There are few parts of an AR that are as important as the bolt carrier group. While the standard Mil-Spec bolt carrier does its job well and has for decades, new improvements in technology and materials have come along and revolutionized the design.
When looking at the Best Bolt Carrier Group to use for any AR-15, there a number of factors one must consider. Like many aftermarket pieces for ARs, much depends on what the intended purpose of the weapon is, what sort of budget you have to work with, firing frequency, and of course aesthetic appeal. However, before we delve into the finer points, lets first understand what a bolt carrier group is and what sorts of duties it performs.
What is the purpose of a bolt carrier?
The physical bolt carrier itself houses the bolt, gas key, firing pin, extractor, and cam pin. This unit, as a whole rides inside the upper receiver. Its main purpose is to strip a round from the magazine, chamber it, cycle the “action”, eject the empty brass, and reset the hammer all in one cycle. The BCG is easily the most critical component of the weapon and has a large part in deciding whether a gun is reliable or not. It truly is the heart and soul of the weapon.
The BCG, when working with the buffer, buffer spring, and tube creates the necessary motion to cycle the action as well as determining the degree of muzzle rise and recoil the shooter will experience.
The THREE types of BCGs
For the most part, bolt carrier groups come in three different options. M-16, AR-15 and lightweight. Both the M-16 and AR-15 share many of the same characteristics, but each has its own purpose and function.
The M-16 version is heavier and has a longer, full size rear section. The increased mass remains in battery longer and is designed to withstand the abuse of fully automatic fire as well as match grade guns. The AR-15 BCG on the other hand is designed for semi-automatic fire and cycles faster, usually because of its lighter weight.
Lastly, the lightweight/Low Mass BCG is a built for ultra-light competition guns that require a number of other parts in order for it to function reliably. Precision tuning is also needed in order for it to run at its best.
Why upgrade to a better bolt carrier group?
Now that you know what a bolt carrier is and what the three different types are, why do you need to upgrade? Depending on how much you actually shoot and what sort of demands your rifle is expected to achieve will usually determine what sort of BCG you will select if you choose to upgrade.
There are four primary reasons to upgrade.
• Improved Reliability: A heavier steel BCG increases the gun cycle time and reduces stress on the spent brass. This sort of benefit is for those who reload. The weight also helps in the rifles ability to digest more types of ammunition with very minimal adjustment. A steel BCG is what the military and law enforcement mainly use in their service rifles because they can handle a large volumes of fire.
• Improved Durability: Titanium and or coated/plated carriers bring a higher level of durability when compared to steel BCGs. Titanium is lighter and stronger than steel and can withstand a higher amount of heat and extreme pressures when using hotter loads. Something to keep in mind though is titanium is more expensive and commands a higher price. A coated/plated BCG has a slicker surface and is much easier to clean, usually requiring nothing more than wiping it down with a cloth.
• Increased Speed: Choosing a BCG that utilizes titanium or anodized aluminum decreases the weight and mass and therefore allows the firearm to cycle at a higher rate compared to the heavier steel in semi-auto fire. While weapon control is gained more through practice than anything, this higher rate of fire can prove beneficial in the competition field.
• Improved Action Smoothness: When using a BCG with a Nickel Boron, Diamond-Like Carbon coating or Black Nitride, you will enjoy a slicker surface and reduced friction which creates a smoother action as a whole.
Best AR-15 Charging Handles
||Top Selling AR-15 Bolt Carrier Groups
||Rainier Arms AR-15 Precision Match Grade BCG - nitride
||BCM Bolt Carrier Group - Auto MP
||AR-15 Bolt Carrier Group - Nitride
||Noveske Enhanced Bolt Carrier Group
||Sharps Rifle Co AR-15 Xtreme Performance
||F-1 Firearms 5.56 DuraBolt Bolt Carrier Group
||Rainier Arms BCG - AR-15 Precision Match Grade - stainless
||V Seven AR-15 Titanium BCG Complete Ionbond Finish
||Faxon Gunner BCG Ultra-Light Bolt Carrier Groups
||Shooting Innovations AR-15 LMB Low Mass BCG
2019 Product Review: Top-Selling Charging Handles
1. Rainier Arms AR-15 Precision Match Grade BCG - Nitride
The Rainier Arms Precision Match Grade Phosphate BCG - 5.56 Nitride is machined and finished to a higher standard to meet and exceed all Mil Spec. It is machined using the most precise equipment in the industry. The bolts are MPI/HP tested & Marked to give you ultimate confidence in your weapon system.
- Full Auto Carrier
- SAE 8620
- Heat Treated
2. BCM Bolt Carrier Group - Auto MP
Bolt carrier group (auto version) for your AR15, M16, or M4. Parkerized exterior and chrome lined inside carrier. Machined to USGI specifications. This M16/M4 carrier includes the proper Mil-Spec gas key. Gas key is chrome lined and heat treated per GI specifications. Gas key is secured to carrier via USGI domestic mfg Grade 8 fasteners and properly staked per Mil-Specs. These properly hardened parts insure a strong staking and proper gas system functioning.
The bolt assembly is machined from the correct Mil-Spec Carpenter No. 158 steel, shot peened for increased strength, includes tool steel machined extractor and ejector, BCM Extractor Spring, and is HPT (High Pressure Tested) and MPI (Magnetic Particle Inspected).
Prior to shipping, all BCM Bolt Carrier Groups are test fired for function. As such, the Bolt Carrier Group will show handling marks consistent with these quality control procedures.
3. AR-15 Bolt Carrier Group - Nitride
Features a shot-peened bolt for increased surface strength and durability, and an extractor booster to ensure reliable cycling during rapid semi-auto or full-auto fire. Includes Colt M16 firing pin upgrade. Each assembly is magnetic particle inspection tested to ensure it’s free from imperfections that can lead to premature failures. Properly staked gas key prevents gas leakage that can lead to short stroking.
• Carrier: 8620 Tool Steel-(M16 full shroud)-Heat Treated, Case Hardened
• Gas Key: Tool Steel-Attached using Grade 8 Hardened Fasteners, & Staked.
• Cam Pin: 4140 Steel
• Extractor:Tool steel-shot peened
• Coating: Melonit
4. Noveske Enhanced Bolt Carrier Group
RCA Black Nitride Bolt Carrier Group.
Noveske marked with a black nitride finish. Carrier features 8620 steel with 9310 bolt and tool steel extractor and cam pin.
Much more than typical Parkerizing, phosphating or black oxide. Blacknitriding is a thermal chemical diffusion of nitrogen and carbon into the surface of the steel. This process increases wear-resistance, fatigue strength, corrosion resistance, lubricity and cosmetic appeal.
5. Sharps Rifle Co AR-15 Xtreme Performance Bolt Carrier Group XPB
The Sharps Xtreme Performance Bolt (XPB) Carrier Group Complete is precisely machined from S7 tool steel. The XPB undergoes a 24-hour thermal cycle proprietary heat treatment and is finished with DLC (Diamond Like Carbon) Coating. The XPB Carrier Group Complete displays the SRC logo machine cut and visible when the ejection port door is open. The XPB fits standard AR-15/M16/M4 rifles chambered in .223/5.56mm, 25-45 Sharps and 300 Blackout calibers.
• Bolt: S7 Tool steel, shot peened and DLC coated
• Bolt Carrier: S7 Tool steel, shot peened and DLC coated
• 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 firing pin 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
When you look at just how important the bolt carrier group is in your firearm, it is hard to deny the fact that it should be the best, more durable part of the rifle. Yes it can add expense to your build, but it will add a lot of longevity to your firearm in the long run. Why struggle with a unreliable weapon when you can just pick up a few things to make yours run better than ever. The phrase “buy once, cry once” may be overused at times, but it still rings true when you are considering upgrading your Bolt Carrier Group.