In 1959 the ArmaLite AR-15 was born, and 60 years later it’s popularity only continues to grow. With advancements in ergonomics, controls, and handling, it is one of the most robust firearms platforms on the market today. With the help of legendary firearms designer Jim Sullivan (one of the original AR-15 designers), SureFire set their sights on bringing the AR platform further into the 21st century with the SureFire OBC – Optimized Bolt Carrier.
SureFire OBC – Optimized Bolt Carrier
The SureFire OBC comes neatly packaged with both carrier, buffer, and buffer spring. This way you get everything you need to get your AR carbine up and running with the new carrier.
Taking apart the OBC is exactly the same as your factory AR-15 Bolt Carrier Group. Simply remove the retaining pin, firing pin, cam pin, and then bolt. I was quick to notice the new very slick anti-friction coating. Even with this coating, I recommend lightly oiling the OBC before first use. AR-15’s run best with all their moving parts lightly oiled.
What’s the difference?
The SureFire OBC was designed to increase the all-around reliability of the AR platform. In order to accomplish this, some key changes were made to the original design. While at first glance it may look like a factory BCG, the SureFire OBC differs vastly.
The OBC (pictured bottom) features a lengthened cam slot at the front of the carrier. This delays the unlocking of the bolt and allows 15% more of the spent gasses to be expelled out the bore. This should create less gas port noise, especially when using a suppressor.
In order to give the bolt a longer stroke, the gas carrier key was shortened. Using a larger single bolt design, the SureFire OBC aims to maintain the overall reliability, also while giving the bolt an overall 60% increase in stroke. This increase in return bolt speed is designed to feed ammo more reliably.
At the rear of the carrier is a new balanced counterweight that works in three phases. First, it delays the unlocking of the bolt as mentioned above. Second, at the end of the stroke, the weight holds the carrier back to provide the added return velocity. Third, the counterweight at the rear acts to nearly eliminate bolt bounce when the bolt slams shut thus reducing wear and increasing reliability.
At The Range
As the OBC shipped with a carbine length buffer and spring, I thought the best place to start would be on this 16″ Noveske. The first thing I noticed with the OBC was the recoil impulse. It’s all smoother and has more of a roll rearwards and forwards feel. Noticeably different compared to a factory BCG. I had multiple people shoot the rifle with the factory BCG and then the OBC, and all reached this conclusion.
Where the OBC really shines is with the addition of a silencer. If your gun is overgassed the OBC won’t magically fix this. It will, however, allow more of those gasses to escape out of the bore. This lower gas port noise results in a far more pleasant to shoot suppressed AR-15.
The increased dwell time is actually long enough that this slow-motion footage was able to capture the gas being expelled from the bolt. Pretty cool stuff.
Before you ask, yes, you can use the OBC with other buffers. You don’t need to use the SureFire buffer, but I like that they included it.
I found the OBC to be most at home on this 20″ post-sample M16 clone. With a rifle length gas system and buffer, the cyclic rate is already slower. The OBC then slows the cyclic rate down even further (thanks to the counterweight). All of this makes for a very smooth easy to shoot rifle.
However, if rifle length gas systems aren’t your forte, I did test the OBC on various SBR length uppers. Though almost 2,000 rounds of testing, the OBC never flinched. Durable and dependable. Yes to both.
Pro’s & Con’s
I have yet to let someone shoot the OBC who didn’t agree it was an all-around more pleasant to shoot experience. The gas port noise reduction is stellar, and I can’t wait to meter this against a factory BCG. Recoil is also noticeably smoother compared to a factory AR-15. The impulse is more of a slow push compared to the snappy factory AR recoil you might be accustomed to. On top of all of this, I noticed all the host weapons ran much cleaner through testing. This I’m sure will aid in reliability in the long run.
The biggest downfall for the OBC would have to be its cost. At $399.00 MSRP the OBC isn’t cheap, and it’s a luxury that most AR owners might be willing to look past. The OBC also weighs slightly more than your mil-spec BCG at 13.8oz compared to the mil-spec weight of 11.6oz. Lastly, with a price tag of $400, I’d really like to see some different buffer length options in the future. I know we live in a carbine world, but a rifle length buffer option wouldn’t hurt.
TFB Review: The New SureFire OBC – AR-15 Optimized Bolt CarrierAfter testing the SureFire OBC for over a month I can safely say it’s my favorite aftermarket BCG on the market. The $400 MSRP it’s a luxury for most AR-15 owners. Do you absolutely need it? No. Will you want it? Yes. However, for those complaining about a stale market for AR-15 accessories, this is the price of real innovation. SureFire did their homework on this one, and having Jim Sullivan design the OBC was a stellar move.
So would I buy one of these? Absolutely, and now I feel I need 4-6 more of them. Because honestly, it’s all I want to shoot now.
Published on Sep 19, 2019 – SureFire
The SureFire OBC is designed to greatly increase the reliability of an M4/M16/AR variant during both unsuppressed and suppressed firing. The OBC comes as a package with the OBC bolt carrer group as well as buffer and buffer spring. This patented design makes numerous improvements to the standard Mil-Spec full-auto bolt carrier group starting with delayed unlocking of the bolt during the firing sequence. This delayed unlocking is a result of a lengthened cam pin slot and our neutrally balanced counterweight. This delay allows expanding gases more time to exit the bore, lowering chamber pressure by 15%, which not only reduces wear and tear on parts, but also reduces back-pressure gases exiting the ejection port. Next the shortened gas carrier key in conjunction with shorter buffer allow a 60% increase in stroke.
This increase in stroke gives the magazine more time to feed, which can be essential as gas ports erode and magazines become dirty from austere environments. This additional stroke also provides smoother and more reliable feeding due to increased inertia when the OBC picks up a round from the magazine. The previously mentioned neutrally balanced counterweight works three times in the cycle of operation. First the counterweight delays unlocking, as mentioned before. Secondly, the counterweight keeps the carrier group to the rear for additional time allowing more time for reliable feeding of ammunition from the magazine, and nearly eliminating bolt-over-base malfunctions.
Lastly, this counterweight improves carrier and barrel extension lock-up, nearly eliminating bolt bounce. The OBC also reduces felt recoil, allowing for better tracking of sights and more control of the weapon when firing. Coated with an advanced anti-friction coating, the OBC resists friction during use and makes cleaning easy. For the ultimate in reliability, choose the SureFire OBC.
SureFire Optimized Bolt Carrier – Product Page
- Neutrally balanced counterweight automatically reduces cyclic rate, negating the need for switch or setting adjustments.
- Improved cam path delays unlocking, allowing the chamber pressure to drop another 15% which permits more gasses to exit the bore
- Nearly eliminates bolt bounce
- Long stroke design improves reliability, allowing ammunition more time to feed properly
- Utilizes Mil-Spec bolt and components
- Anti-friction coating resists corrosion and makes cleaning easy
- SF-OBC-556 comes standard with Optimized Bolt Carrier, Long-Stroke Buffer, and Improved Buffer Spring