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Spikes Tactical 5.56 HPT/MPI Bolt Assembly Up to $10.99 Off w/ Free S&H — 2 models

Spikes Tactical Bolt 5.56 Spikes HPT/MPI Bolt Assembly - Phosphate ST5B500
Spikes Tactical Bolt 5.56 Spikes HPT/MPI Bolt Assembly - Nickel Boron Finish ST5B503
Spikes Tactical Bolt 5.56 Spikes HPT/MPI Bolt Assembly - Phosphate ST5B500
1 of 2 images
Spikes Tactical Bolt 5.56 Spikes HPT/MPI Bolt Assembly - Phosphate ST5B500
Spikes Tactical Bolt 5.56 Spikes HPT/MPI Bolt Assembly - Nickel Boron Finish ST5B503
2 of 2 images
Spikes Tactical Bolt 5.56 Spikes HPT/MPI Bolt Assembly - Nickel Boron Finish ST5B503

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Questions & Answers
Are the gas rings on it like in the picture? Expert Answer

The gas rings on them are silver.

by Ryan Tarczynski, Gear Expert, July 16, 2021
See 2 More Answers
Does this bolt come with anything else besides the actual bolt, like a pin?

This comes with only the bolt.

by Mike B., Verified Owner, February 3, 2021
View All Q&A You Have a Question? Ask!
Customer Reviews
Helpful Positive Review
Best Value for a bolt I trust my life to. by Beans, Verified Owner, October 22, 2021
1) I trust Spikes Tactical. I trust the people there. Every purchase and interaction leaves me the same resounding image. Consummate Pros. I’m coming back to phosphate after testing NiB and Nitride coatings. I like advanced coatings with added lubr...
Read More...
1/3 found this helpful
Helpful Positive Review
Inspect it by Eric B, Verified Owner, December 31, 2020
Did an inspection of the bolt. Great coating, MPI tested, etc. But... when I pulled off the extractor, the extractor pin had to be hammered out. Figured out that it was a bad/ wrong size spring, and the extractor had been forced on. Replaced with the...
Read More...
5/5 found this helpful
Most Recent Reviews
More of a compliment than a review by lynmack, Verified Owner, July 23, 2021
I purchased this bolt assembly and a few other items that went with it during the midst of the covid craziness. There was nothing available for ar15 type weapons at the time and I was overjoyed to find a few parts in stock. There was some confusion i...
Read More...
Read All 3 Reviews
2 Models Available
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made-in-usa-flag Made in USA

Help support American manufacturing! Marked models of this product have gone through rigorous review and been certified by the manufacturer as Made in the USA.

Product Info for Spikes Tactical 5.56 HPT/MPI Bolt Assembly

A high-quality bolt is a must in any AR-15. Whether you need a spare bolt or are looking to upgrade an existing rifle, look no further than these Bolt Carrier Groups, available with a Black Nitrite or Nickel Boron finish. This is the same bolt Spikes Tactical uses in their builds.image

Specifications for Spikes Tactical 5.56 HPT/MPI Bolt Assembly:

Manufacturer: Spikes Tactical
Caliber: 5.56x45mm NATO
Condition: New
Country of Origin: USA

Features of Spikes Tactical 5.56 HPT/MPI Bolt Assembly:

  • Mil Spec Bolt:
  • Phosphate Finish
  • 158 Carpenter Steel
  • Shot Peened
  • High Pressure Tested (HPT)
  • Magnetic Particle Inspected (MPI)
  • Mil-Spec Extractor
  • 8620 Tool Steel
  • Phosphate Finish
  • Extractor Spring
  • Black Extractor Insert
  • Viton O-Ring

Package Contents:

  • Spikes Tactical 5.56 HPT/MPI Bolt Assembly

Spikes Tactical 5.56 HPT/MPI Bolt Assembly Orderable Models

List of Orderable Models

  • Spikes Tactical Bolt 5.56 Spikes HPT/MPI Bolt Assembly - Phosphate, ST5B500 , MPN: ST5B500 , UPC: 855319005471 , Code: 2A8-ABA-HMBA-ST5B500
  • Spikes Tactical Bolt 5.56 Spikes HPT/MPI Bolt Assembly - Nickel Boron Finish, ST5B503 , MPN: ST5B503 , UPC: 855319005488 , Code: 2A8-ABA-HMBA-ST5B503

Spikes Tactical 5.56 HPT/MPI Bolt Assembly Unavailable & Discontinued Models

List of Unorderable Models

  • USED Spikes Tactical Bolt 5.56 Spikes HPT/MPI Bolt Assembly - Nickel Boron Finish, ST5B503, EDEMO1, Used, Condition Fair, Scratches , MPN: ST5B503-EDEMO1 , Code: 2A8-ABA-HMBA-ST5B503-EDEMO-SC-D
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Last updated 2026-10-09 UTC.