The BRT CustomTune Gas Port reduces gas system flow and corrects excessive gas drive from barrels with large gas ports or used with a dedicated suppressor.
The CustomTune Gas Port is installed inside the gas block or FSB between the barrel and gas tube.
After installation, it requires no user adjustments or maintenance.
The port cannot fall out, come loose or go out of adjustment.
It is available with a variety of port sizes to meet many applications.
This items consists of 1 gas port.
Installation generally requires the use of the FSB install kit, which is available separately.
FSB ports have smaller bodies and are not compatible with many low profile gas blocks; Use HD ports instead.
Installation requires removal and re-installation of the low profile gas block or front sight base.
Installation is relatively easy and may take less than a half hour, start to finish.
Please allow 3-5 days for items to process.
5.56 10.5" CAR: .073" (Mk18)
5.56 11.5" CAR: .070"
5.56 16" CAR: .063"
5.56 16" MID: .076"
Here are a few examples. This barrel had a large gas port.
It was very overgassed, cycled too quickly and ejected brass forward.
The insertable gas port was used to bring it back down to normal.
Function is now exactly where it should be and it shoots great.
The owner then wanted to run this same upper with the suppressor.
Suppressors add even more gas drive, so the insertable gas port was swapped out with a smaller one.
With the smaller port to compensate for the suppressor, it functions just like before.