The ideas I express here are my opinions and just that; but are the result of over 30 years experience with the AR platform.
Aftermarket Gas blocks are usually attached in one of two ways, via clamping or with set screws.
Set screws provide NO clamping force and rely on one or more of the tiny set screws to not only seal, but to retain the block in place. This method is the most simple and least expensive to manufacture but is also the least reliable.
Clamping provides for a superior sealing function as well as solid positioning and will withstand a blow that would skew the best of the set screw types.
Many manufacturers make aluminum gas blocks; (we did as well) some are 7075-T6 like ours but many are only 6061-T6. The first is a higher strength and more expensive alloy. Aluminum expands with heat at a rate of approx. three times that of steel. This leads to gas leakage at the gas tube, just no way around it.
Couple this to varying diameters in gas tubes and it becomes a point of failure. Gas jet erosion in the port is also evident.
Adjustable gas blocks:
Here is a bone of contention. Yes, they can work but I am not convinced they are worth the liabilities they can incur. Having asked many shooters that use them, most run them wide open. I have also seen them eroded to the point of failure due to attempting to cut down an over-gased gun.(too large of gas port in barrel) This and the frequent failures with the adjusting screw as they can come loose, they strip, they fall out or even break off.
These problems and others have convinced me to stop building them.
Our New Direction
The quest was to design and build a gas block with none of the previously inherent flaws. Our new block is made from high quality stainless steel only.
- 1) It has two #10-32 clamping screws with full size heads.
- 2) It fits under free float tubes.
- 3) It has lead-in cuts for the roll pin and gas tube to ease in assembly.
- 4) It has a very sleek profile and weighs only 730 grains.
- 5) It has a tasteful machined finish with Firebird logo laser engraved.
- 6) The gas port has a lead-in counter bore.
- 7) The gas port location for use with free float tubes shoulders on the barrel for precise alignment without handguard cup.
It is my desire to serve the shooting community with the very best components I can build.
- Jim, Firebird Precision Firearms