Pistol-caliber ARs have really taken off in the past few years, and it seems like almost everyone that makes an AR is jumping into the game. Until recently, most of those have been chambered in 9mm.

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Although this might seem like a new trend, some folks have been doing this for a long time. In fact, Quarter Circle 10 has been putting out dedicated pistol-caliber AR uppers and lowers in a variety of calibers since 2011. If you don’t want to build your own pistol-caliber AR, though, you’re in luck, because Quarter Circle 10 is making complete pistols and carbines, and I recently got my hands on the company’s QC10 GLF in .45 ACP.

Born In Texas

There’s nothing more Texan than cattle and firearms, and that’s the root of the Quarter Circle 10 name. No, it might not roll off the tongue, but this Texas-based company’s name can be traced back to a cattle ranch established back in 1854. That’s a lot of deep history, and it provides quite a legacy for the current company to live up to.

Quarter Circle 10 describes itself as a specialty weapons manufacturer of pistol- caliber carbine products. Its motto is “Made for, not modified,” which reflects the fact that it has been making parts dedicated to pistol-caliber ARs from the beginning rather than modifying rifle-platform AR receivers to take pistol-caliber magazines.

The company is headquartered in Texas, but its lower receivers are made in Tucson, Arizona, and other components are also American-made. The uppers and lowers are constructed from milled billets of 7075-T6 aluminum and treated with a black Type III hardcoat anodizing. The lowers are assembled using mil-spec lower parts kits and fitted with buffer assemblies designed and tested for pistol-caliber guns. For the QC10 GLF, the company adds an SB Tactical SOB brace as well as a basic A2-style pistol grip to the lower.

Quarter Circle 10 makes several styles of lowers to accommodate smaller-framed Glock magazines for 9mm, .40 S&W and .357 SIG guns; a large-frame Glock lower (like that tested) to accommodate the .45 ACP and 10mm; and lowers built around 9mm Colt and HK MP5 magazines. Models that will take Smith & Wesson M&P and Sig Sauer P229/P226 mags are also in the works. The lowers have clean lines with minimal stampings, with the manufacturing information and serial number on the right side and selector markings on both sides.

A Closer Look

The pistol operates via blowback, and the upper receiver’s walls are thicker than a standard rifle-caliber AR’s for increased rigidity and strength. You’ll also notice a widened ejection port for large-caliber pistol cases like the .45 ACP. My QC10 GLF pistol came with a 5.5-inch barrel capped with an A2-style flash suppressor, although a 7.5-inch barrel is also available. It’s surrounded by a 5-inch, free-floating KeyMod handguard that has QD sling mounting points on both sides. It also uses a dedicated .45 ACP bolt carrier group and a BCM Gunfighter extended charging handle. The pistol ships with a soft case that holds the pistol broken down into its upper and lower components, and one 13-round Glock magazine.

The QC10 GLF pistol retails for $1,646, which is a touch more than several other pistol-caliber ARs, but you’re getting a gun built from the ground up for the .45 ACP with no modified rifle parts, mag well adapters or anything similar. The gun is as trim and compact as can be while still having full AR capabilities, like the bolt locking back after the last round is fired, which you don’t always see on cheaper guns. About the only things I might like to see offered are a hand stop, especially with the short 5.5-inch barrel, and a single-point sling adapter. You can easily add both as aftermarket parts.

Range Setup

I hit the range with my buddy, Jim, on a cool, partly cloudy, 65-degree summer day. My range bag was stocked with .45 ACP ammunition of various weights and bullet styles, plus my Huntertown Arms Guardian 45 suppressor and LabRadar chronograph. I outfitted the QC10 GLF with a Holosun 510C reflex sight, which is a great choice for a pistol-caliber carbine or AR pistol. Its ring-and-dot reticle is fast to pick up yet precise enough for fine accuracy. It’s solar powered with a battery backup and is designed to be left on so it’s always ready when you need it. To feed the beast, so to speak, I had a mix of 13-round Glock magazines as well as 13- and 26-round SMG Tactical magazines.

Shooting the QC10 GLF is downright pleasant. The overall size of the pistol, coupled with the AR buffer, made for a platform that barely moved when fired. Add the BATFE’s clarification last year that it’s again OK to shoot your braced pistol from the shoulder provided you don’t modify the brace from its factory configuration, and you have an extremely controllable package.

After Action Report

The pistol’s reliability was very good overall, particularly with standard-weight .45 ammo. In fact, there were no stoppages with the 165- to 230-grain loads. We did have a few failures to eject using the PolyCase Inceptor ARX load initially, although those seemed to clear up during subsequent runs. These 118-grain bullets made it out of the 5.5-inch barrel at a little over 1,400 fps, and they cycle the gun’s blowback system much faster than it was probably designed for. The recoil and report were not unpleasant with both PolyCase loads, but they were more significant than with the heavier .45 ACP loads.

The QC10 GLF’s accuracy was excellent. Quarter Circle 10 is doing everything right with this build, as most loads were printing at about 1 inch at 25 yards, with even the basic Federal American Eagle 230-grain FMJs printing at less than an inch. The QC10 GLF didn’t care for the high-velocity polymer RNPs as much, but even those were still averaging less than 3 inches. Oddly, though, the even-lighter ARX load brought some phenomenal sub-1-inch, one-ragged-hole groups—the best groups of all of the loads from multiple shooting sessions. The Holosun 510C also proved to be a great match for the pistol, as it allowed for fast, accurate fire when putting rounds on target quickly or while moving but was still capable of providing precise hits from the bench or a stable standing position.

Covert Ops

Bear with me for a minute. The British De Lisle carbine was one of the more fascinating weapons of World War II. It was a modified Enfield bolt-action rifle chambered in .45 ACP that accepted 1911 magazines and incorporated a rather massive integral silencer. It was an extremely effective piece that was used in clandestine operations. I’ve always thought a suppressed .45 ACP carbine that accepted pistol magazines was a great idea, and although my test gun isn’t a carbine, the AR-based QC10 GLF makes for a modern take on that concept. I mated it with my Huntertown Arms Guardian 45 suppressor to cobble together my own 21st century De Lisle.

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Huntertown Arms isn’t doing a fixed-barrel adapter for the Guardian 45 as of this writing. In fact, we recently learned that due to the current softness in the suppressor market, Huntertown Arms is ceasing operations for now. That said, I had Josh Rowe of Allegheny Arms and Gun Works whip me up one for use in this article. Josh’s work is meticulous, and his adapter dropped in and had me shooting the QC10 GLF in no time. I used the heaver 230-grain bullets with the suppressor because they were subsonic.

The pistol’s performance and reliability were still 100-percent suppressed, although I saw a noticeable drop in my point of impact when I added the can. And though the Guardian 45 reduced the report of the pistol, we weren’t talking movie quiet. The big .45 made a fairly loud cough, but it was still substantially quieter than unsuppressed, and it was pleasant to shoot without hearing protection.

Final Thoughts

All told, if you’re looking for a quality pistol-caliber AR carbine or pistol, it’s difficult to go wrong with a Quarter Circle 10 product. Despite the current market explosion of pistol-caliber weapons, this company has been turning out quality products for years and has refined the art. The QC10 GLF offers top-quality components and features not found on some bargain pistol-caliber ARs. Although I tested the big-bore .45 ACP, Quarter Circle 10 can pretty much accommodate any common defense caliber and in a good variety of magazine configurations.

Quarter Circle 10 QC10 GLF Specs

Quarter Circle 10 QC10 GLF Performance 

*Bullet weight measured in grains, velocity in fps by chronograph and accuracy in inches for best five-shot groups at 25 yards.

For more information, visit quartercircle10.com.

This article was originally published in “Combat Handguns” July/August 2018. To order a copy and subscribe, visit outdoorgroupstore.com.