1. Home
  2. AR-15
  3. Barrels
  4. XP-B-556-103-SOC-C

Expo Arms 5.56 NATO Chrome Lined AR-15 Barrel - SOCOM Profile - Carbine Length - 10.3"

Manufactured by Expo Arms
SKU: XP-B-556-103-SOC-C
MPN: XP-B-556-103-SOC-C
Manufactured by Expo Arms
37 Reviews

Out of Stock

For individual Officer, First Responder, and Military pricing please make sure you are logged in. for details



The Expo Arms AR-15 Barrels are designed to give you a premium barrel at an affordable cost. This AR barrel is made from Mil-Spec 11595E certified 4150 steel and features a chrome lined bore to withstand high temperatures for a long barrel life. This 10.3” model features a SOCOM profile with a carbine gas system and .070” port diameter for reliable function. Additionally, the .750 gas seat diameter is dimpled for securely attaching set screw gas blocks. The 1:7 twist rate is optimal for heavier 62 grain ammunition and the muzzle is threaded 1/2x28 for your favorite 5.56 muzzle device. The entire 5.56 Barrel is Phosphate coated for corrosion resistance and oil absorption. If you are looking for a combat ready barrel that provides exceptional accuracy and reliability, you can’t go wrong with an Expo Arms M4 barrel.

Note: Due to the Crane-Spec gas port size of .070” this barrel was designed to function both unsuppressed and suppressed with 5.56 NATO pressure ammunition. Unsuppressed use with lower pressure .223 Remington ammunition may not yield the best results regarding function.

  • 10.3” Government profile chambered in 5.56 NATO
  • Carbine gas system with .070” port diameter
  • .750” dimpled gas block shelf
  • Made from Mil-Spec 11595E 4150 steel
  • Chrome lined bore with Phosphate outer finish
  • 1:7 twist rate and 1/2x28 muzzle thread
  • M4 feed ramps
Expo Arms offers top-quality MIL-SPEC AR-15 components at rock bottom prices. Made in the U.S.A. and covered by Expo’s Limited Lifetime Warranty against manufacturer defects, material or workmanship problems, and even normal wear and tear.
See More


Barrel CoatingManganese Phosphate
Barrel ContourSOCOM
Barrel Length10.3
Barrel LiningChrome
Barrel Material4150 Chrome Moly Steel
BrandExpo Arms
Caliber Gauge5.56 NATO
Feed RampsM4
Gas Seat Diameter.750
Gas System LengthCarbine
Thread Pattern1/2 X 28
Twist Rate1:7
California Prop 65 warning

 WARNING: This product can expose you to chemicals, which are known to the State of California to cause Cancer and Reproductive Harm. For more information go to www.P65Warnings.ca.gov.

Ratings & Reviews

37 reviews


Fantastic quality barrel


Chrome lined, SOCOM profile, Crane Spec .070 gas port - what else could you ask for? Runs beautifully suppressed and unsuppressed with an H3 buffer. Fully recommend this barrel for anyone wanting to build a high quality, inexpensive 10.3" upper.

Very good bang for the buck.


I bought one on sale, if I would’ve known how much I liked it I would’ve bought a couple more. I put it together with an Expo gas block, had some gas issues with function way under gassed, with standard buffer, and wouldn’t lock bolt to the rear on last round fired. I wasn’t surprised about that and from what the add stated don’t be surprised, with 223 or weaker ammo. The gas port was .070 as advertised, I opened it up carefully to .077 and with new carbine spring and H buffer runs about 3:30. Very good quality and very pleased.

Great barrel

by -

Great shorty barrel for anyone on a budget. Stout and chrome lined. Shoots like a dream.

Great Barrel

by -

Best kept secret as far as "heavy profile" barrels go IMO

Had some issues with cycling unsuppressed

by -

I tried everything with this barrel and was thinking I had done something wrong on the build. Rechecked all gas components numerous times. Tried from carbine to h4 buffers and still the same result. Double feeds and short strokes. The lighter buffer would run ok ish but still would not lock back with any of them. I would up stepping up the gas port on the barrel one size and as if by magic this thing finally started running like it should have all along. I have an H2 buffer in it but may venture to a heavier one to get softer recoil.

Buy this barrel now! It's definitely a sleeper.👍👍


Excellent! Barrel is beautifully finished and clear of any defects upon arrival. Installed on an MK18 build and WOW!! This thing is very accurate. Was able to get sub to 1 MOA 10 shot groups at 50 yards with Federal M193. As far as gassing goes, ejection is consistent at 3:30 with standard spring and H1 (gas tube and block, buffer weight, BCG are all Epo Arms products). I have not tried it suppressed yet but I'm sure it would yield great results with tuning. Don't sleep on this barrel, definitely worth the low cost even if it's a placeholder for a Gucci barrel or spare. You might even scrap that idea like I did. Lol.

Hard to beat for the price

by -

The Crane-Spec gas port means you'll probably need a carbine buffer to have it cycle reliably unsuppressed and make sure your gas block is aligned properly. With this port size there is no margin for error. When these go on sale, you'll kick yourself if you don't get more than one.