.308 or other for my next semi-auto build?

[TwoNiner]

I have a Savage Model 12 LRP in 6.5 creedmoor right now which is a fantastic rifle, but I'd like something that is lighter weight and more compact. My savage has a 26" barrel, which is great in that it gets those 140gr amax rounds to 2700-2800 fps so the cartridge can really perform, but I'd like something that is more maneuverable and lighter weight. Basically something I can have fun run and gunning with in the desert, shooting shorter distances 100-200 yards and long distances here and there at 800-1000 yards. I have a .338 lapua for the LR stuff.

My first idea was to just build an AR15 SPR. Its semi-auto, compact, and cheap to shoot, but of course the issue with the 5.56 round is the BC of even the MK262 ammo is only .395, which at my elevation peters out pretty quickly at distance. Also my experience shows that even a 300 yard shot in high winds with underpowered .223 PMC gets you vanilla results, although if I build an SPR I will use XM193 or BH MK262 ammo.

After poking around on JBM's calculator it looks like the .308 round isn't a night and day difference in terms of effective range, even though there is a night and day difference in ammo cost. I am thinking about doing a 6.5CM in an AR-10 style platform, but it seems 6.5CM factory ammo is scarce, and I don't have the time to hand load 100+ rounds per range trip. It also opens up a can of worms because, as I under stand it, there are different platforms (DPMS, etc) with different specs, and I'm a bit intimidated to build one on my own.

Can anyone offer any advice to steer me in the right direction? Do you guys think I should just continue to build a 556 SPR and see how that works out? Or perhaps seek out a professional (and probably expensive) custom build, and go with the standard .308 caliber and hope to find a good deal on ammo?

 

[Guest]

I have the 2 guns in my below Signature that I shoot at distance. Once is a AR15 Recce with a 16" WOA SS Match barrel. With 77smk loads it was making consistent hits on a 12" steel plate at 800yds this past weekend once I found my hold for the 10-15mph wind. My P308 AR10 was making hits on that 12" 800yd plate childs play and was hitting the 24" gong at 1000.

I would say it depends what you want to do with your gun. I wouldn't hunt with the AR15 at distance but don't think with the right precision AR15 setup you can't be accurate at distance. Love my AR10 and with handloads its extremely accurate, especially at distance.

 

[Luke]

but I'd like something that is more maneuverable and lighter weight. Basically something I can have fun run and gunning with in the desert

FWIW: I sold my POF 14.5" P308 earlier this year, primarily due to the fact that when you get it set up to be a solid 800yd gun with optics, bipod, etc. it's too heavy and bulky for running and gunning. I've since moved to a 14.5" AR-15 platform and it's a great rifle for the run & gun application. It's small and relatively lightweight, and with Mk262 ammo 600yds is easy peasy, and 800yds isn't hard. For shots less than 800yds the AR15 will do it lighter, faster, and cheaper.

 

[Guest]

My P308 definitely isnt setup for running and gunning. Its setup as a compact precision semi auto. Very accurate.

Now if I want to run and gun I would grab my AR15.

 

[Ledzep]

I say AR15 in 223. 18" 1:8 twist medium contour barrel.

Lighter, effective to 600yd at least for popping steel, less recoil, cheaper ammo, reliable, no surprises, more options.

I agree with the previous post. Once you put optics and a bipod on an AR, especially a 308 frame variant, you're looking at quite a bit of weight and bulk.

 

[Luke]

My P308 definitely isnt setup for running and gunning. Its setup as a compact precision semi auto. Very accurate.

Now if I want to run and gun I would grab my AR15.

Absolutely - different tools for different applications. Sorry if it sounded like I was trying to be negative. I would still have the P308 if my budget could afford to have both! But I had to sell one to fund the other...

 

[Guest]

I didnt think your post was negative.

Now just because my P308 has a 5-20x50 and UBR on it and weighs 13.1lbs empty doesnt mean it cant be setup as a run and gun. Put a 1-6x20 and CTR on it and it easily could be carried.

Heres my AR15 and AR10

 

[LRRPF52]

I know exactly what you are looking for.

An AR15 chambered in 6.5 Grendel. You get:

* ~85% of the energy .308
* Tons of factory ammo that is specifically meant to work in gas operated AR15's 6.5mm grendel ammo rifle
* True compatibility with AR15 parts with just a barrel/bolt combo and mags being different
* You can really have a well-balanced, lightweight carbine or rifle in the AR15 with full advantage of AR15 receiver and furniture choices
* You can actually hear it hit steel at distance compared to 75gr and 77gr. 223 Rem/5.56
* It is great for 800-1000yds with factory ammo from an AR15

I have literally piles of AR15's in .223 Wylde or 5.56, and have built several using CLE, Krieger, BCM, Douglas/HPS, and JP 18" barrels in SPR configurations. I'll never do one again in .223 Wylde unless it's for 3-gun or something like that.

For what you are talking about, wanting lightweight, broad range capability, and already enjoying 6.5mm in your bolt gun, I think you would really enjoy a 6.5 Grendel. Quality Hornady factory ammo is very affordable, even rivaling FGMM and Black Hills for pricing. It also makes an AR15 into a hunting machine capable of all your medium game, and has been used to take big game more than enough to call flukes.

 

[AKONA]

A current service round has a few advantages like the 5.56 and 308 just because ... well .. they are service rounds. But should not be the only determining factor.

The 5.56 ammo like 80gr double tap and amax hornady superformance can get you out there not to hunt elk at 800 yards LOL but they will get you pretty far
and because it is a 5.56 you have all sort of options from very simple and economical to more dedicated specialty ammo. A 18 inch carbine with a shorty brake is
a great performer and a nice compromise in size vs. performance/ speed.
Britts redesigned their service round purposed loaded for their 16" LMT L129A1. Popular service rounds M80 type in 308w are a bit of a waste in 16". 20" is ideal
but might be too heavy so an 18" might be a good compromise but the 5.56 will allow you to carry more firepower with the same weight or less weight for equivalent
firepower. For a 16 incher or even shorter (for whatever reason) a 6.8 makes a lot more sense all the way.
If you want to hunt and more momentum the 6.8 is a good compromise between size, reach and terminal effectiveness and works really well in 16 and 18 inchers.
Smaller barrels might be cool but they are a waste in any of these high power caliber. They sacrifice cannot be justified by anyone who wants to have decent speeds
with decent bullets and more reach ...Double E... (efficiency and effectiveness).
The LBC/Grendel is a great flier. One here needs to be very careful choosing well tuned quality components including bolts. But I guess this is a good practice no matter
what system.
The run and gun can be an absurd concept they way I see it interpreted and executed and it is going to get some good people killed. I think it is a good idea to get familiar
with rifles and pistol training and doing some cirucits and going trhough the paces but any idea that running and gunning /SHTF / major warfare is absurd. In an attrition type
of situation people running around shooting will last 20 seconds against a trained military. Instead the people should spend more time in effective tactics like GTFO sight
and becoming experts at hiding, surviving and getting intelligence. The real weapon is the brain the firearm is just the long arm.

So I would pick up something that is easy to build and maintain, plentiful and with options. Still I like something accurate so good internals and a good barrel is a must.
the rest like the shell / brand and other things is meaningless. Of course make the ergonomics work for what you want too. what feels good to you and works for you
is what is most likely the ideal for you.

I have most commercial ammo tested in all the calibers mentioned above and a few others not mentioned. double tap is one of the few vendors who are accurate with
their load data. hornady are also going hot and consistent. corbon, black hillls, etc...
223 Remington 80gr. HPBT Match 20rds.
At 200 yards the high end 5.56 loads intercept other popular russian and whisper/blackout +P rounds and then continues shooting flatter, further and delivering more energy
with decent amounts of momentum from the 80gr-75gr bullets while the other 308 AR15 projectiles are heading straight to the ground. Wounding in soft targets might be broad
and while not too deep will produce brutal trauma. for hunting TSX 62gr might give great penetration and consistent approach. Also a great defensive round at moderate ranges.
Since you seem to understand ballistics check some of the specialty ammo you have and ponder your options. Do the math.

Some think "da bigga, da betta" but many times less ends up being more in the end. One just needs to be smart and realistic.