Aero Precision 6mm ARC Upper Receiver (and M4E1 Lower)

As I mentioned previously, I had no intention of getting into a new cartridge this year. Yet, that’s exactly what I did. Admittedly, it was a decision that I could attribute to curiosity emboldened by a good deal. In other words, it was an impulse buy. Technically, it was two impulse buys, but who’s counting anyway?

It happened, predictably, whilst I was perusing social media and catching a few threads buzzing with 6mm ARC goodness. Curiosity did, in fact, get the best of me and I ended up surfing Brownells when I came across a complete upper receiver chambered for the 6mm ARC cartridge on sale. The upper had several variants offering different barrel lengths and finishes. However when I came across it, the only variant left in stock was the one with a 24″ barrel in a stainless steel finish. So, I did the only thing a reasonable enthusiast would have done and ordered it.

The upper receiver arrived in a padded cardboard box along with a free Aero sticker. The upper with the 24″ barrel was massive. My original intent was to attach it to the Daniel Defense DDM4 V11 lower receiver. However, I came across a good deal on a complete Aero M4E1 lower receiver which included a Magpul MOE grip and a PRS Gen3 rifle stock while helping a friend find a good deal on an Aero upper receiver. So once again, I did the only thing a reasonable enthusiast would have done and ordered it.

At this point, one could say this is a complete Aero Precision AR-15 chambered for 6mm ARC with a 24″ heavy profile barrel.

Starting from the tip and working our way to the butt, we have the VG6 Gamma muzzle device attached to the 5/8×24 threaded muzzle on the barrel. The VG6 Gamma is a muzzle brake and compensator hybrid. According to what I’ve read and heard about it previously, it mitigates recoil very well. Unfortunately, I can’t confirm how well the muzzle device performed well or not because this is my first experience using this device and cartridge so I have no point of reference to compare it it. The only thing that I will add is that I like the way the bead blasted stainless steel finish looks, but it gets very dirty quickly.

Behind the muzzle device we have about 8.5″ of the 24″ heavy profile barrel exposed before reaching the end of the hand guard. I’ll get to the hand guard shortly, but first let’s talk about the barrel with a 1:7″ twist rate. The barrel is a Ballistic Advantage premium series barrel machined from 416 stainless steel with a bead blasted finish which includes a nickel boron coated extended M4 feed ramp. The barrel features a rifle length gas system that is connected via a fixed gas block with a .936″ journal.

The hand guard is a 15″ long Aero Precision M4E1 series lightweight free-float handguard. M-LOK attachment points are available along the entire length in the 3, 6, and 9 o’clock positions along with a full length picatinny rail at the 12 o’clock position. The 1.72″ inside diameter will fit most 1.5″ diameter muzzle devices and suppressors, which is irrelevant when it’s floating around a 24″ barrel.

The handguard meets up with an AR-15 enhanced upper receiver. I honestly have no idea how it is enhanced. That’s just what the marketing material calls it. The upper is completed with a standard AR-15 charging handle and houses an Aero Precision black nitride finished 6.5 Grendel/6mm ARC bolt carrier group.

That pretty much completes the tour of the upper that I slapped on an Aero Precision M4E1 complete lower outfitted with a MOE group and PRS Gen3 rifle stock. I didn’t find much about the lower receiver, controls, grip, or trigger noteable. All of those parts are fairly standard with the exception of the integrated trigger guard that is forged and machined directly into the lower receiver and the flared magwell. I’m impressed with the stock as it allows me to get a very consistent and well tuned length of pull and comb height. Given the long range capabilities of the 6mm ARC cartridge and the very long 24″ barrel, the stock seems to pair well with this setup.

So how does it shoot? Well, I’ll start by saying that this setup is a tack driver as long as I do my part. At this point, I haven’t stretched its legs beyond 100 yards. However, it punches clean holes on paper with precise authority. Recoil from the 6mm ARC was virtually nonexistent. I suspect this is due to a number of reasons including, but not limited to, the heavy rifle, the muzzle device, and nature of the 6mm ARC cartridge.

There are a few things I want to improve on the rifle. The first thing is a trigger upgrade. The trigger on the M4E1 lower is okay. It feels very much like a trigger from a standard lower receiver parts kit. It works. However, I’d like to replace it with a Geissele SSA-E trigger to improve both the shooting experience and the precision potential of this rifle for long distance shooting and perhaps hunting applications. Next up will be replacing the VG6 Gamma muzzle device with a muzzle brake that is compatible with a suppressor. While I’m not looking forward to adding even more length to this rifle, I want the option to run it suppressed.

As I’ve said before, I’m quickly becoming a fan of the 6mm ARC cartridge and this rifle has been a contributing factor. I’m looking forward to spending some more time behind it on the range and in the field in the near future. Who knows, I might even take it along on a hunting trip before the current deer season ends.