Frequently Asked Questions
Dolos and Prometheus
What handguards are compatible?
Click here for a list of compatible aftermarket handguards. We also have our own handguards that can be seen here.
Can I use the handguard I already have?
If your handguard is not on our list of compatible aftermarket handguards then you will not be able to use it with your Dolos (the list is updated as new compatible handguards are found). Our Prometheus kits come with one of our handguards and is typically less expensive than purchasing a Dolos and handguard separately.
How do I line up the rail on my handguard to my upper receiver?
What calibers can I use with the Dolos?
Can I use the Dolos with a billet upper?
The Dolos was designed based on mil-spec tech drawings of upper receivers. Since most billet uppers have external dimensions larger than mil-spec, the tabs on the back of the tri-lug assembly, or the receiver, would need to be modified to fit. It is possible to install the system with the tabs removed.
What gas system lengths work with the Dolos?
Pistol, carbine, mid-length, and rifle length gas tubes are all compatible. You are not limited to a specific gas length; however, direct impingement 45ACP uppers require the gas block to be placed too close to the upper to be compatible with the Dolos.
Can I use a piston gas system with the Dolos?
Short answer: no. We have found that the height of the gas block with many piston systems does not allow enough clearance for a handguard to be installed.
Will my barrel work with the Dolos?
If the diameter of the barrel is 1.000 inches or less, yes.
Can I use the Dolos on a Ruger Precision Rifle?
No. The barrel threads into the upper on this firearm and is not compatible with the Dolos.
What parts do I need to add a second barrel to my Dolos equipped upper?
You will need a Dolos standard lock collar and a handguard. We have barrel kits available which include one of our handguards, or check out the list of compatible handguards from other manufacturers on our support page.
Can I use the Dolos with a blowback pistol caliber?
Yes, you can. Since there isn't a gas block or tube to retain the lock collar, we recommend using our Barrel Stop-Pistol Caliber specifically for blowback builds to provide an index point and limit the collar movement when it's not attached to your upper.
When do I need to replace my lock pawl?
Several factors play into the effective life of a lock pawl. Ultimately, if you begin noticing the lock doesn't hold as well as it used to then it may be time to replace it. To replace the lock pawl, just remove the nut on the bottom of the tri-lug assembly, then the two screws from the plate. The lock pawl will slide out with the spring, and replacement lock pawls can be purchased from our retailers, which include a new spring. Insert the new lock pawl, replace the plate and screws, apply a small drop of medium threadlocker (Loctite 242 or similar), replace the plate and nut. Stop tightening the nut when the slightest resistance is met.
Can I use the Dolos with an A2 front sight post?
Yes, you can. If you are using a carbine length gas system the Prometheus SC or Prometheus MC will fit behind the post. The installation instructions will change just slightly where you will need to install your handguard onto the lock collar prior to reinstalling the gas tube and sight post.
What if I rotate my lock collar all the way and the barrel still isn't tight?
If you've made sure there is no more rotation available by pulling down on the release and attemping to rotate the lock collar further, you may need to add barrel shims between the barrel extension and lock collar.
Kentri Short Buffer
What do the profiles mean?
We have one tube profile that is specific to SB Tactical (Sig Brace) pistol braces (SKU: KTRSB), and one that is tailored to the Shockwave Blade (SKU: KTRSH). The SB profile is 1.203" and tapers up to a larger diameter to allow the soft rubber to slide on more easily and still secure the brace. The Shockwave is 1.240" and has a shoulder that stops the brace roughly an inch from the rear of the receiver.
What is the diameter of the tubes?
The SB profile is 1.203" and tapers up to a larger diameter to secure the brace. The Shockwave is 1.240" and has a shoulder that stops the brace roughly an inch from the receiver.
Is the Kentri compatible with the Law Tactical AR Folding Stock Adapter?
No. Since our buffer system replaces the standard buffer and buffer spring, and omits the buffer retaining pin, it would not function properly with the Law folder.
Can I use the Kentri with the SB Tactical PDW (SBPDW)?
No. The SBPDW uses a proprietary pistol buffer tube to retain their collapsing mechanism so the Kentri cannot be used in its place.
Does the Kentri work with 9mm and other pistol caliber ARs?
Yes, but your bolt carrier will need to be open-ended like a standard M4/M16 bolt carrier (no pinned weight) since our buffer system inserts into the open end of bolt carrier.
Can I use the SBA3 on a Kentri?
No, the SBA3 uses a proprietary buffer tube and the Kentri cannot be used in its place.
Why can't I lock the bolt to the rear right after installing?
The springs are not pre-stressed to increase the duty cycle. Over time the springs will wear in and allow the bolt to be locked to the rear (typically 60 rounds or so).