One Horse Parts · Complete Uppers
American made · Brownstown, Indiana
Shop a 300 Blackout upper built as a complete .300 BLK upper: 4150 barrel with a 1:7 twist, free-float M-LOK handguard, M16 Black Nitride BCG and charging handle installed. American-made by One Horse in Brownstown, Indiana. Fits a mil-spec AR-15 lower and ships straight to you—no FFL needed for an upper.
The basics
A One Horse complete upper is ready to pin onto a mil-spec AR-15 lower: barrel, free-float M-LOK handguard, M16 Black Nitride bolt carrier group and a standard charging handle, all installed.
.300 BLK and 5.56/.223 use the same BCG. What changes is the barrel: One Horse .300 BLK barrels use a 1:7 twist and a 5/8×24 muzzle thread—the same twist on every length we cut in Brownstown. Pair a complete upper with our M16 nitride BCG, a complete lower, or a 300 Blackout suppressor hub. For a starting buffer, see H2 buffer weight in our buffer chart.
Each One Horse .300 BLK upper runs both supersonic and subsonic loads.
Side by side
Specs from the One Horse product pages. Prices are live from the store.
| Spec | 7.5″ | 10.5″ | 16″ |
|---|---|---|---|
| Barrel | 7.5 in., 4150, Medium profile | 10.5 in., 4150, Medium profile | 16 in., 4150, SOCOM profile |
| Twist / thread | 1:7 · 5/8×24 | 1:7 · 5/8×24 | 1:7 · 5/8×24 |
| Handguard | 7 in. M-LOK, free-float | 10 in. M-LOK, free-float | 15 in. M-LOK, free-float |
| BCG | M16 Black Nitride (included) | M16 Black Nitride (included) | M16 Black Nitride (included) |
| Charging handle | Standard (included) | Standard (included) | Standard (included) |
| Fits | Mil-spec AR-15 lowers | Mil-spec AR-15 lowers | Mil-spec AR-15 lowers |
| Price | $319.99 MSRP | $349.99 MSRP | $369.99 MSRP |
Our take
Still choosing a caliber? Read 300 Blackout vs 5.56.
Suppressor
The Ryn .30 cal is tested on 300 Blackout and ships with a 5/8×24 Plan B mount, the same thread as One Horse .300 BLK barrels. Plan B mount included. On the One Horse performance chart it took 20.6 dB off at the muzzle on an 8″ 300 BLK pistol. Results vary with barrel, ammo, mount and conditions. Always wear hearing protection.
Shop
SKU: OH-CU06
SKU: OH-CU05
SKU: OH-CU04
Complete uppers ship to you. The Ryn ships to your dealer, who must hold an SOT. Free shipping on orders of $399 or more.
Finishing the build
Want a different finish? See every option in the AR-15 BCG guide. Need a lower? See One Horse AR-15 lowers. Want the short uppers side by side in both calibers? See short AR-15 uppers and the 10.5″ upper guide.
Questions
Three complete uppers: the 7.5″ .300 BLK upper, the 10.5″ .300 BLK upper and the 16″ .300 BLK upper. Each one comes with an M16 Black Nitride BCG and a standard charging handle installed.
Yes. One Horse .300 BLK complete uppers are built for any standard mil-spec AR-15 lower receiver.
Yes. .300 BLK and 5.56/.223 use the same BCG. Every One Horse .300 BLK upper ships with the M16 Black Nitride BCG installed.
All three use a 4150 steel barrel with a 1:7 twist and a 5/8×24 muzzle thread. The 7.5″ and 10.5″ barrels are Medium profile, and the 16″ barrel is SOCOM profile.
Yes. Each One Horse .300 BLK upper is chambered for .300 BLK and runs both supersonic and subsonic loads.
The Ryn .30 cal. It is tested on 300 Blackout and ships with a 5/8×24 Plan B mount, the same thread as One Horse .300 BLK barrels. Plan B mount included.
No. A complete upper is not the serialized part, so it ships straight to you. Check your state and local law before you order.
Orders of $399 or more ship free.
Yes. One Horse makes these uppers and backs them with a Limited Lifetime warranty.
American Made · Family Owned · Veteran Owned
7.5″, 10.5″ and 16″ complete uppers with the BCG and charging handle installed, made in America.
Federal, state and local laws vary and change, and it is the buyer’s responsibility to follow them. Questions? Call 812-200-0305 or email customerservice@theonehorse.com.
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Free shipping on orders $399 or more
