EDIT

I'm no engineer, but I still wonder how an extended midlength gas system on a G2 would work. Reduce the mass, reduce the gas.

G2 receivers and bcg are completely redesigned. This also eliminated the need for the longer gas tube on the G2s with standard handguards. Barrel nut and Delta assembly are also redesigned, mainly the barrel nut.

Well I just received my 14.7" Wilson combat barrel and slr gas block. I'm pretty excited that it has an intermediate length gas system. Should work great with my can. Only downside is it has a 1-11.25" twist. I'd prefer 1-10" but the price was right.

The original plan was to run this on my new Aero M5 build, but now I'm considering putting it on my current 18" Mega Maten. I'd going to run suppressed 100% of the time, and with the 14" handguard on my Maten my can should sit about 1/4" inside the handguard. It would look sweet. The only thing I dislike about the Maten is how damn heavy the thing is.

Then I would build the Aero M5 into either a 16" 6.5CM or a 12.5" .308 pistol. Decisions, decisions.

If you're not shooting 200-plus-grain loads, the 11.25 twist will serve you just fine.

14" BA Hanson 1:10 with a Sentry 7 GB and a pinned Griffin 30SD flash comp suppressor mount, built from parts from the ground up on an 80%. Measures in at 16.1 inches to the bolt face and weighs 9.5 pounds like so. The pig was a bitch to tune down to 150gr but after I got it working functions like a fucking Gauss cannon.

@762AR556
If I'm remembering correctly the G2 standardized the barrel nut with the AR15, correct? Meaning the G2 accepts AR15 rails.

AR15 "sized" handguards. But not AR15 handguards. Barrel nut is still different, it was modified to be smaller, yes, and to use standhard plastic handguards, but thats about it. Im pretty sure the delta assembly is different, or maybe its just stylized.

Like above mentioned, MI sells G2 specific stuff. I wouldnt doubt they might be the same as their AR15 with the exception of slight modification for the different barrel nut design.

Barrel nut design is not standardized between the two, but rather made similar in size I guess is a good way to put it.

I havent had much experience with the standard G2, or MOE or whatever its called. Ive only fired my buddy's a few times. Hunter model. So, going by what Ive seen online as far as parts break downs and shit.

gonna try one of these out, working on a 14.5" 308.  Got one of the BA 14.5" 308 carbine barrels on clearance (Modern series, Tactical Govt profile), and a SLR 13.5" KM Solo handguard (also on clearance), with a SF adapter brake, SLR-7 Sentry, to be mounted to an Aero M5 upper.  black.  boxing up the barrel assembly now to send it out for the P&W.  will post a pic when I get it assembled...

sort of a thread bump.

scope mounted as such to give me the right eye relief (for me), and allow for pic-rail mount brass-catcher, BUIS.


pin & weld:  meh, it is what it is, not a beauty queen for sure.  sprayed some flat black on it.

Bad idea for your stated purpose.  For a BO gun you should, IMO, be thinking about maximizing your carried ammo or minimizing its weight.  5.56 does that extremely well and .308 very poorly.
A 14.5 also pretty well needs the .308s strengths, at that size you might as well go to supersonic .300 blackout or 7.62x39, giving you nearly equivalent ballistics, lighter gun, lighter ammo, and so on.

Sort of funny story but when I first got into precision shooting I had a TRG-22 with a factory Sako brake. Went to a steel match and the guy next to me with an AI, S&B optic, and suppressor was bitching to the scorer that my rifle was too loud. I offered up o take his cab off his hands for the cost of a tax stamp. He packed up his shit and moved to the furthest open bench. Couldn’t help but chuckle....I mean it was a rifle match...

.300BO or 7.62x39 ballistics are NOTHING like a 308 with a 14.5” barrel. The 308 is literally burning twice the powder... but yeah, they’re nearly equivalent (said nobody with a chronograph, ever).

A 14.5” 308 still throws 155gr projectiles 2550fps and 110/125gr projectiles at 2700+ fps. AKs and .300BLK can not do this with these bullet weights. And the 14.5” pinned/welded 308 is going to be the same length/size as a 16” AR15 or AK so weight and ammo carried are the only hit your going to take, but you’re getting a lot more power.

The big negative imo in doing a 14.5" pinned/welded barrel is this…

suppressing a 308 rifle when you have a thread-on suppressor.  If you have a suppressor, that fits onto a proprietary muzzle adaptor, then have that muzzle adaptor pinned/welded.  Then you're good to go.   I have a 14.5" pinned/welded 556 like that.

I'll mention that using a thread-on suppressor is supposed to be more accurate and you totally bypass any problems with attaching the suppressor to a muzzle adaptor.  Some can be a real PITA.

Unfortunately for me, a 14.5" pinned/welded 308 is out of the question, since I'll want to use my thread-on can.  And making even a 12" 308 pistol seems cool, but it'd be a beotch to choot it.

Despite all the above bitching about my 308 ideas, the sweet spot for me is that thread-on 308 can with my 300blk sbr, with subsonic rounds. You can hear the round hit the dirt 100 yds away.

MUH [insert cartridge] IS NO GOOD FROM SBR!!! is what people tend to say about thses things, but they are wrong.

IIRC 10.5” 308 Guns produce more muscle energy or velocity with similar wait bullet than an AK-47 with 16 inch barrel. At least 12.5 inch barrels do it was 10.5 inch or 12.5 inch. I have a 11.5 inch 308 I am looking forward to testing out with some 125 grain ammo...

Hey by the way I am using text talk to text so may not be I spelled correctly try and reach Connecticut read it an attic please inadequate phonetically

The main reason to get into SBR 308 is if you want to hang can off the end, Since 308’s are already a little heavy, even a special light weight build tends to be a little bit farther from your body and I
A loaded magazine is a lot of weight and when you put a suppressor on the end of the  barrel really makes balance like shit.

As far as using the Thruway for a bug out gun I’m going to say no just based on how rapidly the weight of ammunition heads up. Furthermore 308 really does not have very good extra ballistics so it’s not like you have a superiority in a gun fight with me away in terms of ease of delivering to Rounds on target. Sure three-way has more penetration of barriers or whatever but you know what is that worth when you ran out of ammo because you can only carry half as much?

223 Ackley improved has area ballistics 2556 and I can still fire regular 556 or ammunition,  no I am not sure if it leads to less accuracy with regular imitation?

But if you want to short barrel 308 then he’ll get one and I’ll have to really justify it as a bug out weapon. If you’re into like a pocket to lipstick scenarios then you can easily justify 308 for defending the home against zombies or whatever all within walking distance of your 308 ammo for fort

Note that the DPM ass G to does not use the same barrels as most other 308 AR‘s so that fax and barrel would not work. Rainier arms sell some   G to pattern barrels. You can also just have the factory barrel cuts but note that the diameter of the  barrels of the gun that sort of looks like Emma force M4 may not be big enough for a muzzle shoulder and you shorten them. However some muzzle device suppressor mouse can index off of the marvel face  muzzle face.

There is a hunter model with us 16 inch barrel with mid length gas system that has a barrel that is probably sick enough to shorten and read and provide a shoulder of .740 inches diameter. Mid length gas system is compatible with 14.5 inch barrel or even shorter, no doubt about it. You can always in large the gas As necessary

text talk to text sucks.  hopefully the chinese mil intel are reading this, and it's driving their govt translators nuts.

separately, 14.5" .308 barrels are seemingly not as plentiful nowadays, used to be readily available.  So I guess that's that.

You are talking out your ass on the part about ballistics. Even short Earl 308 still are out classes either black ou you are talking out your ass on the part about ballistics. Even sure Earl 308 still are out classes  six 2 x 39 and especially 300 blackout out of similar barrel  or gun legnths

Op, I just want to say that I used to have an arm the light it had a 16 inch pencil barrel I’m in a factory job I would have that extra long ass journal for a standard front sight base and it had to carry handle and a free float tube that was not especially light light and it felt great in the hands and it’s very easy to do a lot better than that with With some of the newer hand guards that are out there and especially some of the newer receiver designs that are shorter and smaller diameter all carrier and all that four like the Xanthos receiver and a titanium bolt carrier

I reckon some humans stop getting their periods after awhile, and some just stop using them.

j/k

I’ll ignore the questionable grammar and the ad hominem attack and just provide data.
A 14.5” .308 will throw a 150gr slug at about 2450fps.  It will also have brutal muzzle blast, and the ammo load out will be about 2/3 what it could be for the intermediate .30s weight for weight.  It will be about two pounds heavier than a .300BO.
A 16” 7.62x39 or .300BO will throw a 125gr slug at about 2350-2400.  The rifle will be about two pounds lighter, will be far easier to shoot rapidly, and the ammo load greater by 1/3 or lighter by 1/3.
So yes, I stand by my opinion that at 14.5” the .308 gives up too many of its advantages while retaining its disadvantages, namely ammo and rifle mass.

If you compared apples to apples, a 14.5” 308 would shoot a 125gr around 2700fps.  That’s certainly more than either the 7.62x39 or 300BO.  Also sticking with 308 makes finding other ammo much more possible in a shtf scenario, as the OP is referring to.   But also in that secenario, the 5.56 makes even more sense all around.

Disingenuous... AT BEST.

Why not compare the (weak ass) 150gr numbers from the 14.5" .308 to a similar 150gr load from a .300blk ?
Federal AE 150gr 300blk - 1900FPS & 1200 FT-LBS ... that's pitiful. Even from a gun that's 2 pounds lighter.
The 308 is about 30% faster and has 67% more energy shooting the same bullet. That's significant.

Nevermind that ACTUAL velocity numbers for that bullet is faster than "2450".  
Mine will shoot 155gr TAP 2500+ FPS depending on temps. And it only weighs in at 8LB without optics.

Because the 125 grain is a typical load for the 7.62x39 and .300BO just like the 147 is a typical load for the .308.  There's no real reason to go heavier in .300 if you aren't suppressing, and for 7.62x39 the vast majority of loads will in fact be the 125.  And this isn't even getting into 5.56 which pays yet further dividends in weight reduction for the rifle and ammo.
Sure, your .308 can weigh 8#.  It's also easy enough to build a 6# .300 or 5.56.

It is fair ebough to compare 125 g 308 load vs 123/125g loads in x39 or BO as the lighter loads are more efficient in short 308 barrels.  14.5 308 has way more powah than a x39 and better external ballistics as well as being more mechanically accurate.  And an AK is not light or well balanced w those long ass receivers.  It is not that hard or expensive anymore to have a 308 AR under 8lbs, mine is under 6 lbs, though it is 11.5”.   Looks like standard AK is 7.7 lbs sans magazine

If you are gonna go to an ar15 envelope, well there are alot of options.  But 300 BO is weak compared even to x39

I don't think 7.62x39 is an optimal choice because, as you said, AKs tend to be heavy (7.5-8#) and 7.62x39 ARs are not fully trusted for a variety of (somewhat arguable) reasons to do with reliability and durability.  Another 5 years of product development and they may be.  On the other hand another 5 years may see the end of cheap ammo and the effective end of the cartridge compared to .300 or 5.56.
A hot .300 BO is the 7.62 equivalent for the AR and has advantages if you're using true intermediate-level loadings vs a nerfed.308.  But to be clear my choice for a bug out rifle would be none of those, it would be a 16" midlength 5.56 AR for rifle weight and ammo load out which would be, all told, multiple pounds ahead  other choices.

If built right, it’s awesome. I love my 14.5” .308.
Current setup:
Attached File

When I think bugout, I think fighting your way to the hills where you'll have to sustain. Not room clearing and close encounters while staying local.

Let's be real. In a bugout scenario 300BLK will be as common as bottled water in the Sahara. 5.56 and 308 are two of the most common military and civilian calibers, with one having a distinct advantage for protecting and providing. AK's are heavier than modern 308 AR's too.

A short 5.56 has more concussion than a 308 carbine. I've long wondered if people who talk about 308 muzzle management have trigger time on a 308 AR. If you're used to offset bore axis rifles like the M14 or 91, yeah it has an impact. My experience with 308 AR's is a totally different ballgame though.

I disagree wholeheartedly. My 14.5” 308’s concussion and blast is in a whole other league compared to my 5.56mm SBR. Not even comparable. You can feel it in your teeth and chest and it vibrates videotaping cameras 5 feet away. Makes shooting the 11.5” 5.56 seem like a 22wmr.

Then again, my 308 has an AAC brake on it and the 5.56mm has a Blackout hider.

I concur.

My 20" AR10 with BCM brake was loud as fuck. Didnt do what it says its designed to do. Would set off car alarms in range parking lots. 556 with brakes, 2 port style, etc etc, were NOTHING compared to the AR10.

Teeth shaking is an understatement.

My old 18" MaTen with Griffin flash/comp was teeth rattling as well. My dumbass shot 20rds with no ear pro. Only damaged the left ear and its fully healed accordingly to hearing tests I took for work while back.

I do agree, 556, 308, 3006, 30-30, are calibers of choice when it comes to SHTF.

Even the people I know that dont shoot or hunt, have their dad's or grandpa's 3006 or 30-30 lever. And a few boxes of ammo. Thats what does it for me. Sure, marketing will tell you 6.5C and 6.5G are the next big thing. Sure, you can find those at walmart right now, but you wont find many people who have them. Even if 10k people had them and were stacked here in Houston, what are the odds you will run into them? Slim the fucking none in my eyes. Yeah, they might have 10k rounds between them, but dont mean shit if they are mixed in with 12million fucking whackos trying to steal your shit and eat your food. That number would drop dramatically in first few months, but surviving that first few months is the key.

Gotta stop here or Ill go off on a tangent. I can talk this shit until the end of time.

And the reasoning behind this statement?

Eta; Would 10.5 be any better than 12.5?

Substantially. However, it still wouldn't be as good as 8.5.

So 10.5>12.5?

Aero M5, BA 14.5 barrel, SLR rail & adj GB, Aero nitride BCG, PA 1-8X.

Got an Aero lower and trying to decide what to do with it...  in olden times, pre 2000, a 16" 308 was considered ridiculous muzzle blast...

I already have 10.5 7.62x39 upper, any point trying to do an AR10 shorter than 16" or not?  I have a SDN6 and could maybe do 14.5 with perma attached mount, but unsure how the SDN6 would stand up to that.  Also have a thread on Sandman Ti, could run that on a pistol AR10.   Not really feeling like this project is stamp worthy.   And I have a first gen UBR just laying around.

Yes. 14.5" 308 still beats the pants off even a full-size x39, let alone a 10.5 inch x39. If you feed it similar weight bullets (120-125gr bullets) it's easy to see its WAY faster. But it's a .308 so feed it 155gr Amax bullets and it will still fragment a LONG way further than any 5.56mm/5.45mm/7.61x39 full length rifle will.

I have a 14.5" with a pinned 51T brake along with both a 762-SDN-6 a newer generation 762-SD. Neither one is "quiet" on a 14.5" 308, but it's pretty tame with both. It won't ring your ears so I don't use earpro usually with it- although I don't know that it's considered "OSHAA safe" either. I don't have a "favorite" can for it as the SD is quieter, but the N6 is noticeably more handy and only a tad louder. If I had to bug out with it, I think I'd take the N6. The 14.5" brake is pretty brutal without the cans though.

If it matters the 762SDN6 and the 762SD are rated down to 14.5" for .308win, 10" for 5.56mm, and 7.5" for .300BLK.

I've got a previously painted Aero M5 upper I'd sell you cheap if you want to move forward with the project.