5.56 Sharps Xtreme Performance Bolt (XPB) Carrier Group Complete in NiB-X (Nickel Boron) Silver Carrier and Bolt


5.56 Sharps Xtreme Performance Bolt (XPB) Carrier Group Complete in NiB-X (Nickel Boron) Silver Carrier and Bolt

$249.99 $214.99

(13 customer reviews)

The Sharps Xtreme Performance Bolt (XPB) Carrier Group Complete is comprised of our patented Relia-bolt, and our Balanced Bolt Carrier. Both Balanced Carrier and the Relia-Bolt are coated in NIB-X (Nickel Boron).


Out of stock



The Sharps Xtreme Performance Bolt (XPB) Carrier Group Complete is comprised of our patented   Relia-Bolt™ and our Balanced Bolt Carrier. Both are machined out of S7 tool steel. The XPB undergoes a 24-hour thermal cycle proprietary heat treatment and is finished with NiB-X (Nickel Boron) 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.

Note:  Sharps will not guarantee proper function with Palmetto State Armory/Noveske platforms.  

Sharps will not guarantee proper function with the use of  steel cases, or foreign ammunition.

Color: Silver

Order cancellations may incur a 15% restocking fee.  Please see return section

Limited Lifetime Warranty

If any SRC Balanced Bolt Carrier or Relia-Bolt™ is found to have manufacturer defects, SRC will repair or replace it at no charge.  Manufacturer defects include broken lugs, out of spec parts or 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.


Technical Data
Bolt: S7 Tool steel, shot peened NiB-X coated (U.S. Patent No. 9,863,729)
Bolt Carrier:
S7 Tool steel, shot peened and NiB-X coated
Gas Key: 4130 Steel, attached with Grade 8 hardware, properly staked and NiB-X Coated
Cam Pin: 4340 Steel, Manganese Phosphate coated
Firing Pin: Mil Spec firing pin made of 8740 steel, center‐less ground and Hard Chrome coated
Extractor: 4340 Steel, NiB-X coated
Ejector: S7, shot peened and Manganese Phosphate coated
Extractor Pin: S7, shot peened and Manganese Phosphate coated
Mil-Spec Ejector Springs, Firing Pin Retaining Pin, Gas Rings

Batch MPI and HPT tested
Tensile strengths of 1550-1600 mpa, or 220,000-235,000 psi.
Toughness of over 200 ft./lb. Charpy C-Notch
HRC of 46 yields a 15% increase in hardness at the same toughness comparing to Carpenter 158 & 9310

NiB-X Coating:
Specifically engineered NiB-X nickel boron coating to provide long life, high reliability and easy cleaning and maintenance. The BCG components are coated and polished to reduce fouling adherence.  Especially beneficial in short barrel setups and suppressed platforms.
Hardness HV 0.05: HRC 70+
Friction vs Dry Steel 0.1
Color: Hyper Silver (Polished)

Additional information

Weight 11.20 oz

13 reviews for 5.56 Sharps Xtreme Performance Bolt (XPB) Carrier Group Complete in NiB-X (Nickel Boron) Silver Carrier and Bolt

  1. Brian Matlock (verified owner)

    Converted all my AR’s to the XPB, the NiB-X just makes it a dream to clean. IMO it’s a go to war BCG. Very impressed.

  2. Michael Dague (verified owner)

    This is my second Sharps bolt and bolt carriage, when shooting 3 gun fraction of seconds count the Sharps bolt and bolt carriage cycle faster and softer then the average system allowing to get back on target quicker saving you time.
    The bonus is cleaning is a breeze, no scraping or soaking in solvent just wipe off, lubes and go.

  3. Kelly Kendall (verified owner)


  4. Eric Frisch (verified owner)

    I have several other BCG’s to compare the Sharps to and it is by far the best hands down. It cycles smoother, has less felt recoil, and just looks good. I will never buy another brand BCG. If your on the fence don’t hesitate it’s worth every penny.

  5. Dennis Kelly (verified owner)

    Great product would highly reccomend

  6. Kevin (verified owner)

    Just got my bolt carrier group today. she’s beautiful and cycles smoothers then sweet walls of glory.

  7. Geovanny Matias (verified owner)

    Love it love it

  8. Jackie Jones (verified owner)

    Always a great product.

  9. J. Rodriguez

    I’m ordering the nib next for my ar pistol in 300 bo I love my xpb bcg DLC in my rifle I couldn’t ask for any better its PERFECT great work sharps. These are the only bcgs in my life!!!

  10. James Cockrum (verified owner)

    This is by far the the best bolt carrier i own i ordered 2 more. Super smooth.

  11. brucederush (verified owner)

    This is my second BCG from Sharps. The first was the FDE BCG and it’s been running perfectly in my 16″ 5.56 build. I built a 20″ using the PSA CHF FN barrel w/Geissele Rail on an Aero lower. I’ve always wanted the Nickel Boron BCG from Sharps so once they were back in stock I got one. This bolt is awesome! The rifle shoots smooth and soft which helps with the follow-up shot. This is my go-to BCG and I can’t see running anything else in my future builds. The main reason for this review is I did have a minor issue. When I removed the cotter pin for cleaning I noticed it had a bent end. I called Sharps and talked to a lady there about the issue I had.( I wish I had gotten her name) She was very helpful and super nice. Within the week she had sent me replacement pins and a bonus surprise that I wasn’t expecting. Sharps customer service went above and beyond. I was already a fan but this really made a great impression on me. If you ever do have an issue just call them and they’ll take care of you. My next build is going to be a 6.5 Creedmore and I’ll be using the Sharps Xtreme Performance Bolt (XPB) 308 Balanced Bolt Carrier Group with Dual Ejectors.

  12. Paladins Hammer

    I have to say that the no matter which one of the Sharps Xtreme Performance Bolt (XPB) you choose you just can’t go wrong. They have got to be the best BCG on the market today and the chances of anyone coming up with a better one is probably never going to happen. Sharps BCG is so well designed and it functions very smoothly and it does make the recoil of your AR considerably softer. They designed it to be smoother and softer so that your other components will last longer and so you the shooter won’t get beat up so much. The .223/5.56 and the 25/45 Sharps aren’t much of a kicker regardless of what BCG you use but thew 308 line of products can get rather brutal and that’s where Sharps shines in the recoil department. Because their BCG requires less gas to cycle the BCG you can use an adjustable Gas Block and really turn down the gas for a smooth and super soft cycle. And even with a fixed Gas Block the cycle is still smoother and softer than with any other BCG on the market. Sharps did a fantastic job and I give them a BIG thumbs up and 5 stars. They deserve it. BTW, the woman’s name is Kim and yes, she is a wonderful person and she will always do her very best to take care of you. She is the best thing that ever happened to Sharps Rifle Company. She really knows her stuff and will always give you an honest answer. If she doesn’t know the answer, she will be honest and say “I don’t know but I will look into it”.
    Great Products, Honest service and most of all Wonderful people. Sharps Rifle Company. You have my vote

  13. Bradpence (verified owner)

    Best bolt carrier I would true to go hell and back with sharp bolt carriers..

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