Jump to content
308AR.com Community
  • Visit Aero Precision
  • Visit Brownells
  • Visit EuroOptic
  • Visit Site
  • Visit Beachin Tactical
  • Visit Rainier Arms
  • Visit Ballistic Advantage
  • Visit Palmetto State Armory
  • Visit Cabelas
  • Visit Sportsmans Guide

AR .308 - Keeping the Weight in Line


MajorJim

Recommended Posts

Still in the middle of my first build, but one thing I have learned is that is all too easy to end up with a heavy rifle.  Lots of great parts out there, but a lot of those come with a weight price.

Some of my random comments/observations (your mileage may vary):

Stock - the Magpul PRS stock is great.  There are other great rifle stocks out there as well.  They are all heavy relative to carbine length stocks.  Maybe a carbine stock  is the ticket for a lwoer weight platform.

Barrels - longer means heavier, as does thicker.  Fluting not only helps cooling, but it also helps to reduce weight.  Then there are the carbon wrapped barrels, and Lothar's aluminum option.  But carbon and aluminum come at a price over twice the price of a stock barrel. 

My own view is that a 16" barrel is probably OK for 400 or 500 yards.  If you want to go out to 600 yards maybe an 18" barrel is best.  Over 600 - 20 and up. 

Barrel diameter - still figuring that one out. 

Receivers - looks like someone is paying attention - SI Defense's  GenIII Receiver looks like it is 15% lighter than the DPMS receiver.

Forearms - Just how many rails is enough?  See comment on Tacticool accessories below for my thoughts.  The more rails you have, the more weight.  As with jumping from carbine, to rifle to LONG forearms.  Carbon is great, but it comes at a price, and there is not a whole lot of difference between carbon and some aluminum set ups.  I'd go with a slick forearm you could add rails to.

Scopes/Glass - the higer up in magnification you go, and the larger the diameter of the objective as well as the larger the diameter on the housing, the more weight you add.  Try to match the scope power to the ranges you will be shooting.  No sense mounting a 72mm 25 power Hensholdt "Hubbel" on a rifle used on a 100 yard range.  Larger objectives are for lower light and longer ranges.  The 30mm range will hit most needs.  44mm is nice for longer distances and lower light.  50 -56 mm pretty much 1000 yards.  72 mm for targets orbiting Mars.  Larger diameter housings are for light gathering and reticle travel.  Again, 30mm will be just fine for most of us, but 34mm and up will take you way out there, provided your scope has the appropriate reticle travel built in.

Tacticool accessories - lights, lasers, range finders, night vision, infrared, thermal devices, target solution calculators, levels, etc.  Great for static positions or manning the Maginot Line.  Try carrying it.  If that is what you are into, go buy a 50BMG.  the rifle you are building will end up at about the same weight. 

I'd be real interested to hear other thoughts on the topic.     

Link to comment
Share on other sites

Most of the different parts/components out there for the AR, came about due to a particular need, either perceived or real. So as is always the case, you need to match your components to that need, and to work well with each other. The super light CF competition FF tubes usually serve one purpose, to give you a place to hold the gun without burning your hand (and to protect the gas tube so I guess that's two) If you have a need for more than that, like mounting a bipod or BUIS, than you start to need rails, and the weight starts to go up. If you know that you'll never change your accessories than  you can just mount rails where needed and save some weight, most of us don't know for sure about that so a fully railed handguard allows us to try different setups to see what works best.

Same for barrel length, if your building a long range gun your going to need the longer barrel, and consequently, you are going to be building a heavier gun, no way around it. Same for the optic, as you stated, doesn't make sense to put 1000m optic on a CQB carbine build. As you also stated, the stock can add or save 1.5 lbs on your build, with the ACE fixed being the lightest I know of, but sometimes the extra weight of a heavier stock improves the balance of the gun in such a way that the extra 1lb added to the total weight is worth it. Same with rail length, most agree that you want the handguard to cover the gas tube, but different gas systems  IE carbine,mid,rifle are all going to give different gun performance , and will also limit what the shortest handguard you will likely go with. I think it's all about taking weight where you can while not compromising your planned purpose for the rifle.

Link to comment
Share on other sites

  • 3 months later...

thanks for the great info...Im still in the process of researching my 308AR build. My plans are for my weapon system to be versitile. To be able to change the system from a hunting platform to a home defense platform. The weight makes a huge difference from hiking miles on end to hunkering down. Again thanks for the breakdown and adding another variable to the equation for me to consider.

<thumbsup>

Link to comment
Share on other sites

Just a couple of thoughts. 

M1 Garand, 9.5 to 10.2 lbs depending on stock wood density.

1918 BAR, 16 to 24 lbs depending on the configuration (and the standard ammo belt

                had 6 double mag pouches for 12 20-round mags of 30/06).

Thompson submachine gun, 10.6 to 10.8 lbs empty.

1903A1 Springfield, about 9 lbs depending on the wood.

The M-14 is 9.8 lbs empty.

The 20" Panther is 11 lbs.

My 16" 308T is 8.5 lbs.

The 16" collapsible stock Sportical is 8.3 lbs.

Cowboy up. Grandpa carried a BAR all over Europe and Korea.  I'm 4" taller and 35lbs heavier than he was.

John

Link to comment
Share on other sites

Cowboy up. Grandpa carried a BAR all over Europe and Korea.  I'm 4" taller and 35lbs heavier than he was.  John

Man!  That IS one big elf!  <laughs>

I kinda think the same way.  If you've held a loaded Tommy Gun to your shoulder, then think about humping that thing all over creation for weeks at a time, you should be able to do the same with a nice .308 and 20 extra mags.

Jon

Link to comment
Share on other sites

Just a couple of thoughts. 

Cowboy up. Grandpa carried a BAR all over Europe and Korea.  I'm 4" taller and 35lbs heavier than he was.

John

<lmao> <laughs> <laughs> <lmao> phew, that's funny. now, i realize we can get heavy, and think that it's reasonable especially when compared to other battle rifles and such, but you can get too heavy to carry around. my larue as it sits in my safe is about 14.5- 15#'s give or take, and i would want to carry that battle style for long. my pws is just a tick under 11#'s with a loaded mag, and seems much lighter but not a feather. i am satisfied with both for what they are, and you need to be happy with your build and will eventually have to find a happy medium of weight vs money spent, like you said earlier, it will get expensive. btw, this is why i am going to start a hk usc to ump conversion build after the holidays as it was super light and had good accuracy at 50yds, enough so that it will be a go to gun for home defense and ultra short encounters.

Link to comment
Share on other sites

Now, back to the lighter side.

What is reasonable for the least amount of weight one can put in a 308AR, and still get a reasonable 1.5-2 MOA?  Seven pounds?  Six and a half (I think that would perhaps be too light)?  That would be the cat's meow!

What are some of the lighter guns on the forum?

Jon

Link to comment
Share on other sites

I have a .308 AR I assembled with lightness in mind. It weighs 8.25 lbs with an empty mag and BUIS (no optic) It has a carbon fiber wrapped  18" barrel and a Magpul CTR stock. I think you should be able to get down to around 7 lbs (without optic). I have a full length quad rail handguard on mine. I think the one that Robocop is putting together, with the Apex handguard and Ace ARFX stock should come in at least 1 lb lighter than mine. Both of these guns should exceed 1.5 MOA accuracy. I'm thinking that the only way you'd get one much lighter than that would be if you went with a 16" pencil barrel, bare carbon fiber FF tube like the Clarks, and maybe go with a lightened bolt carrier group.

There's a guy that makes a hybrid type AR that is a cross between a small frame and large frame AR that's supposed to be very light, but I think it uses a proprietary upper that allows him to use his own AR 15 type barrels but .308 barrel extension and AR 15 hand guards. I think the company is AR performance, and if you don't mind having to buy your one off replacement parts from only that source, it might be an option for you.

Link to comment
Share on other sites

  • 3 weeks later...

Here's the linK to the company. The gun I'm refering to is the ITS 12 .308

Hi Jgun    Harrison "H" as we know him is not planning on this anytime soon....he is going to have some light barrels coming out though  .....whenever this platform is available im on the list...he produces awesome products!      Wash

                              http://www.ar15performance.com/home

                       

                         

Link to comment
Share on other sites

I have much interest in this as well.  I would love a 6.5 lb .308 styled AR, but will settle for one at 7lbs flat.  A thin, fluted 16 inch barrel should save a lot of weight.  How does one go about safely "lightening" the bolt/reciever groups? 

Drill or flute where it won't weaken its structure?  Use heavier springs to slow the bolt down to compensate?  <munch>

Link to comment
Share on other sites

As long as you keep in mind that a light 308 is going to punish your shoulder more , even with a brake on the bbl..

If you want a light barrel , forget the flutes , they are cut into HB to lighten them up & try to keep the stiffness needed to have a tighter grouping barrel , you can get a lighter barrel with out the flutes.

Link to comment
Share on other sites

-ADCO will contour for a reasonable price-big questions are to send the AP4 upper in, or buy/build a new upper.  The AP4 weighs 8.2 lbs no mag, no sights.  I guess forget the lightened BCG-thanks for the advice.

Oh, Life is pain.  I eat 45/70 Buffalo Bore's on a chopped Marlin and 3 inch 12 Gauge 15 pellet Magnums for breakfast. 

Thankfully, breakfast is only served once  <laughs>

Link to comment
Share on other sites

-ADCO will contour for a reasonable price-big questions are to send the AP4 upper in, or buy/build a new upper. 

ADCO prefers to just receive the barrel, only, when performing barrel work.  If you send in the whole upper, you'll need to pay them to strip it down and remove the barrel, then build it back up after the barrel work - unless you'll build it back up yourself.  Didn't know if you were aware of that or not. 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...