Aero Precision 308 OEM Review

[ace4059]

Let me start by saying this review was written over the course of a few weeks so where something can be seen as good with my first initial impression, it can be later be viewed as troublesome in the range report. E.G. Tight bolt.

Aero Precision 308 OEM Review.
First here are the specs that brownells lists so you do not have to look them up. The specs seem to be good especially for a gun that's under $1000.
Link to Brownells
http://www.brownells.com/rifle-parts...AERO+PRECISION
• 308 AR Aero Precision Upper and Lower Receiver
• Rifle Length Gas & Barrel System with Low profile gas block
• 18” 308 Winchester, 1:10 Twist Barrel
• Barrel is machined from 4150 Chrome Moly Vanadium steel, with a tapered profile, then treated with a QPQ corrosion-resistant finish.
• 5/8-24 barrel thread pitch includes an installed A2 flash hider
• 308 Bolt/Carrier Group features 8620 steel carrier with phosphate finish & chrome lining, and has a properly-staked Gas Key
• Bolt machined from 9310 steel – High Pressure Tested & Magnetic Particle Inspected 308 AR Aero Precision Lower Receiver
• Accepts DPMS 308 components & magazines (PMAG compatible)
• Flared mag well & upper tension screw
• Standard 308 AR Lower Parts Kit
• Mil-spec AR-15/M14 Buffer Kit
• Forged from 7075 T6 Aluminum
• Matte black hard anodized finish
• DPMS short buffer

Initial Impressions
The parts are nicely machined and the finish is top notch. This appears to be a quality finished firearm that has attention to detail. I am liking it out of the box. The upper and lower fit nicely and the color matches well. The barrel has a nice taper that lighten it just a little but has a nice heavy contour which looks to produce minimal POI shift with the suppressor. The bolt fits tight inside the carrier and the bold catch/release is a snug fit. The threading looks concentric to the bore. but I have no way to measure it, I can only go by looks. The charging handle has a tight pull at first then it loosens up once the lugs unlock, the BCG slides freely inside the upper.
The OEM design is basically a user build platform which it comes bone stock without all the add ons which most people end up replacing items on their AR, so the OEM offers a base to build off of without wasting money by adding the parts the end user doesn't need. I am a fan of this concept because it keeps from adding to the spare parts bin and my garage from accumulating junk. Basically the user has to add a stock, forearm/rail, and sights at minimum. So far I am impressed and this looks to be a quality gun.

[ace4059]

The Build.
When I started disassembling the gun to add the parts, I noticed most of the parts seemed to be hand tighten only. This led me to disassemble most of the gun and tighten everything to proper torque specs. The barrel nut was barely tight which I replaced with a Fortis Anti-rotation barrel nut for the Fortis Switch Rail (DPMS high rail). Others have suggested that Aero Precision does not tighten nor crank down the nuts and bolt because they know the user will be having to disassemble the rifle to add their own parts.
The low profile gas block was properly aligned with the barrel gas port but the barrel was not notched for the set screws. I used the jig and notched the barrel on the minimal side to retain the setscrews for the gas block. Blue locktite was applied and it was reassembled. While I had the gas block off, I measure the gas port with a drill bit. I had a .080" drill bit and a .090" drill bit. The .080" drill bit was very loose and the .090" barely would not fit so I am taking a guess that the gas port is around .087"

The barrel is not dimpled for the gas block.


Center punched the hole.


One good this is the gas block was properly lined from the factory with the gas port. The jig verified this and the barrel was dimpled


The A2 flash hider was removed and an SilcecerCo flash hider was installed with Rocksett for my 762 Specwar suppressor. The suppressor aligned well with the bore and I did not have any baffle strikes while firing the gun.

The magazine release looks to be a standard AR-15 button and the magazine catch also looks to be a standard AR-15 design. The AR-10 is wider so the screw only catches with about two turns and there is a large gap inside the button where the screw should be flush with the button. To fix this issue I used a Battle Arms Development Enhanced magazine catch button. It fit nicely and is a quality design.
With me being left handle the BAD-ASS is an automatic install on all my AR's.

Notice the screw is barely threaded into the magazine release button


Even with the mag release button screwed flush with the side of the lower there is still a gap from the screw not being flush with the mag release


BAD enhanced magazine release installed. This does a nice job of hiding the gap where the mag catch screw doesn't thread all the way in the back of the mag release button.


The AP factory trigger is on the lighter side for a MIL-SPEC trigger and has a smooth clean break. This is comparable to a ALG trigger. Very nice for a factory trigger. I was having accuracy issues with this firearm so I replaced the trigger temporary with a Giessele SD-E trigger to be absolute sure I was getting a clean break. This did not help with the grouping.





The castle nut was staked in one notch but the staking was what I could call the bare minimum. I replaced the receiver plate with a IWC QD plate and staked the castle nut in two notches.

Factory staking


The BCG had a nice finish and the gas rings had a nice fit. The bolt is on the tight side and will not slide easily into the carrier. It is so tight you just about have to use a rubber mallet to put the bolt back in the carrier. The extractor spring had a dual spring and two (2) O-rings.

Nice finish but notice the small gap where the mag catch fits inside the lower


Dual spring and two o rings



The charging handle is just the plain style charging handle.
The Aero Precision uses Allen screws instead of the standard roll pins for the Forward assist and Bolt Catch. I was on the edge about this design initially but I now like the idea of it because of the ease of replacing parts. More on this later.

Thankfully the Allen screw made replacing the bolt catch and forward assist easy



The Foregrip that the AP 308 comes with is the standard A-2 style grip. I replaced it with a Magpul grip and when replacing the grip, you can easier adjust the tension screw that eliminates the play or slop between the upper and lower. This screw was about to fall out when I removed the foregrip. It was installed with maybe a half turn. I tightened it on the minimal side for a firm but not overly tight to apply pressure on the upper. The threading for the grip screw was smooth and threaded all the way. I have ran into problems with different brand lowers where they were not properly threaded. This AP was easy and hassle free on installing the grip.

[ace4059]

Range Testing.
This is where my love for the Aero Precision 308 OEM stops.
I did a few standard function tests with the rifle. The first thing I noticed was the Forward Assist would not push the BCG forward. Through a little internet research some people said the F/A could be out of spec and is on the short side. The F/A is a standard AR-15 part. I called Aero Precision and in short order I had a new one in the mail.
I loaded up several magazines with one round each to make sure the bolt would lock back. My first impression was the gun was over gassed. I was getting an ejection pattern of about 2 o'clock. On round number six (6) the bolt failed to lock back. The culprit, broken bolt catch. So another call to AP and I had a new part on the way. These parts took a few days to arrive in the mail from Washington to Texas.

Remember when I said I was on the fence about the Allen screws hold key components instead of roll pins, well these Allen screws made changing the parts a breeze. That was a wasted range trip. The six shots were all over the target.

Bolt catch snapped on round number 6


Bolt catch and F/A replacement. AP was quick to send these replacement parts out.



Now I have the parts replaced and its back to the range. With the prior shots all over the paper, I gave the gun another through cleaning and paid special attention to the bore. I took a coated Dewey cleaning rod with me to the range to do a barrel break in because I was hoping the groups would tighten up. After a 20 round break in the groups were still having a vertical string and no consistent grouping. I attached my 762 Specwar suppressor and the grouping shifted about 12" to the left. I redialed the scope and was hitting about center mass again. The groups were so bad I was now checking the scope to see if the QD mount was loose. This vortex scope was been used on my other gun for testing and I placed it on my AR-15 that I had in the truck. I dialed it in after a few rounds and was getting solid 1 MOA groups with the scopeon the AR-15. No wondering zero and the screws were all tight. I had a few Failure to ejects with the AP 308 but I just thought the gun needs a few rounds to break in. With the suppressor the ejection pattern was at 12 o'clock. I did not know a gun could throw brass in front of the barrel like that. These factory rounds were showing pressure signs. They had ejector swipes and the primers had a deep strike with a ring around the indention. There were a few of the 762x51 lighter loads that were ejecting at 4 o'clock without the suppressor. This ejection pattern has marred up the front side of the receiver where the front of the dust cover would be. This leads me to believe that it could have a tight chamber.


Grouping


So my next thoughts were the Aero Precision did not like this type of ammo. I went to the store the next day and bought a few different brands and bullet weights and hit the range again. The first thing I noticed was when switching between brands the groups would shift several inches. This not unexpected because on my other guns the groups will shift between point of aim and point of impact a few inches (2"-5") but with this 308 the shifts were in 12"-20". With all the different ammunition the groups were 6"-8" on average. My best groups were with Federal Premium Match 175 gr Sierra MatchKing. My bolt guns shoot this stuff 1/2-3/4MOA but the AP was shooting about 4 MOA with this stuff. I knew then something was wrong so I went home to re-inspect the gun.

I tried several boxes of different ammo


Groups








Best groups





You get the idea on the poor accuracy of the barrel.



I got home and took the barrel nut off and re torque it on the lighter side of 35lbs I didnt find anything wrong. I removed the two O-rings from the bolt to see if that would help with the failure to ejects. I tried it a few different way and still had several failure to ejects. The next several range trips were frustrating. The bolt catch/release had always been on the tight side but it has become so tight where you can not release the BCG to charge the firearm with your thumb. It is binding and takes two hands pressing as hard as I can to release the bolt. The only practical way to charge the firearm is with the charging handle. The bolt is still very tight inside the chamber. It acts as if Bolt lugs are sticking in the barrel extension and you have to pull forcefully to first open the bolt. Once the lugs clear the barrel extension, the BCG slides effortlessly. But there is no visible wear on the bolt lugs, which leads me to believe the it is the bolt sticking inside the carrier because it is so tight.

Failure to eject






Notice it's damaging the brass by bending the case mouth. Looks like the 300 blk out case mouth.


Something is leaving lines on the brass




Video of the bolt catch not releasing the bolt.
http://youtu.be/K8gwii7zZis




I later discovered I had broken a second bolt catch and I am now on my third. That was the cause of the bolt catch not releasing the bolt.



Notice how the bolt catch is bent


Crack in bolt catch





I noticed the charging handle has high wear on the top of it and around the latch area for the few times I have used it (less than 50). Something is really cutting into the aluminum and it as almost as if the charging handle is too big to fit into the upper receiver. I'll probably replace it with a BCM. Sorry I did not take any pictures since I noticed it as I was boxing up the gun and getting it ready to send back.


I fired 180 total of the course of multiple range trips with poor grouping and frustrating experiences. I purchased this rifle with the intention of doing a review since the Aero Precision 308 OEM version is fairly new for the company and their upper and lowers get good reviews. I tried to contact Aero Precision for several weeks and never could get through. I left numerous messages and sent several emails and it took Aero Precision almost three weeks for them to contact me back. They sent me a return label and I mailed it back Yesterday. I will update this article when I receive the firearm back. Contacting AP was a hassle and I was on the verge of sending the gun back to Brownells for an exchange. Since AP did finally contact me I am going to let them fix the firearm.

This is not a review to hate on AP. I want to like the gun because of the money and time I invested into it, but with the four MAJOR problems of terrible grouping, failure to eject, bolt release sticking, and bolt sticking in chamber, as of right now I cannot recommend this firearm. It is intended for educational purposes and to show the quality that AP has so buyers can make informed decisions in the future. I was hoping this would be a great gun and AP would break the mold by releasing a reliable 308 AR for under $1,000 but it looks like they have more work to do. Don't get me wrong, this could be a nice gun with some changes and I would like to say I received a lemon and this just slipped through QC but I will hold my judgment until I get the gun back.

[ace4059]

Final thoughts

This firearm is a good base for the upper and lower. My thoughts are the barrel needs to be replaced along with the BCG since I feel both are out of spec. The barrel needs an adjustable gas block if you are using a suppressor. The LPK seems to have poor quality since AP did not catch the FA being out of spec and the AP bolt catches keep breaking. You may want to replace the key components in the LPk.

More updates will follow.

[ace4059]

Saved for updates at later time

[ace4059]

saved for future updates

[RHINOWSO]

Thanks for the detailed review. I've been tempted by APs OEM 556 and 308 offerings, but I'll be holding out for awhile.

[JoshNC]

I hope they get the BHO failures worked out. Also would have been nice if they made the upper and lower SR25 compatible.

[ace4059]

It is currently at AP. Hopefully I'll hear something next week.

I originally purchased this AP 308 to put a free float rail on it and use it for hog hunting with my pvs-22 and dbal.
One of the reasons I purchased it was for a review and comparison for cheaper AR10's, and it has more options for rails compared to my M&P 10 (high rail vs low rail). My M&P 10 doesn't have a free float rail on it.

[ace4059]

I sent a reply to AP last week and they sent me a message today. Basically what I got from the message was they shot 20 rounds through it and it worked so the replaced the bolt catch (the one that was cracked and bent) and are shipping it back to me.

I sent a message back to them asking about the accuracy issues. I expected at least a barrel replacement since that one shoots like crap.

Here is their message:
Sir, So I just got your rifle back from the armorers, and from what they told me, they replaced the bolt catch and it does send the bolt home when pushing it. They fired a total of 20 rounds through the weapon and did not experience any misfires or malfunctions. It is still bit a stiff when pulling back the charging handle, but this is a common issue for .308s where the spring is a bit tense and will loosen up over time. Regarding the pressure, they did not experience any issues when firing regular pressure rounds, but did note high pressure damage when firing high pressure rounds. I will be bringing your rifle downstairs to be shipped out today, so it should be leaving our facility within the next day or 2.

Here is my reply:
So your armory did not even address the accuracy issues? It is just going to break more bolt catches since the barrel is over gassed. The problems with the barrel need to be addressed. You may want to read this before you send it back https://www.m4carbine.net/showthread...308-OEM-Review



I will see if they reply back and will keep this post up to date. I can fix the overgassed issues with an adjustable gas block if I have to, but I cant fix the accuracy issue without buying and changing out the barrel. I guess 4-6 MOA is acceptable to them...

-Ryan