Aero Precision M5 Build Questions

[ChuckP65]

I am about to build my M5. I bought the Aero nitrided bolt and a PRS stock. This is all about precision not banging 100 yard gongs.

Questions - Should I go 6.5 or 308? Is there an issue gassing for a 6.5? Does it feed 6.5 ammo like ELDs and MKs well? What 'adjustable' gas block is best for the Atlas handguard? Most importantly the barrel. I had great luck with an Odin Works for my 15 build. They stock 6.5 @ 22 inches. Not settled on buying from them though. What have people who build this in to a precision rifle platform used? Thanks!

 

[Ravenworks]

You need to decide a lot of things about what you want to do before picking a caliber.
Not to sound like a dick,but how much time have you spent researching this?

 

[ChuckP65]

You need to decide a lot of things about what you want to do before picking a caliber.
Not to sound like a dick,but how much time have you spent researching this?

I didn't keep track. I thought this was part of the research. I shoot a ton of bolt LRP and decided to build an SA to also use. The bolt is 6.5 and I wanted to know if it made sense to go in that direction mainly because of the obvious and because 6.5 doesn't come in FMJ. I've read on it for weeks but as you are aware there are a lot of opinions on just about everything. What are all of the things I should be deciding? BTW Thanks for the help.

 

[Ravenworks]

You will save yourself a bunch of problems if you stick with all Aero precision parts.
That right there will be 90% of making you rifle works.
Creition Hybrid barrels are pretty hard to beat.

 

[ChuckP65]

Thanks for the advice. Much appreciated. I did buy much of the mechanicals from AP. I 'thought' they made one of the better if not best DIY 308s. I'll figure it out and hope it's a nice build.

 

[bfoosh006]

IMHO...

6.5CM for precision and the improved ballistics.

308 for good distance and ample variety of ammo choices.

Gassing wise, most all Large Frame AR's seem to have ample gas, An Adj. GB is a great way to limit its flow as desired.
FWIW , of all the barrels I have tried in 308 and 6.5CM , only the Kreiger had a "small" gas port size.

I think Odin includes a free Adj. GB with the purchase of their GTG barrel... you might see if it would fit, with ample room to spare.

You may or may not benefit from some simple polishing of feed ramps and the feed lug areas.... I don't mind tinkering if it saves me some money.. and polishing feed ramps is not a biggy.

I would consider lapping the upper receiver and Loctiting the barrel in place... not everyone thinks it is "valuable" for precision... but so far I have seen precision improvements on every AR I have assm.d.

Criterion barrels even recommends it.

 

[AMGtuned]

I run the enhanced, and quantum, handguards from Aero. They are cavernous inside. The Atlas, I'm pretty sure, is much slimmer inside. Make sure you consider that when choosing barrel profile, and gas block size. If you're stuck on the Atlas

 

[Gatorshark]

If you reload, or will in the future, go creed.
If you plan to go long range, go creed.
If you want to shoot all day without jarring your teeth loose, go creed.

 

[Zak2006]

I posted my recent aero 308 build in the 308 AR10 Build/Info/Picture Thread. I can’t comment yet on how it shoots yet unfortunately but everything fit together extremely well with zero issues. May give you some ideas for compatible parts. ?

 

[2aBaC̶a̶]

Switched my 308 over to 6.5cm by simply swapping barrels.

Just do it.

Either way you may need to tweak something. An adjustable gas block helps fine tune things. Also doesnt hurt to get a couple different buffers.

 

[Mechdesigner]

I built my 6.5 M5E1 using a standard aero non adjustable gas block and the normal rifle buffer and A2 style buffer tube. Feeds everything perfectly no problems at all. I did use the premium Ballistic advantage barrel set up to work well the M5E1. Produces .5” - .75” groups consistently

 

[brian47374]

I shot .308 for years. But, i i switched to 6.5cm last year and it was a great move. IMHO 6.5cm is a better round for longer distances. You will find the diehard. 308 crowd... but i feel like I'm cheating with my 6.5cm. Also, I'm shooting factory ammo with great results. I couldn't be happier with my M5 build.

 

[DocRDS]

If you reload, or will in the future, go creed.
If you plan to go long range, go creed.
If you want to shoot all day without jarring your teeth loose, go creed.

Wussy!

WIth that out of the way, as an old 308 die hard there really isn't a downside to 6.5CM, I've been looking for a cheap way to switch to 6.5 myself.

Who am I kidding, i am just going to buy another large AR... (in 6.5)

 

[rulellis]

If you’re building your own, pick what you think you want and it’ll be easy to change the barrel with little else if you change your mind. It’s hard to beat the creedmoors starting out. I just built one with aero upper and lower in 6 creedmoor. I used a Wilson Combat barrel and slr sentry 7 adj gas block.

 

[The Muffin Man]

Barrels are fairly subjective and by that it all depends on what sort of budget you are working with. If your looking for long range precision the barrel is the last think I would try to pinch a few pennies on so I would probably look at getting a Bartlein custom spun from anyone of the reputable companies such as Craddock Precision. Alternatively if that's not in the budget you could get a Criterion for a little less and you could look at someone like Fulton armory or buy one from retail. I'm probably going to go with a Proof Stainless for my build simply because I want to try them out and their pricing will be right between Criterion and a custom spun Bartlein plus you can get the +2 gas system.

 

[Trigger Monkey]

because 6.5 doesn't come in FMJ.

Sellier and Bellot makes a 6.5CM 140 FMJ round

Winchester also has a 6.5CM target ammo in their USA Ready Line, it's a 125gr flat base open tip bullet. It's not bad to 500.

 

[flyer]

You will save yourself a bunch of problems if you stick with all Aero precision parts.
That right there will be 90% of making you rifle works.
Creition Hybrid barrels are pretty hard to beat.

I disagree with staying all Aero.

I really like some parts of the M5E1 setup but not all.

I like the enhanced upper, matching handguard, the lower receiver and partial LPK.

The rest I buy from other places for either better parts or lower cost.

I can buy a Toolcraft NiB BCG for less than a plain Aero BCG. Aero's barrels are ok but other brands have better reputation for accuracy. If you go for a carbine stock, the AR10 style recoil buffer setup is better than Aero's LR308 shorty buffer setup. I usually buy my buffer setup from POF.

If you are going for accuracy, you should reload and then an adjustable gas block is a really good idea. I don't think Aero makes one.

Likewise, an accurate AR needs a match trigger. I don't think Aero makes one of them either.

I even change out some of the partial LPK. Aero seems to use an AR15 style magazine release. There are some made for large frame ARs with a longer stud and the actual latch sticks out more to retain the magazine better.

I also like a charging handle made by Mega and some little upgrades from Strike Industries.

I stop short of making mine a "Gucci" AR but I get the most important features and upgrades for only a little more than staying all Aero.

Another thing is that mixing it up let's you balance your build more toward your intended purpose. Aero just does not have the same amount of choice as looking at the entire market of LR308 compatible parts.

 

[I SHOOT]

I am about to build my M5. I bought the Aero nitrided bolt and a PRS stock. This is all about precision not banging 100 yard gongs.

Questions - Should I go 6.5 or 308? Is there an issue gassing for a 6.5? Does it feed 6.5 ammo like ELDs and MKs well? What 'adjustable' gas block is best for the Atlas handguard? Most importantly the barrel. I had great luck with an Odin Works for my 15 build. They stock 6.5 @ 22 inches. Not settled on buying from them though. What have people who build this in to a precision rifle platform used? Thanks!

Like others have said buy the lower parts kit from AERO
Or at a minimum the take down pins
As for caliber mines a 308 krieger barrel.
The 65s I've messed with are a bit gassy
But with a good adjustable gas block you can tune them just fine im a fan of the SLR rifleworks
Good luck!

 

[Shortbus6588]

+1 on staying all aero/ ballistic advantage on the build for reliability and accuracy. I have two Aero M5 rifles, one E1 upper and one plain. Both wear ballistic advantage/ aero barrels and both are accurate and consistent for a gasser. Ballistic advantage has a 1moa guarantee on their barrels, my sample size of two definitely will perform to that standard. The only mechanical part I and would change is the trigger to one of your liking, mil-spec is not great for precision.

Cheers

 

[BenW]

I recommend getting a matching bolt with whatever barrel you choose. Headspace on large frame AR’s aren’t as consistent as AR15‘s. I’ve been happy with my SLR rifleworks clamp on adjustable gas block. The Aero Atlas handguards are definitely very large in diameter, inside and out.

 

[Trigger Monkey]

The ATLAS S-One and R-One have an inside diameter of 1.5", this is for the M5 version.

 

[Randy_Lahey]

Didn’t read all replies but owning both .308 and 6.5 creedmoor I prefer the 6.5 1,000%.

140eld-m shoots light out. Never had feed issues. Only issues I had was gas related and solved with superlative arms gas block and spacing issues with buffer tube/buffer. I’ve not had great
Luck accuracy wise with .308 but that could be many variables. Two of my 6.5 creedmoor shoot exceptionally though.
Just my 2 cents

edit: my barrels are PSA so that factors in but my 6.5’s shoot 1/2-3/4 moa or less EASY!!! Getting moa out of the .308 is a struggle

 

[Ravenworks]

I disagree with staying all Aero.

I really like some parts of the M5E1 setup but not all.

I like the enhanced upper, matching handguard, the lower receiver and partial LPK.

The rest I buy from other places for either better parts or lower cost.

I can buy a Toolcraft NiB BCG for less than a plain Aero BCG. Aero's barrels are ok but other brands have better reputation for accuracy. If you go for a carbine stock, the AR10 style recoil buffer setup is better than Aero's LR308 shorty buffer setup. I usually buy my buffer setup from POF.

If you are going for accuracy, you should reload and then an adjustable gas block is a really good idea. I don't think Aero makes one.

Likewise, an accurate AR needs a match trigger. I don't think Aero makes one of them either.

I even change out some of the partial LPK. Aero seems to use an AR15 style magazine release. There are some made for large frame ARs with a longer stud and the actual latch sticks out more to retain the magazine better.

I also like a charging handle made by Mega and some little upgrades from Strike Industries.

I stop short of making mine a "Gucci" AR but I get the most important features and upgrades for only a little more than staying all Aero.

Another thing is that mixing it up let's you balance your build more toward your intended purpose. Aero just does not have the same amount of choice as looking at the entire market of LR308 compatible parts.

Let me restate what I meant

If you are buying the M5E, then buy their parts kit, their buffer kit and their hand guard.

The rest depends upon what else you are mixing and matching.
Don't go cheap or you'll regret it.

 

[flyer]

Aero's carbine buffer kit is dumb. They just copied the DPMS LR308 setup and it was dumb when DPMS did it.

The LR308 and Aero buffers are shorty buffers. They are uncommon and harder to make heavy buffers since they are short.

The AR10 carbine design extended the buffer tube instead of cutting down the buffer so it can use standard AR15 buffers along with H1, H2 and H3 buffers which are more common than standard weight LR308 style shorty buffers.

You can tune an AR with buffer weight so making it use common buffers is a lot better than making it use a common buffer tube.

And it's not like the AR10 length buffer tube is uncommon, POF makes a nice one, Vltor makes a very nice one, Armalite makes a nice one and PSA makes a cheap one. For a part you buy once, install and never change, that's plenty of sources.

On to handguard diameter. A large frame AR makes the most sense as an accurate long range shooter, not a short barrel carbine to carry around. I don't mind a largish handguard on that type of rifle. As long as you don't get a quad rail that needs rail covers, the Aero handguards made for the M5E1 upper are fine. Barrel nut mounted skinny rails on conventional male threaded uppers are a lot more likely to flex the upper receiver if you sling up tight or load a bipod so I like the Aero enhanced setup to avoid POI shift.

 

[aaronk]

See my Aero build here:

https://www.snipershide.com/shooting/threads/my-1-2moa-ar10-build.6972093/

I won't comment on the caliber, personal preference there...

I'll say I think my buffer/BCG combo is a little too heavy though. My gas block is all the way open and it doesn't lock back on an empty mag. I wasn't expecting that with a rifle length gas system with the .308 platform.

 

[Larmo]

+1 on Aero/Ballistic parts. Got a ballistic 18 inch stainless premium rifle length gas in 308 and ballistic bcg. M5E1 upper with enhanced handguard. Had it out to 906yds so far. I have a thread with a picture, build sheet, and initial impressions in the Semi Auto forum.

 

[SniperEnvy]

If you buy a completed upper make sure you check the barrel and that it is dimpled for the gas block. I bought a 308 upper a few years ago and it turned into a bolt action repeater after about 300 rounds. Turns out the gas block loosened up and it wasn't dimpled.

 

[D1gger]

If you do it right, you should have a sub MOA gun in either caliber.
To answer your original question, if it's about accuracy at range, your answer should be pretty simple. Enter both into a ballistic calculator and start punching in ranges. The 6.5 just wins at distance. I shoot both and love the 308 but facts are facts.
If you don't reload and factory ammo choices are a factor, then I think the 308 has a slight advantage, for now. With the US military starting to use 6.5 now, more choices might become available in the 6.5 in the future

 

[AMP!]

Go 6.5 CM, Aero is a great base but the accuracy will come from the barrel, BCG, recoil system and trigger IMO. I’m not expert, but my Aero build with a JP BCG and SCS (full mass) and Geissele trigger is a half MOA gun if I do my part shooting 143s or 147s.

 

[DocRDS]

Aero's carbine buffer kit is dumb. They just copied the DPMS LR308 setup and it was dumb when DPMS did it.

The LR308 and Aero buffers are shorty buffers. They are uncommon and harder to make heavy buffers since they are short.

The AR10 carbine design extended the buffer tube instead of cutting down the buffer so it can use standard AR15 buffers along with H1, H2 and H3 buffers which are more common than standard weight LR308 style shorty buffers.

You can tune an AR with buffer weight so making it use common buffers is a lot better than making it use a common buffer tube.

And it's not like the AR10 length buffer tube is uncommon, POF makes a nice one, Vltor makes a very nice one, Armalite makes a nice one and PSA makes a cheap one. For a part you buy once, install and never change, that's plenty of sources.

On to handguard diameter. A large frame AR makes the most sense as an accurate long range shooter, not a short barrel carbine to carry around. I don't mind a largish handguard on that type of rifle. As long as you don't get a quad rail that needs rail covers, the Aero handguards made for the M5E1 upper are fine. Barrel nut mounted skinny rails on conventional male threaded uppers are a lot more likely to flex the upper receiver if you sling up tight or load a bipod so I like the Aero enhanced setup to avoid POI shift.

When you say AR10--you are refering to armalite? I may have to take a look at adjusting mine (It's DPMS) as I am putting on a PRS Stock so the tube is getting chucked anyway.

 

[flyer]

I hesitate to say Armalite and AR10 in the same sentence because the company that calls itself Armalite today is not the same as the Armalite that designed the original AR10 and the AR10 they sell today is not the same as the AR10 that Armalite designed.

With that said, I believe the "carbine stock" we see today is an invention by Colt or old Armalite for the AR15 and when that concept was transferred to large frame ARs, two types emerged. The shorty buffer type was favored by DPMS and a few others. Armalite (the present day version) did it with a long buffer tube and AR15 type buffers.

I prefer the LR308 type of large frame AR because DPMS didn't stop anyone from making compatible parts. "Armalite" was much more proprietary and expensive but not necessarily better except for their carbine buffer setup.

A number of companies used the same idea, the POF P308 setup is the same, Vltor's A5 buffer tube is the same length and they also sell it with different markings for large frame ARs, even PSA used the setup on some PA10s. I think there are more but that is what comes to mind. I like the POF P308 buffer tube kit because the tube is nicely made (on par with Vltor in my opinion), the correct spring is included and POF runs sales for 10-15% off on occasion.

 

[WoobieJ]

I am about to build my M5. I bought the Aero nitrided bolt and a PRS stock. This is all about precision not banging 100 yard gongs.

Questions - Should I go 6.5 or 308? Is there an issue gassing for a 6.5? Does it feed 6.5 ammo like ELDs and MKs well? What 'adjustable' gas block is best for the Atlas handguard? Most importantly the barrel. I had great luck with an Odin Works for my 15 build. They stock 6.5 @ 22 inches. Not settled on buying from them though. What have people who build this in to a precision rifle platform used? Thanks!

Aero precision + proof camgas + JP parts and adjustable gas

rifle length buffer tube and a Precision stock would be good additions. HiSpeed NM match trigger also.

 

[brian47374]

If you don't reload and factory ammo choices are a factor, then I think the 308 has a slight advantage, for now. With the US military starting to use 6.5 now, more choices might become available in the 6.5 in the future

Im using hornady 140 eldm 6.5cm and im getting at 10fps sd which is really amazing for factory ammo. Im not sure to what advantage. 308 factory ammo has that 6.5cm doesn't.

 

[flyer]

I agree, while 308 might have more choices, I don't think many would be "better" than their equivalent in 6.5 Creedmoor.

Also, 6.5 Creedmoor is getting so popular that the choices at my LGS are about even.

Also, if you can find or order Berger 140 grain, it has a Berger bullet and Lapua SRP brass at a very reasonable price. I don't think you can get a premium bullet and Lapua brass in .308 unless you pay a lot more than something like FGMM.

 

[D1gger]

Im using hornady 140 eldm 6.5cm and im getting at 10fps sd which is really amazing for factory ammo. Im not sure to what advantage. 308 factory ammo has that 6.5cm doesn't.

I was referring mainly to availability and price. In my area, comparable 6.5CM is slightly more expensive than 308.
Those are pretty awesome SD's. In the same ammo in my rifle, the best I could get was 15. Still not bad for factory.