Category Archives: AR-10 Parts

Why Anti-Tilt Buffers Matter

Did you know that all AR-15 and AR-10 bolt carriers tilt down at the rear end as the action cycles?  This phenomenon called “carrier tilt” became widely known when piston driven ARs became popular because in some cases it was severe enough to cause obvious damage to the gun in short order.  On the piston guns, the gas piston strikes the solid carrier key on top of the bolt carrier to drive it to the rear.  This strike at the top of the carrier causes the lower, rear of the carrier to tilt downward as it starts to move which makes it contact the lower portion of the buffer tube (receiver extension).  On most standard bolt carriers, the rear of the carrier is completely unsupported and there is enough play in the tolerances between the carrier guide rails at the front and the upper receiver to allow this movement.  So a lot of piston guns were getting noticeable wear in the buffer tube or at the front edge of the buffer tube after just a few hundred rounds and customers didn’t like this.  To fix the problem, piston gun manufacturers enlarged the profile of the rear end of the carriers and beveled them or machined “skids” into them so they couldn’t tilt as far and if they did impact the buffer tube, the wear wouldn’t be as significant.  This is a partial solution for the piston guns, but some tilt may still happen depending on the tolerances and there is a bit of movement before the carrier gets inside the buffer tube where the skids can help.


What most AR shooters don’t realize is that the Direct Impingement Guns or “Gas Guns” also suffer from some carrier tilt.  It usually isn’t as much so it may not result in any buffer tube wear or other obvious visual signs.  But the gas still hits the carrier at the top, just as it does on a piston gun causing the rear to tilt.  It’s impact just isn’t as abrupt as a piston is, so the tilt isn’t normally as severe.  But there is still the same amount of play in the carrier to receiver fit to allow for tilt on a gas gun and it still can have negative consequences even if it isn’t damaging your buffer tube.  When the carrier tilts as it starts moving to the rear and unlocking the bolt, it is putting extra stress on the bolt which is still locked into the barrel trying to turn and pull through the locking lugs.  This stress can eventually cause the bolt to crack and break, normally at the locking lugs or at the cam pin hole, which are two of the thinnest and most stressed points on the bolt.  So that’s a serious problem right?  If your bolt breaks, your weapon is down hard until it can be replaced.


So how do we solve this problem?  The piston gun manufacturers modified the design of the rear end of the carrier as mentioned above.  That’s a good thing.  Many shooters carry a spare bolt in their pistol grip which is a prudent idea in case one does break.  Some of the top tier companies started making their bolts out of tougher steels and doing more quality control on the bolts which raised the price a bit, but is a good thing for the gun owner and does reduce breakage.  But in my mind, a real solution needs to get rid of the carrier tilt in the first place and remove these stresses from the operating system altogether.  That’s where the anti-tilt buffer comes in.  An anti-tilt buffer has a protrusion at its front end that extends into the hole in the rear of the bolt carrier.  It supports the bolt carrier through it’s entire cycle not allowing it to tilt more than a few thousandths of an inch.  So the buffer tube doesn’t get any wear, the bolt doesn’t endure any stresses from the carrier tilt and the entire system cycles more smoothly because there is less friction.  All in all this is a great solution.  As you should know, there’s always a trade off somewhere for these advantages, so what’s the down side of an anti-tilt buffer?  Since the buffer is holding onto the rear of the carrier, you can’t just pull the rear takedown pin and shotgun open the action.  You have to pull both the rear and the front takedown pins and pull the upper receiver completely off of the lower receiver to open the action.  Not too bad right?  Some folks don’t like this because they are so used to opening up the action that way, but it’s a pretty small trade off for a smoother running, longer lasting operating system if you ask me.  Besides, now days you can find all sorts of easy pull take down pins to make pulling them both a breeze.  So if you want the smoothest running, longest lasting operating system you can have take a close look at some anti-tilt buffers.  The CTS Aktive buffers are some of the best.

AKTIVE Buffer for Fixed Stock AR-10 and AR-15

Without a doubt, the AKTIVE Buffers by CTS Engineering would be one of my first picks for any AR-15 or AR-10 rifle with a fixed stock.  They have a solid stainless steel buffer body with an overall weight that has been finely tuned for excellent performance in those specific platforms.  But even more importantly, they have a shock absorbing piston on the front end and a far superior bumper on the rear end for a dual stage buffering action.  This action really does make a noticeable difference in the smoothness and recoil of the weapon.  I’ve seen a lot of buffers over the years and this is probably the best bang for the buck of any buffer on the market.  The AKTIVE buffers are made in both a standard and an anti-tilt version in so you can have every feature you could want on a buffer.  They run as smoothly and quietly as any buffer system on the market, so if you are thinking about using a suppressor, they are a great choice for that too.  Heavy loads or light loads?  No problem.  Match them up with a tuned, ground and polished JP buffer spring for the quietest operation possible.  You will be very pleased, I assure you that.  If you have a fixed stock AR type rifle, this is one of the best upgrades you can buy for it.


CTS AKTIVE Buffer for AR-15 and AR-10


CTS Engineering has developed an innovative new line of buffers for AR-15 and AR-10 series rifles, carbines and pistols.  Their buffers, called AKTIVE buffers, are made with a stainless steel buffer body and a 2-stage buffering action to reduce recoil and muzzle movement and smooth out the operation of the action.  The aktive buffers have a hard polymer piston head that compresses an elastomer shock absorber inside the buffer as the bolt carrier and buffer impact the rear of the buffer tube.


It also has an improved rear bumper that has superior shock absorption than a conventional rear bumper.


The buffering actions on the front and rear of the buffer work in tandem to soften the blow and reduce shock and recoil that comes from the bolt carrier.  The piston head also works to dampen the forward impact of the bolt carrier going into battery as well.  Since it is acting as “sprung weight” instead of “dead weight”, it doesn’t feel  like as much of a slam forward as with an equal weight conventional or solid heavy buffer.


When shooting with an AKTIVE buffer compared side by side to a conventional buffer, it feels like it does soften the recoil to the shoulder enough to notice and the sights don’t move off target as far.  It feels softer recoiling than conventional buffers, H2 buffers, tungsten powder buffers and solid heavy buffers.  Additionally, the cycling of the action as a whole just feels smoother.   A further benefit of these buffers is that they dramatically reduce spring noise and vibration for a quieter running system which most AR shooters would agree is a nice touch.   They work well with factory buffer springs or upgraded aftermarket springs.


Aktive buffers come in a wide variety of models including standard carbine sized 3.25″ buffers, AR-15 rifle length buffers, AR-10 rifle length buffers and even Vltor A5 compatible buffers.  AR-10 carbines that use a 3.25″ buffer (such as Sig, LWRC and Armalite) can use the AR-15 carbine Aktive buffer as long as it is paired with an AR-10 carbine buffer spring.  Additionally, they are available in standard and anti-tilt configurations for every model.  The anti-tilt versions have a protrusion at the front of the buffer that extends about a tenth of an inch into the rear of the bolt carrier to support it and keep it from tilting during cycling.  This is especially helpful with piston guns, but all ARs have some degree of carrier tilt and this helps to smooth it out.  The polymer piston head that is in contact with the buffer tube is quiet and prevents wear on the buffer tube.  Having the rear of the bolt carrier supported makes a lot of sense not only to prevent buffer tube wear, but to put less stress on the bolt, cam pin, gas tube and upper receiver that would all be effected by carrier tilt.   The anti-tilt versions cost the same as the standard versions, but does require that you pull both the rear and front take down pins in order to open the action.  Some folks don’t like not being able to break open their action like a shotgun, but pulling two pins instead of one seems like a small price to pay for better operation and less wear.  But whichever suits your fancy, there’s a model for you.  Once you grasp all the features and benefits these buffers have to offer, the $65-70 price range seems like a  pretty fair deal.  They are available for purchase at

Primary Weapons Systems (PWS) CQB 30 Compensator

CQB pic

CQB, or close quarters battle, is all about precision, speed, and aggressiveness. The shock of attacking operators swiftly penetrating OPFOR’s sanctum is essential to any successful mission. Yet, without the proper equipment, it is nearly impossible to maintain a high level of operating efficiency. Long barreled rifles would get caught on obstacles, unnecessarily heavy weapons would exhaust the shooters, and compensators would redirect the muzzle blast to the sides, often times right into the face of a team member. The vital aggressiveness can soon become bogged down to a slow grind. Recognizing this, weapons have evolved to adapt to the new situation. The extremely confined nature of the urban environment necessitates the use of small, compact weaponry to allow operators to easily maneuver around obstacles while keeping the all important momentum in their favor.  These shorter weapons come with their own disadvantages that need to be mitigated.


Though many of us will never be placed in an urban jungle, playing a deadly game of cat and mouse with enemy a skilled enemy, Primary Weapons System’s CQB 30 is nevertheless shockingly practical for the consumer. The military application is not far from a common civilian necessity: home defense. Already designed for a severely restricted environment, the CQB 30 is perfect for home defense for the very same reasons it excels clearing rooms. Few realize the absolutely defining noise firearms make inside closed areas, especially with short barreled rifles (SBRs). Combine the noise with the blinding three foot flames exploding out of your rifle, and you will be lucky to see or hear anything after the first few rounds. These troubles are especially evident with smaller weapons like AR15 pistols or SBRs. The CQB 30 Compensator eliminates both of these problems by redirecting the muzzle blast forward, away from your ear drums, and suppressing the flash. It also slightly delays the gas expulsion, which results in less recoil. In essence, the PWS CQB allows the shooter to maintain his focus on the target, without being distracted or disoriented by excessively loud concussive blasts or bright muzzle flashes, giving you the control of the situation and preventing unnecessary harm to a family member who would have otherwise been hit by the blast. This directly translates to greater personal preparedness and a massive advantage for the gun owner in a home defense situation.


Adapted from the PWS CQB 556, which serves the smaller .223 caliber, the CQB 30 was tailored to 7.62mm bullets, which can support 7.62x51mm (.308), 7.62×39 and .300 Blackout as long as they have 5/8×24 threads on the barrel. Weighing in at a solid 7.2 oz, the CQB is made from high quality materials which are covered by a lifetime warranty. This added weight gives the operator increased control, mitigating the difficulty many experience controlling SBRs, on top of the obvious benefits of redirecting the concussive blast and suppressing the flash. Furthermore, the PWS CQB 30 is only two and a half inches long, perfect for shorter barrel lengths for which it was designed. For these reasons, the Primary Weapons System CQB 30 is rapidly becoming one of the most popular compensators on the market today.  Perfect for AR pistols and SBRs but also providing significant advantages to longer barreled carbines as well.  Overall, the Primary Weapons System CQB 30 is an amazing piece of hardware with invaluable benefits to both the firearms enthusiast and home defense minded shooter and is highly recommended.

Why Would I Want an Adjustable Gas Block?

Adjustable gas blocks come in a number of forms.  Some have 3 pre-set positions that the operator can select like “normal”, “adverse” for when your gun is really dirty and you don’t have time to clean it, and “off” for when you want to manually cycle the action.  Some have settings for “suppressed” for when using a sound suppressor.  These are most common on military rifles and one of the earliest was the Belgian FN-FAL.  It’s gas block had a nut that could be unscrewed one click at a time which gradually exposed a gas port which would vent excess gas pressure.  This threaded nut concept is useful because the operator could set it exactly where he wants it for his gun and his ammo instead of just having a “normal” or “adverse” setting.  This ensures the gun is set to where it will run reliably without running excessively hard causing more recoil and wear on parts than necessary.

FAL gas regulator


This concept has made it into the aftermarket parts industry as well for guns like the M1 Garand and AR-15 where adjustable gas plugs or gas blocks can be installed by the operator or a gunsmith.  I’ll focus on the AR-15 adjustable gas blocks since they have become quite popular for those building custom guns or upgrading their current rifle.  A few years ago, when adjustable gas blocks were relatively new on AR-15s, they simply consisted of a gas block with a screw in the side that would gradually cut off the gas flow from the barrel to the gas tube as you screwed it in.  This is the simplest type to manufacture and quite a few companies make them now.  Some of the most popular examples of these are made by JP Enterprises which have been around for years.  PRI has also made one for a while and Wilson Combat and several others have recently come out with their own designs. These work well, but the screw isn’t secured in any way, so it could technically drift since it’s not locked in place.  In practice, carbon builds up in the threads and normally keeps the screw setting stable.  This style is still widely used and liked today, especially for competition shooters.


But many shooters want things that are locked down and can’t come loose during a competition or a self defense situation no matter what.  So this led to adjustable gas blocks with lockable settings.  Lockable settings can consist of a second screw that is tightened into the side of the adjustment screw to lock it into position once you got the setting where you want it.  This is a simple approach that works and is used on some high quality gas blocks like those from Seekins Precision.  The Seekins Precision Adjustable Gas Block uses a brass locking screw to secure the set screw.  The most recent development are those with spring loaded detents which click into position every quarter turn as you adjust the set screw.  Popular examples of these are made by Syrac Ordinance and SLR Rifleworks.  The nice thing about this is that all you have to do is turn the set screw with an Allen wrench and it locks in place automatically as you go, so you don’t need to tighten a second screw and it stays very secure on the setting you want and it’s easier lock into position while under a handguard.  Additionally, with audible click settings, you can keep tract of settings and adjust it by a known number of clicks for a certain type of ammo for example.



So what can you expect to get from using and adjustable gas block on your AR-15 or AR-10 type rifle?  Many guns come over-gassed from the factory and run the bolt carrier group harder than it needs to, so it can be tuned down a bit to feel softer recoiling while still functioning properly.  You also have the option of trying a different buffer system and optimizing the gas flow to work with that buffer.  One of the most effective ways to use an adjustable gas block is to pair it with a lightweight bolt carrier and then tune down the gas to get the speed and reliability right.  This makes for less reciprocating mass for less movement of the gun as it cycles and quicker sight picture recovery for the next shot.  This concept was popularized by JP Enterprises as the Low Mass Operating System or LMOS and now several other manufacturers are making light weight bolt carriers as well.  A fringe benefit of tuning down the gas is that it may run a bit cleaner with less gas going through the bolt carrier.


Not all ARs can benefit from and Adjustable Gas Block since some don’t have too much gas coming out of the gas port and you wouldn’t want to tune it down further.  But for guns running very hard, or for those who want to use a light weight bolt carrier, it can be very useful.  One thing to remember is that you can’t increase gas pressure with an adjustable gas block.  The full pressure is determined by the gas port location and size in the barrel.  An Adjustable Gas Block can only tune down gas pressure.  But they do have a useful place in firearms design and are something you might want to consider if building or customizing an AR type rifle.

Precision Rifle Compensator (PRC) by Primary Weapons Systems

PWS PRC 5We just added a new video to our YouTube Channel highlighting PWS’s PRC.  It’s a pretty nice compensator that goes great with Remington Bolt Actions and AR10’s.

If you are interested in getting one , they are available at