Neil Winston tested these chokes a few years back, in 2016. They were neither better, nor worse, than the similarly dimensioned choke tubes he compared them against.
Here is the summary of his test:
Review and Summary
Using an article by Nick Sisley as a model, I tested two Briley Helix choke tubes, Modified and Extra Full, against two other extended chokes of the same constriction but conventional design. I shot 40 patterns and analyzed them with the program Shotgun-Insight, which is an absolutely necessary tool for this sort of task.
• Using “central thickening,” an objective numerical alternative to visual estimation of pattern “hotness,” I did not confirm Mr. Sisley’s assessment that Briley “appears to have something there.” Evaluating two tests together, I did not find any reliable difference.
• Using “75% shot diameter,” an objective numerical alternative to visual estimation of pattern width, I did not confirm Mr. Sisley’s impression that the Helix chokes produced “slightly wider” patterns. In neither of two comparisons was there any difference at all in pattern width.
CONCLUSION:
The tested Briley Helix® chokes performed well, but just the same as equally-constricted conventional choke tubes. The Helix feature had no effect at all on the patterns.
