Welcome to the Addax Tactical FAQ (Frequently Asked Questions) page.

This page is set up to help answer many of the questions we are normally asked regarding our products and services.

Q) Did Addax Tactical develop a new Piston System used on the Addax ZK Piston Uppers?

A) Yes, we have developed a new short stroke piston system for our ZK Piston Uppers, and we offer the ZK Piston Uppers in limited production runs. 

Q) Does Addax Tactical still use any of the PWS Piston System?

A) As of October 2010, we no longer use any of the PWS Piston Systems (Short Stroke or Long Stroke).

Q) Gas Piston vs. DI AR... Which is Better?

A) Over the past few years we have been asked this question numerous times, and the best answer we can provide is that both DI and Gas Piston AR's work, but they both have different operating principles.

Gas Piston has one key advantage over the standard DI gas AR, and that is it will blow out most of the hot gasses and carbon at the gas block or out of the Piston Tube vs. carrying these into the upper receiver and bolt carrier as does the DI AR.

The Gas Piston AR will run cleaner and cooler inside the upper receiver compared to the DI AR.

If you are shooting with a sound suppressor, a Gas Piston AR will be slightly cleaner vs. a DI AR inside the upper receiver and around the bolt carrier group.

DI AR has several key advantages over Gas Piston AR's, and they are:

1) Basic Parts commonality such as bolts, bolt carriers, upper receivers, gas blocks, and gas tubes.
2) Less Moving Parts
3) Cost Less

We feel it is up to the individual consumer to decide which key factors between DI vs. Gas Piston are important to them in their decision making process, and Addax Tactical offers both DI and Gas Piston AR solutions to our clients.





Q) What is the difference between Long Stroke and Short Stroke Piston Systems?

A) Gas-Operated Reloading-Wikipedia We find that there is some good information here to help answer this question.


Q) What is Carrier Tilt?

A) Carrier Tilt is the bolt carrier group moving down and to the rear or tilting during operation of the piston system pushing the bolt carrier into action.

Carrier Tilt is created due to the off axis thrust or push of the piston rod to the bolt carrier (Piston Rod pushing the top end of the carrier into operation).

Signs of Carrier Tilt (where the carrier is rubbing too hard against the edge of the buffer tube) can also be caused by an out of spec. buffer tube, or a miss-aligned upper and lower receiver where the carrier is not properly transitioning between the upper receiver and the buffer tube.



Q) Will Carrier Tilt damage my rifle?

A) The only part that we have ever seen really affected by carrier tilt is the front end of the buffer tube, and buffer tubes can be easily replaced.

There are newer types of buffer tubes specifically designed for piston driven AR's from PWS and POF that have extended leading edges to help capture the piston carrier throughout it's travel to help virtually eliminate the effects of carrier tilt.

 PWS Enhanced Buffer Tube

POF Enhanced Buffer Tube

There are also Anti-Tilt Buffers available from (Slash) Heavy Buffers.

Carrier Tilt for the most part has been mitigated by most AR Piston systems incorporating pads at the back end of the bolt carrier to help reduce the effects of carrier tilt. Some will experience no signs of carrier tilt, while others may see minimal to serious signs of carrier tilt.

We have always explained to customers that you will see minimal signs of carrier tilt with our Addax piston uppers, which means that you will see some anodizing rub, where the pads from the carrier are rubbing the buffer tube and making two smooth spots. (See pic. below for an example, but effects from carrier tilt will vary from rifle to rifle depending on various factors such as out of spec. buffer tubes).








Q) Why do you not recommend shooting low cost (cheap) .223 ammunition for your AR Piston Uppers like Wolf, Tula, Russian / Eastern European .223, or cheap commercial .223, or reloads?


A) Piston Driven AR's operate differently from the Standard Direct Gas AR15.

Piston Driven AR's have more moving parts, and mass, therefore require a higher and sustainable degree of gas pressure to cycle the piston system properly.

Low quality / cheap ammunition, and some commercial .223 ammunition in many cases (not all) are loaded with lower quality, slowing burning gun powders that do not produce the required and sustainable gas pressure to fully cycle a piston system reliably.

A standard Direct Gas AR only has the bolt carrier group as it's primary moving part, and this means that there is less mass and weight to operate the standard AR, and therefore can operate more reliably in many cases with ammo such as Wolf, Tula, Whitebox commercial, reloads etc.

We always recommend shooting good quality and reliable ammunition such as Federal XM193, M855 5.56, and PMC Bronze .223. It might cost you a few cents more per round to shoot the better quality ammunition, but it is worth it.

Would you run cheap quality gas in your car or truck just to save yourself a few cents per gallon, knowing your car or truck might not end up running right with the cheap quality gas? The same question applies to firearms too. Would you run cheap quality ammunition knowing it might cause issues with your firearm to function properly?



Q) What weight buffer do you recommend I use for my Addax Piston Upper for normal shooting?

A) Carbines we recommend the standard mil-spec for normal shooting. You can also try to use the H1 buffer with ammunition like XM193 or M855, but overall performance will depend on the quality of the ammunition you are using. If the ammo does not provide the necessary pressure to run the system with a H1 buffer, then revert back to a standard weight buffer.

Mid-Length we recommend the standard weight mil-spec carbine buffer for normal shooting. You can also try to use the H1 buffer with ammunition like XM193 or M855, but overall performance will depend on the quality of the ammunition you are using. If the ammo does not provide the necessary pressure to run the system with a H1 buffer, then revert back to a standard weight buffer.