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20” Aero M5 build, have some questions

Bhobbs

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Minuteman
Jun 13, 2011
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I picked up an Aero M5 receiver set to start a .308 build. My plan is for a 20” rifle for the range. Probably will run 155 to 175 grain bullets. Most ranges around here are 2-300 yards but I can shoot further on public land, so maybe 1000 yards. So far, I have an assembled M5 upper, stripped M5 lower, rifle length buffer kit and a lower parts kit minus the trigger. I plan on getting a PRS stock, to help balance the longer barrel and I like the stock in general.

What brands for a barrel, BCG and trigger should I be looking at?
 
I ran Aero upper/lower, Lothar-Walther, with Toolkraft BCG. RLGS, rifle buffer +1 tungsten weight. Had 0 issues.
 
i use both the Aero nitride, and the Brownells nitride BCGs. they're both HP, and the Brownells have always headspaced well, and the Aero as well, but that's to be expected. I like the Geiselle triggers (personal preference), and use the HS-NM for my precision guns (very pricey, wait for Black Friday sales).

I would echo the comment above by Tucky Bill: Criterion, or a Compass Lake barrel whatever you could afford.

if you're planning on reaching out to 1,000yds, you might want to consider a 20MOA or even 40MOA scope mount. I use the ADM Recon-S with built-in 40MOA for my 6.5CM, aspiring to 1,500yds.

40 MOA = 11.6 mrads
https://www.justintools.com/unit-conversion/angle.php?k1=minute-of-arc&k2=milliradians

also, I recommend you get a First Focal Plane (FFP) scope at the outset.
 
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Don’t overlook Proof stainless barrels. They are cut rifled and hand lapped. They are also usually in stock at midwayusa etc for about $500. I have heard/read that they hammer. I also thought this was an interesting article. I would attach it but I am not computer savvy. It’s from precision rifle blog .com
C6EAD15D-2F6C-4A1A-AE45-FAE7004676D0.jpeg
 
You have stated your intended use, but no budget. The parts you need range wildly in price...
 
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Another vote here on LaRue triggers which are on par if not better than the Billy Guys-lee triggers. And another vote on Proof barrels but if you have some extra scratch Id also consider one of the AR10 drop ins that Lilja has like the 740 drop in. Lilja barrels are spooky accurate even for someone who has no fucking clue (me).

Youll also need quality glass if you dont have it already. Obviously.
 
I'm using a using a blemished Rubber City BCG with 21" Lothar barrel w/rifle length gas tube and adjustable gas block. Larue trigger.
Everything worked with no fussing, just set the gas block. I was actually surprised as I was expecting the worst.
 
My go-to is almost always criterion for barrels, I’d run an SSA-E, and the full mass JP BCG with HP bolt is the slickest thing I’ve ever had my hands on.
 
I signed up for alerts when the Criterion Hybrid 20” is back in stock. Is it worth getting the matched Fulton bolt carrier or should I get another brand and just check head space?
 
I signed up for alerts when the Criterion Hybrid 20” is back in stock. Is it worth getting the matched Fulton bolt carrier or should I get another brand and just check head space?
depends on your budget, and do you already have the headspace gauges?
 
Ranier Arms Ultra Match. They have a great guarantee.
I have one of these in a 22" 6.5 Creedmoor in my Aero build and have been very happy with it. Great bang for the buck at less than $500: fluted, +2 gas system, reportedly Craddock built Criterion blanks.

I run mine with an Aero BCG, a KAK 9.3 oz buffer and tubb spring in a PRS Gen 3 Stock. With a Superlative Arms adjustable gas block it shoots very soft and runs like a sewing machine, even with a Nomad-30 hanging off the end. Geissele National Match trigger in it is awesome. I have a Larue MBT in another gun, and it was over $100 cheaper, but for a precision gun I find it nowhere near as nice as the NM with the light springs.
My friends commented on how soft it shoots and my kid loves shooting it too. Sub moa with Hornady 140gr HPBTs and 1K hits on steel were pretty easy.

She's a heavy girl though. But that's kind of to be expected for this style gun.

Finding a 16"+ handguard that covers the gas block can be a little bit of a challenge, but if you don't mind it exposed, 15" Aero's should be good to go.
 
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What is your budget for a barrel? I'd check out toolcraft for a BCG or Areo. As far as a barrel if I didn't want to spend a lot, I'd look into criterion. However, I haven't seen any in stock in some time. Fulton armory has some criterions in stock. Maybe check them out. I personally like CMC match triggers with 2.5 lbs pull. I pretty much have my build complete, but contemplating on a barrel same as you. I'm between Fulton criterion and a Rainer arms barrel ultra match mod 2 which I also believe is a criterion blank. Just a different contour.
 
I use Lother Walther for large frames and I've had very good luck with them. One of the barrels I had rivaled my bolt gun for the first 3500 rounds or so.
 
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Another vote here for Criterion M118LR Hybrid barrels. I am running a 20” in an Aero M5 build, and it’s fantastic.

Might also look into JP Silent Capture Spring system.
 
stick with aero or toolcraft bcg and the larue is hard to beat but criterion has their 2 stage which is nice (really just a schmidt 2 stage which is same as aero's).

barrel really depends on what you're going for. If accuracy, get the best you can. If plinking and fun, kak value line will get you moa cheap
 
Upper, lower, LPK, trigger, stock, hand guard and barrel nut come out to about 1,000. I think 700 to 800 for the barrel and BCG would be reasonable.
 
I have a similar setup. Running Aero M5 receivers, Geissele SSA-E, Magpul PRS stock, JP SCS, and JP LMOS. I've tried quite a few barrels for AR10s: Ballistic Advantage, Criterion, Proof, and a Bartlein from Craddock Precision.

Proof has the superior accuracy BUT it' a 24-inch stainless steel barrel in 6.5 Creedmoor. It prints tiny groups on paper and easy hits on 1 MOA steel out to 700 yards. I won't ever use Ballistic Advantage again on a large frame gas gun due to their barrels being quite inconsistent and unable to hold 1 MOA. At one point I had a 24-inch Criterion in .308 that was a good shooter, I can't remember why I sold it but the Criterion is the only budgetary barrel to consider. The Craddock Precision Bartlein is also an excellent barrel, but expensive. It shoots well, prints sub-minute groups on paper and I've taken it out to almost 800 yards. Mine is a 20" bull barrel - not really competitive in a match setting but a lot of fun to shoot.

I've burned through a lot of money getting my AR10 to shoot tiny groups and hold accuracy at longer range and all paths lead me to just buy the more expensive components. In hindsight, it would've been cheaper to just buy a JP or GAP10 from the start :ROFLMAO:
 
Hard to beat this. They are awesome..HP bolt, love their coating.. read the description....may have cosmetic laser engraving blemish only. Fully functional and still has their lifetime warranty. Also if you read the description, you can put in the order notes you want them to put their adjustable gas key on it! Boom...no need for adjustable gas block. I love their AGK.


Don't sleep on these Wilson Combat barrels in your budget range...they flat out shoot.
With above BCG and below barrel you have money left in your budget to grab a Geissele or MBT... $515

18" Super Sniper is in stock....20" is out of stock

 
My above budget included a Larue MBT-2S. I have an SSA-E I am putting in an SPRish AR15 build but I don’t have any trigger time with it. A lot of people recommended the MBT, so I figured it was worth checking out for the price.
 
Cool, thanks for the heads up. I’m in no rush so I can wait for it to show up.


And I couldn't find a cosmetic blem on ANY of the blems I bought from them. Looked exactly like all the non-blems I've bought from them. Same packaging, everything.
 
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And I couldn't find a cosmetic blem on ANY of the blems I bought from them. Looked exactly like all the non-blems I've bought from them. Same packaging, everything.

Man, you weren’t kidding. I just got the shipping notification from RCA.
 
"What brands for a barrel, BCG and trigger should I be looking at?"

I have also had great results with Criterion barrels.
I admit I am also very intrigued with Lothar Walther barrels.
Buy the best barrel you can afford.
You will spend more money on ammo, trying to make a lesser brand barrel shoot to your desired expectations.
Money that should have been spent on a better barrel.
IMHO, barrels are a highly under rated bargain, given the current cost of match ammo and your time / effort.

That said.... consider an Adj GB as well... I use SLR's since they are very linear in the adjustments.
Out of all the numerous brand 308 / 6.5CM barrels I have, only the Krieger has a reasonable sized gas port size.... all the others have benefited from a Adj. GB.
MAKE sure if you buy a Adj. GB it fully clears any handguard... any close contact with a handguard can result in less than consistent ,crap groups

And FWIW... the LaRue trigger is a great bargain, but I really don't like the "sharp" less rounded edges on the trigger shoe.
I know that is fussy sounding.. but..
The LaRue , if it had a USGI rounded trigger face , I would love it. So I guess I am just mentioning the trigger face thing, in case you haven't felt it.
However.. I still own 4 of them.

BCG wise... have had great results with ToolCraft, Aero, and for suppressed the CMC / SanTan enhanced 308 BCG , the third exhaust port , with the DPMS length gas tube is certainly noticeably softer shooting.... hmm .. I need to try it in the smaller gas port Krieger.

Just my 2 cents.

I also suggest lapping your upper receiver face, and shimming / Loctiting in the barrel. YMMV , but it has always worked for me.

Also, I prefer a snug upper to lower fit, it makes your wielding of the AR more consistent.
 
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I grabbed a Rubber City blem BCG. I’m pretty settled in a Criterion hybrid nitrated barrel. I do plan on lapping and bedding the barrel, just need to read up more on bedding. I can’t decide which trigger to go with. I’ve used the SSA-E and like it but it seems the MBT-2S is more or less equivalent but half the price.
 
I have 2 built Aero M5's. They have been pretty solid.

I have a Rainier (6.5 Creedmoor) Ultramatch barrel and it has been great (a lot of rounds through it). I have a Proof on my other 6.5 and it has been great too so far (only have minimum rounds on it, just mounted recently).

308 you may be able to use a standard BCG. Aero and Toolcraft. I have a Toolcraft with a JP HP bolt in one. I just put a RCA HP (Multicaliber) in the other. Pricey, but seems nice. I will be seeing how it does tomorrow probably.

Triggers are mostly preference. I have had RRA Match, KAC (2 Stage match), Elftman Match, CMC 2+2, Triggertech, AR Gold, Giessele SSA-E, SD-E and HSNM and LaRue MBT's. Decided to try out as many as I could and find what I liked. I actually bought 4 LaRue's when they came out thinking I would standardize on them from the reports. The AR10's are Gieselle HSNM and AR15 are AR Gold's.

The HSNM and AR Golds are the only triggers I have kept on my Rifles. The Elftman and Triggertech were nice triggers too. I still have a LaRue MBT, but it sits in a parts box. The other 3 were sold off pretty quick after trying the first one. Probably would have sold it, but I don't have the packaging anymore so parts box is where it'll live. Only time I use it is if I have a build that is only missing a trigger. It'll go in while I wait for something else.

I know I will probably get backlash for this... but the MBT is a decent trigger for $99. If it was any higher in price I would pass it over. It's not on the level of the others mentioned.
 
So, I’ve been patiently waiting for the Criterion barrel to come back in stock but I’ve heard it may be many months out, even up to a year. Is this true?

Also, I figured it would be time to start looking into optics. The best scope I currently have is a Vortext PST 6-24 on my Remington 700 .30-06. I like it so far but wouldn’t be opposed to spending a little more if I could get a better scope. I don’t have a ton of experience with optics, so I’m open to anything. Any recommendations?
 
So, I’ve been patiently waiting for the Criterion barrel to come back in stock but I’ve heard it may be many months out, even up to a year. Is this true?
I've gotten a few of my Criterion barrels from Brownell's, in-stock, and occasionally from Fulton Armory, in-stock.

I think the estimates for wait-times posted on the Criterion web-page for a specific barrel are reasonable ball-park estimates, i.e. if it says 3-4 months, I doubt it's a year. and if there's no estimate, then who knows.
 
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I've gotten a few of my Criterion barrels from Brownell's, in-stock, and occasionally from Fulton Armory, in-stock.

I think the estimates for wait-times posted on the Criterion web-page for a specific barrel are reasonable ball-park estimates, i.e. if it says 3-4 months, I doubt it's a year. and if there's no estimate, then who knows.

I didn’t see any wait times on the Criterion site. I’ll have to check again.
 
Hard to beat this. They are awesome..HP bolt, love their coating.. read the description....may have cosmetic laser engraving blemish only. Fully functional and still has their lifetime warranty. Also if you read the description, you can put in the order notes you want them to put their adjustable gas key on it! Boom...no need for adjustable gas block. I love their AGK.


Don't sleep on these Wilson Combat barrels in your budget range...they flat out shoot.
With above BCG and below barrel you have money left in your budget to grab a Geissele or MBT... $515

18" Super Sniper is in stock....20" is out of stock

I have only heard good things about the Wilson combat super snipers. I bought the 20" fluted for my 308 and paired it with their bcg. Hopefully it's a shooter, haven't tried it out yet.
 
So the Wilson Combat 20” is back in stock. Not sure if it’s worth waiting indefinitely for the Criterion or grabbing the Wilson Combat.
 
I am putting together another M5 also! If you want to save some cash in the trigger, Schmid Tool makes a NIB two stage that I enjoy and a few other companies pick them for OEM parts, with all the barrel recommendations I might pick up a Wilson combat instead of Ballistic Advantage now lol.

Also Forward Controls has a nice selection of small parts for your lower if that falls in your veiw of interest.
 
Wilson makes a nice barrel. I wish mine on my 6mm Creedmoor would have worked. I could not get it to run without piercing primers. Even with an adjustable gas block and tuned buffer it would pierce primers with loads at the bottom of the charge tables. This was using standard and HP bolts.

The barrel itself is nicely done. The finish and workmanship are outstanding. I still have it. Maybe one day I will put together another upper and see about messing with it more. For now it was replace with a Proof Carbon barrel in 6.5 Creedmoor. Works great but I really didnt need another 6.5.
 
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I haven’t decided yet. Most people recommend the Criterion over the Wilson Combat. The issue is I don’t know when the Criterion will be available.
 
I haven’t decided yet. Most people recommend the Criterion over the Wilson Combat. The issue is I don’t know when the Criterion will be available.

Well I'll tell you I recommend the Wilson Combat over the Criterion. I have one with lots of testing and it's been lights out. So accurate I've bought 4 more in different lengths and calibers which have shot equally as accurate. Wilson Combat are a hell of a deal for what you get. Don't hesitate