AO Precision C158 SP/HPT/MPI 5.56 Bolt Carrier Group Black Nitride - 5877
In stock
AO Precision has provided BCGs to large military contractors such as FN America and large commercial retailers who re-brand and sell these at a considerable mark-up. You can now get these directly from AR15Discounts.com and save big!
Bolt
- Machined from Carpenter Technology No. 158 alloy.
- Heat treated
- Shot peened per ASTM B851/SAE AMS2430S
- Individually High Pressure Tested (test fired)
- HP proof testing, 100% using a high pressure M197 or SAAMI commercial equivalent, without evidence of failure
- Individually Magnetic Particle Inspected after Initial Test Fire
- Black Nitride Finish
Extractor
- 4140 Steel per ASTM A108, cold drawn and stress relieved BHN 187-22
- Phosphate Finish
- Extractor Spring
- Black Extractor Insert
- Viton O-Ring
Carrier
- Machined from AISI 8620 aircraft quality alloy per ASTM A108/A322-13
- Full Mass M16 Profile
- Stress Relieved
- Black Nitride Finish
Gas Key
- Machined from 4130 chromoly steel alloy per ASTM A108/A322-13
- Grade 8 Hardware
- Properly Staked
- Hard Chrome Internal
- Permatex sealed
| Weight | 11.408 oz |
|---|---|
| Bolt Material | Carpenter 158 Steel |
| Cartridge Compatibility | .223/5.56 NATO/.300 BLK |
| Finish | Salt Bath Nitride |
| Carrier Profile | M16 |
| High Pressure Tested | Individually HP Tested |
| Magnetic Particle Inspected | Magnetic Partical Inspected |
| Platform | AR-15 |
| Bolt Finish | Mag Phosphate |
| MPN | 5877 |
| UPC | 5877 |
Compliance
NFA (National Firearms Act) compliance is crucial for legal ownership and transfer of regulated firearms and accessories like short-barreled rifles, suppressors, and certain types of ammunition, ensuring adherence to federal regulations to avoid legal penalties and ensure responsible firearm ownership.
Customer Reviews
- Reviews
- Questions
US
Great BCG, but could be finished better.
This BCG has worked well for me thus far. It has a bit of machining marks on the inside; however, these really don't make a functional difference. Certainly worth the price when they go on sale!
USWorks just fine.
Had no issues at all.
USAO Precision C158 SP/HPT/MPI 5.56 Bolt Carrier Group - Black Nitride
Have not assembled the firearm yet, but it appears very nice; finish is dark and even with no unsightly tool marks. There was no discernible machining residue. After lubrication, manual operation was very smooth; this appears to be a high quality bcg.
USGreat Value BCG
I purchased this BCG for a 11.5" AR pistol build in 5.56 with a Ballistic Advantage nitride Government barrel that has a taper pinned F marked front sight with bayonet lug and SB Tactical SBA3 brace. I wanted the bolt carrier group to match the finish of the barrel and nitride A2 flash hider. The fit and finish is nice and it is made of proven quality materials. I did upgrade the ejector with a JP enhanced version strictly for reloading purposes as it is a little easier on the brass. That is a nice upgrade to any bolt, but definitely not a must have by any means. I am happy with my purchase and managed to even snag it up on sale.
USBCG
Looks nice, headspace correctly, shoots good at a fair price. What else does a Bolt carrier Group need to do?
