The Low Mass Sharps Xtreme Performance Bolt (XPB) Carrier Group Complete is comprised of our patented Relia-Bolt™ and our Special Low Mass Balanced Bolt Carrier. Low Mass Carrier is 1.7 ounces lighter than the Full Mass Carrier. Made specifically for competition shooters.
The XPB undergoes a 24-hour thermal cycle proprietary heat treatment, and is finished with the DLC (Diamond Like Carbon) Coating. The XPB carrier displays the SRC logo machine cut and is visible when the ejection port door is open. The XPB fits standard AR-15/M16/M4 rifles chambered in .223/5.56, Sharps 25-45, and 300 Blackout calibers.
|Bolt and carrier:||S7 tool steel, shot peened and DLC coated (U.S. Patent No. 9,863,729)|
|Gas Key:||4130 Steel. attached with Grade 8 hardware, properly staked and DLC coated.|
|Cam pin:||4340 Steel, Manganese Phosphate coated|
|Firing pin:||Mil spec made of 8740 Steel, center-less ground, and Hard Chrome coated.|
|Extractor:||4340 Steel, Manganese Phosphate coated|
|Ejector:||S7, shot peened and Manganese Phosphate coated|
|Extractor pin:||S7, shot peened and Manganese Phosphate coated|
Mil-Spec Extractor and Ejector springs, Firing pin retaining pin, Gas Rings
Why S7 Tool Steel?
S7 has excellent shock absorbing properties which provide superior impact resistance when being utilized in the construction of Sharps Bolt Carrier Groups. S7 demonstrates high strength and toughness as well as a resistance to softening at moderately high temperatures, i.e. operating temperatures not exceeding 1000°F.
The properties we as shooters look for in an AR platform BCG, are hardness and wear resistance. S7 provides such attributes when heat-treated properly. Sharps has found that the key benefits from S7 tool steel are higher tensile strength and toughness which translate to longevity of use, i.e., a higher number of cycles the bolt can handle before it fails.
Technical Data on DLC Coating
|Coating thickness:||2-4 Microns|
|Hardness HV 0.05:||HRC 80+|
|Deposition method:||PVD UBM/PACVD|
|Friction vs Steel:|
- Weight: 9.5 oz
- Batch MPI and HPT tested
- Tensile Strengths of 1550-1600 mpa, or 220,000-235,000 psi.
- Toughness over 200ft/lb Charpy C-Notch
- HRC of 46 yields a 15% increase in hardness at the same toughness comparing to Carpenter 158 & 9310.
Limited Lifetime Warranty
If any SRC Bolt Carrier or Relia-Bolt™ is found to have manufacturer defects, SRC will repair or replace it at no charge. Manufacturer defects include out of spec parts and defective parts. Although our BCG is Mil-Spec, there are so many variables, sometimes a little troubleshooting, or fine tuning of parts may be required for proper functionality. Before a part is replaced or refunded, SRC reserves the right to inspect and test part(s) in question to determine if it is defective. Please keep in mind that altering the product renders the warranty void.
Note: Binary triggers will NOT work with the low mass carrier.