from the carrier out the ejection port does seem to diminish gas to the face.

 

[BreechFace]

Since I run my .308s suppressed, I figured the heavier BCG would be helpful tuning with the adjustable gas block. Plus the forward directed gas from the carrier out the ejection port does seem to diminish gas to the face.

I see you are running an SLR handguard are you running their AGB? I use SLR AGB's on all my builds.

 

[gotboostvr]

My Aero M5 came in at 8lb 6.6 oz. with an 18” Faxon lightweight barrel. That's with an 18 oz Lantac enhanced BCG. You could shave nearly 10 oz with an Aero BCG.

View attachment 978401

That's a good looking paint job, and the weight is just about right.

 

[Uffdaphil]

Yes, SLR rail and AGB. I love that they offer many oddball lengths. On my shorties the suppressor fits so close.

Cerakote, not paint.

 

[greyling22]

I like that paint job Uffdaphil.

from what I'm seeing, it kind of looks like an ar10 weights 8lbs-9lbs, depending on barrel length, before optics. and a typical ar15 weighs about 6.5lbs. does that sound right?

 

[BreechFace]

If you take @Uffdaphil's AR10 and back off 10 oz. for the lighter BCG your in the 7-3/4 # range and could further reduce the weight going down to a 16" lightweight barrel, but for me the 18" makes sense in 308 Win.

But yes, with a budget friendly "lightweight AR10" one would be in the 8-8.5 lbs range pretty affordably. Try getting below 8 lbs. with a 18" barreled AR10 and the cost starts creeping up fast. Ask me how I know, I've been researching a lightweight AR10 for a couple of years and just keep coming back to the AR15 with heavier hitters such as 6.8 SPC and 450 BM. But one day I'll fall off the wagon and go all out on a lightweight 10.

Another option to consider is the 358 Yeti, it seems like the most performance one can get in the AR15 platform.

 

[greyling22]

yeah, the yeti is something I have been looking at a lot. It's not cheap, but cheaper than building a 308 I guess. less range though. same with the 25-45 sharps, 6.8spc and the 277 wolverine.

 

[mshootnit]

The Smith & Wesson M&P10 is built to be light. So comparing this one with several Armalites, the receivers are more compact, the Bolt carrier is lighter, the Barrel itself is a lightweight 18". The muzzle device is big but I am not sure if it is heavy. You could shave some off from a standard M&P 10 but not much. The Armalites feel bigger and the 16" is still heavier than the 18" Smith&Wesson. But I still like the 16" Armalite a lot. I like them both. The 20" Armalite starts to get you to an objectionable weight in my opinion.
So long story short, since the M&P-10 starts with more compact receivers, and a light 18" barrel, I have never felt the need to build on the 308 Platform.