As the title says. I'm thinking about changing my bug out carbine from a 5.56 to a 308. Home defense would be a 5.56 pistol still, but 308 is more better. I know 14.5" barrels aren't optimal for 308 ballistics, but they're not for 5.56 either.

Talk me out of it, or inspire me with pictures.

Opinion time

The first thing that came to mind when I thought about your question was “carbine length” gas system. Shorter gas system= harsher recoil and cycling=increased wear rate on parts.

Disclosure- I’m only just beginning my first .308 ar but have built a couple 15’s

I run a 13.5" out of my LMT MWS...no problems.

308s don't mind shorter barrels as much as 5.56.

Ballistic Advantage has their Hanson profile barrel on sale for $196. It is, however, a 14 inch barrel and not 14.5...that length may affect what you ultimately plan to do, as in pinning and welding to make a legal 16" barrel.

For 200 bucks with a pinned gas block I think it's a steal.

5.56, .308, 6.5 Grendel, 6.8 SPC, .224 Valkyrie, and pretty much any other centerfire rifle cartridge don't suffer much from going short as many people would lead you to believe.

You can build a 14.5" .308 barrel that will match or exceed the hit probability of a 24" .308 barrel at 1000yds, with a simple twist rate change down to 1/9" when looking at spin stability, for example.

14.5" is pretty fast for 5.56, to be honest.  You'll easily get 55gr PMC and XM193 averaging 3000fps from many 14.5" barrels.

Coming from literally 30 years of shooting AR15s, M16s, and M4s, I personally don't see a reason why I would ever buy a barrel longer than 11.5", unless it was a varmint rig.

For .308 Winchester, if one is so inclined to that cartridge in a gas gun, 14.5" will do way more than most people think.

LaRue has some cool 14.5" PredatOBR pics.

Short 308's are nice, really dont see a reason to go longer in 308.

As long as you understand they are going to be a couple pounds heavier they are great

I like the way this is going. I want to do a G2 build to keep weight down. I could live with a 14" barrel as a lot of the 308 muzzle devices seem to be 2" versus 1.5" for their 5.56 counterparts.

And spot on LRR. I remember years ago the common response was "just get an AK if you want a 30 caliber carbine". Glad those tides have changed as there are give of shorter 308 barrels now.

M4hk33, rifle details please. Despite considering a G2 pattern, I'm still not finalized.

When debating on cutting my SCAR barrel I read through a lot of the ‘just get an AK if you want a .30 with horrible range’ but you’ve gotta go pretty short in .308 to start matching AK ballistics. The 14” region definitely has you lobbing a lot more efficient and heavier projectile much faster than an AK.

what option is that with the barrel and upper?  that's nice, would make for switching to 6.5cm easy

LMT MWS
Mloc Chassis
13.5 SS Barrel
Slashes Xtra heavy buffer
Dead Air Sandman K
Magpul ACS Stock
Trijicon 1-8
Leupold Mk4 Rings
Railscales mloc panels
Harris Swivel bipod on Larue mount
MBT Trigger

The G2 is good platform, you just have to ask your self how do you want to set up the rifle, even a G2 is going to get heavy if you hang a bunch of stuff off it.

As configured its around 15lbs but stripped its around 10.5 lbs, or about a half lb heavier than my scar, and I am OK with that. There is no free lunch and I am willing to take the hit on weight to have the ability to drop a 6.5 barrel in it.

I am considering going to a 2-10/3-18 in QD mount pop it off and mount a Micro dot for when its being used as a carbine.  The 1-8 is a little too heavy to use it as red dot and its recticle is a little thick for precision work. Good optic but dont think its right for that rifle

POF  P308 14 inch 308 GEN 4 CARBINE with LAW tactical folding stock, SHEPHERD 1 x 6 illuminated range finding reticle scope model 310 p3 in quick detach ACCUCAM scope mount, VLTOR emod adj stock, POF precision trigger, RAPTOR ambi charging handle, MAGPUL folding back-up sites, grip pod vert frt grip, VICKERS adj  sling, broken shell extractor & bore snake in pistol grip, extra firing pin & cam pin in stock, MAGPUL magazine loaded 25 rds 155 TAP comes in at 12 lbs, 35.25 inches long, 26.75 inches folded.

Keep in mind that the muzzle device has to overlap the ~0.7" of threads before it will begin increasing OAL when pinned. So to get 16" on a 14.5" barrel, you'd need a muzzle device that is at the very least 2.2". That's regardless of caliber.

Not sure what you mean by 308 vs 556 muzzle device length, since they are typically the same length from the same manufacturer, especially if you're talking about suppressor mounts.

I love my 12 inch 308 pistol. Loud as hell. Even with my sandman-s it’s loud. Get a full size can if you suppress it. It’s a heavy bitch too. Reason why I built a 6.5 Grendel pistol. A lot lighter and flatter shooting. If I had to do it all over again, and wanted AR10 system, would go 6.5 CM. Otherwise, stay with AR15 build and go Grendel for lighter system.

The Surefire, VG6, and YHM muzzle devices I'm looking at were all longer in 308. Could just be those specific ones I guess.

16" overall length with pinned MAMS:

My short (ish) 308 is very similar to m4hk33's setup.



I just put it together today for hunting day and night, and some light range shooting. It's the LMT MARS-H with DMR stock, the MLOK monolithic upper and their factory 13.5" barrel.

Short 308's aren't as poor as people assume, they actually do great with short barrels. Labradar from earlier shows with the 178gr Hornady ELD-x I shoot I'm getting 2401fps average.

I shot out to 475yds on IPSC steel which was 3.7mil drop, I think I'll play with this out to 700 (7mil drop) and call it good.

a POF revolution would make a good bug out rifle. .308 and light/compact like an AR15

a 14.5" .308 rifle with a 3X ACOG or 1-4X/1-6X LPV scope is a fantastic bugout gun.  I love the idea and implementation of a compact handy .308 rifle that reach out to intermediate ranges much more effectively than a compact 5.56mm.  Fill it full of 155gr TAP/Amax and you have one of the best performing, nicest fragmenting, accurate and nasty rounds available.  And even out of that 14.5" barrel it will fragment a very long ways off compared to something like 5.56mm M193 or M80 ball.  That being said, it would make a HORRIBLE HD carbine.  I would NOT want to shoot a 14.5" 308 winchester indoors. Nope. Nuh uh. Pass.

Here is my 14.5" .308 with my 11.5" 5.56mm; they are my bugout rifles. The 11.5" is also my HD carbine. Grab the rifles, ammo cans, body armor, and the bugout bag... peace out. Each 50cal ammo can holds fourteen AR15 mags (420 rounds) and five .308 mags (100 rounds). I keep a third ammo can full of loaded pistol mags, shotgun slugs/buckshot, and spare batteries. My .308 has a 51T mount pinned and welded to a 14.5" BA Premium midlength barrel, Toolcraft BCG, RCA adjustable gas key, Black Rain receivers, and JL Billet hand guard. It's the same length as a 16" AR15 and weights just a hair under 9 LBS unloaded as pictured below WITH the scope. The Leupold VX-R SPR and Aero mount are very light.

Tips: Use a midlength gas setup with your 14.5", especially if a suppressor is an option. Also use an A5 or Armalite AR10 buffer tube... NOT an AR15 carbine tube. The AR10/A5 tube with an Armalite recoil spring lets you use common AR15 carbine length buffers (Car, H1, H2, H3, H, etc...), of which there is much more selection at a cheaper price than the stubby 308AR-specific short buffers. The gas on my rifle is set up to shoot perfectly with an AR15 CAR 3.0oz buffer unsuppressed or with a Slash XH buffer when using the supperssor (no gas settings to fiddle with when removing/attaching the suppressor).

Top Photo: Magpul FCS (superior).
Bottom Photo: ACE ARFX-E

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HD & Bugout Carbines:

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I really like that set up.  i go back and forth on a LPV vs my Mk6 3-18. Nice velocity,  are you shooting factory or reloads? I like the LPV 's but the recticles dont really lend themselves to precision shooting, something that standout with the platform.  I may drop my Mk6 on the 13.5, move my 1-8 to the Scar, and do a NF 5-25 on my 6.5.

What can are you running?  any issues with over gassing? Mine is great with a Dead Air Sandmand K and Extra Heavy buffer.  Ejections is at 4 oclock with no can, 3 with can.

I think keeping short 308's within a realistic window goes a long way towards enjoying the caliber.   When i was attempting to push the older Amax's to 1000, the rounds lost consistency. the newer rounds maintain that, but is really the outer limit supersonic performance.

Does anyone know where to find a .308 14.5” midlength barrel these days thatnisnt custom made? The only 14.5” I’ve found is from BA but it is Carbine length gas

wilson combat makes a couple 14.7" with intermediate length gas.  should be quite soft shooting.

Link

Fuck 14.5 and go 12.5!

I got the wilson 14.7 inch ranger barrel for my build. It is nice.

I bought one of the BA Premium 16" Midlengths (unthreaded) and had them pin a gas block on it when they were on clearance/closeout from being discontinued.   Then I just chopped, threaded and pinned the hider myself. Best bet is one of these sent to ADCO or another shop to cut up. It's only $200, an it's a damn fine barrel. I'm thinking of getting another and stashing in the back of the safe for the future. https://ballisticadvantage.com/16-inch-308-tac-gov-midlength-non-threaded-cmv-premium-barrel.html

Two configurations I've found to work fantasic for the 145" midlengths...

This works well unsuppresed, but is still too hard/gassy with a silencer:
14.5" Midlength Barrel
Unsuppressed
0.073" Gas Port
Unregulated Gas Black
AR15 Carbine Receiver Extension
Slash Heavy Car Buffer (5.6oz)
JP 308 Carbine recoil Spring

This works well for suppressed and unsuppressed:
14.5" Midlength Barrel
0.073" Gas Port
Adjustable Gas Block or Gas Key
Armalite AR10 or BCM/VLTOR A5 receiver Extension
Armalite AR10 Spring
Unsuppressed with AR15 3.0oz CAR buffer --or-- Suppressed with a Slash AR15 XH Buffer
I tuned the gas for proper function unsuppressed with the 3oz buffer; then swap in the XH buffer when I attach the silencer (the gas settings stay the same)

Good info and many thanks.

I have one. Can confirm.

Factory 178gr ELD-X



Not the greatest extreme spread but that's the price I pay for using factory ammo with this gun and not loading for it.

Thunderbeast Ultra 7 can. Massively over-gassed with can from factory, solved problem by using Slash's extra heavy buffer. I also have the slightly heavier full auto BCG.

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@bfoosh06

They're the same rifle, just a different buttstock installed. I switched it to the Magpul FCS and BCM A5 buffer tube because the longer tube functions better on an AR10/308AR. Weight is 9.0 pounds unloaded, as configured above WITH optics and sling. It only weighs 7.8 pounds unloaded, with irons only - no scope or sling.

Black Rain Billet Set
BA 16" Midlength Premium, cut to 14.5"
JL Billet 12.8" Handguard
Toolcraft Bolt with RCA Adjustable Gas Key
Magpul FCS, MBUS2 irons and K2+ grip
BCM A5 RE, Armalite AR10 spring & CAR buffer.
Leupold VX-R Patrol in Aero Ultralight mount.
Mixed LPK: DPMS/VSeven/LaRue MBT

Nice.  My 16" maten/rainier match is just over 10 pounds unloaded with ss10x in an ADM recon mount.  loaded with suppressor, it's.....very stable to shoot.  

I really want to a do a big brother type deal for the M4A1 SOCOM.

14.5" barrel, same or similar profile, carbine gas, Armalite AR10 FSB, either the Magpul or USGI style handguards, ACE skeleton stock. But they dont make one in A5 length, or didnt last time I checked earlier this year. Thinking it should be too hard to make one just like it. I have2 short ones, and 1 rifle length. Dont mind scavenging them.

I want the bayonet lug as I plan on making some custom bayonets next year for the hell of it. Ive really wanted something other than the single style for the Ar15 thats out now. Or 2 I guess.

But anyways, I like the idea of 14.5" 308. But no one makes one that I can find. I would prefer standard style, 4140/4150 CMV, chome lined or melonite, but not stainless.

Nice

Not a bad spread even for reloading in a gas gun.  The thing I thought was odd as how a few people out there gave Slashes buffer combo a try with no success.  How is LMT's precision stock, thinking about using it on my 6.5 MWS.

I have been going back on weather I want to keep my Second MWS or Sell it and maybe upgrade an optic or two. who knows

Some of weights Im seeing blow my mind, Im assuming really heavy profile barrels are to blame..  I just built a 18" 6.5 on M5 receivers that weighs 7.8 pounds(7.9 when i moved a larue RAT stock to it)without optic.

aero m5 upper and lower
aero lpk
moe grip
larue mbt2 trigger
aero buffer tube, spring, buffer
aero nitride bcg
bcm mod 0 ch
15" Aero atlas one m lock
18" faxon heavy fluted match barre
faxon lightweight gas block
griffen compact brake

More gas can be somewhat tamed by a heavier buffer, but that is just an easy bandaid that doesn't address the REAL problem... too much gas.

Having had/built six .308 gassers, the slash buffer put in 4 of the troublesome builds was able to make two of those cycle reliably. The other two were still overgassed and I was just trading one set of problems for another. There's only so much that extra weight can solve. Slashes buffer is great - don't get me wrong. It can definitely reduce excessive bolt speed. It can somewhat delay unlocking a bit too - but there can be negative side effects of a heavier buffer. For one, the slash buffer might be able to delay a problematic build enough to now function, but if you're still over-gassed and bolt velocity is excessive then you are BATTERING your bolt catch. The AR10 BCG is already heavy as hell. Adding extra weight to it just exasperates the problem of breaking bolt catches. So you haven't solved the root problem at all, you've only masked it and now you're shooting a rifle that might beating itself to death. If you're going to use a heavy buffer to solve your timing or gas problems in a 308 gun PLEASE PLEASE PLEASE be sure to check your bolt overtravel past the bolt catch. Your bolt catch will thank you.

Better yet...

The 308win case family has a TON of gas compared to 5.56mm (it's literally got 2X the powder) so trying to solve gas or timing or bolt velocity problems in an identical fashion like you would in a 5.56 gun might be a problem with many .308 builds. Allowing the obturated case to relax more before extraction reduces the chance of stuck cases, case rim failure, or excessive stress on the extractor. The two best ways I've found to combat excessive gas are selecting gas systems that are longer-for-length (18"-20" RLGS, 16" RLGS suppressed, 16" MLGS unsuppressed, 14.5" MLGS, and 10-12.5" CLGS) or limiting the gas flow with an adjustable block or BCG or Gas Key. Each of these will be more effective at delaying unlocking and decreasing dwell time to normal levels than simply adding buffer weight... but they'll also naturally reduce carrier velocity AND they'll do it without the negative side effect of beating up your bolt catch or increasing your cyclic mass (flatter shooting), too. Basically, reducing the gas before it ever gets to the BCG going to give you the benefits that alot of people are looking to the Slash buffers to solve for them - with fewer side effects.

Though, I do love the slash buffers and they have their place... just be sure you're not trading one set of problems for another just to get the rifle "running". My best shooting 308AR (the only one I keep now) has a longer gas length, tunable gas key, AND a slash buffer for when shooting suppressed. It's a sweet flat shooter; throwing brass to the 4-5 o'clock and and leaves brass looking beautiful.

I'd be just over 9 pounds if I swapped my ADM mount and SS10x42 for a Leupold 2-7 ultralight and Aero mount.  Yeah my barrel is only 16" but it's a rainier match which isn't necessarily the lightest barrel profile available on the market.  

If I swapped to a Faxon gunner I'd be pretty close to 8 pounds.

I'm happy with where it is though.  I've hunted with it and it's not that bad.  May get shitty in a few years when i'm more of an old man than i already am though.

Sometimes it's not the catch that gets fucked up.


20181015_183224 by Armed Ferret, on Flickr

Definitely gotta crank the gas block closed when the can goes on.  Gonna do load dev without the can, and then (hopefully) it shoots the same load as well with it as it does without it.

I bought a FAL someone had shortened the barrel on.  Then they had a compensator welded to the barrel to get it past 16".

My youngest son took it to an Appleseed.  This was early in Appleseed before the .22 craze started.  The firing line was made up of M1 Garands, M1A's, AR15's, etc.  Centerfire, loud rifles with people used to firing them.

As the morning progressed people began picking their stuff up and moving towards the farther end of the firing line, away from that FAL.  After lunch we found ourselves sort of isolated off to one side with several open yards between us and the next shooter.

I also noticed, at some point that morning, that the grass was gone under the compensator, a hole was forming in the dirt and the grass around the hole was turning brown.  By the end of the day some of dirt in the hole was even turning black/dark.

Sunday morning no one wanted to set up as far as possible from us, again.  I was right next to it, I didn't notice it being objectionable, but all those other men on the firing line didn't want to be near that FAL when it was firing.

Others may have different experiences with short barreled .308's.  I've shot it myself and it doesn't bother me.  Again, I don't notice (from directly behind it) any difference from my M1A.

Yup, I had two DPMS bolt catches snap in less than a few hundred rounds on a 14.5" carbine and 16" carbine 308 gas gun before I realized the problem (excessive overtravel past the catch plus an extra heavy buffer). Which was odd because I've had other DPMS bolt catches last literally YEARS on other 20" rifle gas guns.

Never seen that though. you sure the heat treat is good on that bolt. That's crazy.

The bcg was purchased during the post 2012 election frenzy (although credit to AIM for not gouging and keeping prices the same!!) and manufacturers were working overtime to churn stuff out.  That brought out a higher issue rate than normal, and even though it's literally several years later, bryan was ultra fast to replace no questions asked.  I do love me some AIM customer service, that's for sure.

Got a new one that has a slightly purplish hue (which the original didn't) so i have high hopes.  Already closed off the gas completely and we'll re-adjust from scratch without the can, then with, to see where it needs to be for minimal function to lock back.

It was disappointing to see, but again, AIM made quick work of replacement.

That's slick. Which brace?

looks like the SBA3.

I like their stock, prefer it to the Magpul PRS as its instantly removeable if I want to go to regular stock.

If you’re going to build a CQB bigger bullet number, I’d go 458 socom

All good information that i would say almost warrants a sticky in the variants forum considering the popularity of large frame AR's these days and the number of people experience gas issues.

In regards to my 13.5, I "think" I am good to go. That 13.5 is my forth Gas gun, first was a 22 inch krieger barreled Armalite with adjustable gas system, Second was a 18 inch Mega/Noveske with std gas rifle system.  third/forth are my MWS's

Currently, the shooting impulse/recoil, accuracy, and ejection of my 13.5 is in line with my current 6.5CM Chassis.  I actually ordered a spare bolt catch since i was having some bolt catch spring issues earlier this year.  I wasn't sure what the issue was so i order a complete bolt catch set up.  I took the bolt catch apart and it turned out that turned out that spring/detent and hole were just gunked up from shooting it surpressed for years.  Cleaned it up and is good to go.

Ill keep will keep an eye on the bolt catch but in the event that it goes down, i have a spare.

But then again... Maybe i should just toss the new one in when i get back in the States.  There has to be at least a couple thousand rounds on in now.

Looking for advice here, just bought the Wilson combat barrel as suggested above. Looking to get the longest handguard I can for it while still being able to run my can (sdn-6). I’ve only found 13” and 15” handguards. Anyone make a 14” or 14.5” mlok?

SLR has a shitload of 308 handguards.  Many of them in the 13.5-14 inch range.  I would recommend going with something in the 13-13.5 inch range, as listed length may not be exact.  I'm putting together an 11.5" SBR and yet with an 11.5" barrel, the BCM MCMR-10 ("10 inch" length) is just baaarrreeely behind the shoulder for the muzzle threads.

Is there a way to figure that shit out? So a 14.7” barrel loses .625 to threads, then how much is lost to the inset I not the receiver? I thing the slr 13.7” rail might work out perfect with a 14.7” barrel.

Also I have a no silent capture buffer. Any way I could use that with an a5 carbine tube?