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


Not Sure

by -

I built a MK18 upper with this barrel and I am still undecided on whether or not I will keep it or replace it with a Ballistic Advantage 10.3 or a cut down Colt barrel. I've done two range trips with this barrel and have yet to get it to print a decent group. Using a red dot with a 3x magnifier I have been able to get around 4 to 4.5 inch groups at 50 meters. I use 50 meters as my usual red dot zero for carbines and have shot a mixture of M193 (55 gr), M855 (62 gr), and some Aguilla 62 gr FMJ. I have also had some cycling issues, both suppressed and unsuppressed, and have attempted to remedy this by changing buffer springs and various buffer weights which has me concerned about the actual gas port size being what the barrel is advertised to have. I don't want to label this barrel as a lame duck yet, so I will conduct some more T&E and follow up with my final assessment. RLTW!!

Nice to speak with you on this issue, please let us know if you would like to return that barrel. So we can get you taken care of.

Solid stuff


Accuracy is much better than expected. A very good option for a regular use SBR. Chrome lining is heavier than most, which came as a surprise. Had it for about a year and it's been great.

10 inch chrome lined barrel

by -

looks good, as advertised. Haven’t finished setting it up. Reasonable price.

Accurate 10.3 inch barrel.

by -

The barrel is sub moa and hits silhouette at 300 yards with M193. Needed to run a standard weight carbine buffer and spring to get it to cycle flawlessly, after 60 round break in. Very pleased.

Spares parts are necessary

by -

This was bought to have in the event that our trying to be communistic government actually gets there way . I have a few acquaintances that have these on suppressed platforms and they seem to do quite well. Can't beat a competent barrel at a good price.

Expo 10.3

by -

Bought this on sale for a pistol build. I’m definitely not disappointed. Shoots great and accurate.

Follow Up


I've had sometime to thoroughly test and break this barrel in and I can say that, after some trial and tribulation, that it does indeed work as intended. It now has around 300 rounds thru it and is working well. For my setup I had to take out the SpringCo blue spring and the H2 buffer and use a standard spring and a H1 buffer. Now the weapon fires both suppressed and unsuppressed without any issues. The groupings are a little tighter than before, but it is a 10.3 inch barrel so I should know better than to expect sub MOA at 100 meters. I trust this barrel and would buy another Expo Arms barrel again.

Excellent quality

by -

Great bang for your buck. Hard to beat chrome lined goodness

Great Barrel


This barrel is a sleeper for sure. I've been hammering away with it on a MK18 clone upper. I thought it would add too much weight but it isn't bad. I was mainly using it as a burner and then replace but dang it's super accurate and doesn't heat up as bad and has proper dimple and gas port. It's a exact clone of the socom profile. The 10.3 was always hard to find and it's priced good. Nice!

Excellent construction

by -

Heavy and excellent finish