SIONICS 12.5″ Barrel

from: $20995

The SIONICS 12.5” Chrome Lined Barrel is a high-quality, versatile barrel that is perfect for a pistol or SBR.

SKU: S-B-125-CL Categories: , Product ID: 14838


The SIONICS 12.5” Chrome Lined Barrel is a high-quality barrel that is made from 41V50 Chrome Moly Vanadium Steel. It has a medium contour, a carbine-length gas system, and a .750″ gas seat diameter. The barrel features hand-polished feed ramps and has a 1/7 twist rate. It is also threaded 1/2×28 and is manganese phosphate coated. The barrel is magnetic particle inspected and radiograph inspected. It is pre-dimpled for easy installation of the gas block. This barrel is a great choice for a general purpose pistol or SBR.


  • 12.5” Chambered in 5.56 NATO
  • 41V50 CMV Steel
  • Manganese Phosphate Coated
  • Chrome Lined
  • Medium Profile
  • .750″ gas seat diameter
  • 1/7 Twist Rate
  • Carbine Gas System
  • Magnetic Particle Inspected
  • Weight: 1 Lb. 6 oz.
  • Radiograph Inspected
  • Threaded 1/x28
  • Hand Polished Feed Ramps
  • Pre-Dimpled for easy Gas Block Installation
Barrel Specifications
Barrel Length 12.5 Inches
Chambering 5.56 NATO
Barrel Contour Medium
Twist Rate 1/7 Twist Rate
Thread Pitch 1/2 x 28
Gas System Carbine Length
Gas Seat Diameter .750
Barrel Material 41V50 Chrome-Moly Vanadium Steel
Outer Coating Manganese Phosphate Coated
Inner Coating Chrome Lined
Weight 25.6 oz / 726 g

Key Features of the SIONICS Upper Receivers and Barrels


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The SIONICS barrels utilize 5R Rifling. 5R Rifling helps fight bullet failure due to a softer angle on the sides of the lands vs. conventional style rifling that utilizes 90° corners of the lands, which is a very hard edge.  Furthermore, with 5R, you have 5 lands in the bore of the barrel.  The odd number of lands does not directly oppose one another. The combination of these two things deforms the bullet less – less distortion to the bullet jacket when the bullet makes the jump from the case into the rifling.  This helps fight bullet failure and increases the inherent accuracy of the barrel.  Lastly, the gentler edges of lands on the 5R Rifling allow easier cleaning of the bore.  The 90° corners of conventional rifling make it harder to reach lead and other contaminants when cleaning.  The softer edges of the lands on 5R Rifling allow for a much more thorough cleaning process.

Our 11.5″ and 12.5″ barrels come only in a 1/7 twist rate and our 16″ barrel comes in a 1/8 twist rate.

Our barrels are Manganese Phosphate coated. Manganese Phosphate is coating on the outside of the barrel using a sprayed or immersed salt bath to achieve a somewhat porous finish that then more readily accepts and holds lubrication to help prevent corrosion.

Chrome lining is a treatment applied to the inside of SIONICS barrels. Chrome lining is essentially an alternative to a Melonite/nitride finish. During this process, chrome is applied to the lands and grooves of the barrel’s rifling, as well as the chamber. In order to ensure accuracy with this extra material, chrome-lined barrels are typically bored out more than the final internal diameter. The tolerances are made up by adding the chrome to the inside of the bore.

The quick answer; as long as it’s 5.56 or .223 then it will work great. That being said, we test fire all of our firearms, uppers and BCG’s using Magtech M193 55gr 5.56 ammunition.

Currently all of our barrels are chambered in 5.56 NATO.

Our test rifle, “Chuck Norris”, has had over 200,000 rounds through it with very little cleaning or maintenance and still runs great, so you be the judge.

By sending all of our barrels to Radiograph, or X-Ray testing we are able to identify possible structural defects within the barrel.

This is an example of a barrel defect that would not be detected to the naked eye.