Lately, I’ve been curious as to how different flash hider designs manage to reduce flash. When compared to an open barrel, some designs seem to employ magic or voodoo to make flash all but disappear.

In short, what makes a particular design more effective than another? Do effective designs allow for removing unburned powder from the equation? What are the physics that cause one design to show less flash than another? I’m looking for a scientific explanation of the HOW of it, not a “they just work that’s why they’re called flash hiders” answer.

A quick web search of "how do flash hiders work" pulls a number of explanations. Basically the FH mixes cooler ambient air with the hot muzzle gasses, and then disburses the gas mixture.

Currently, many of the most effective FHs seem to be based on a 3-prong design. A web search for "FH comparison" or "FH test" shows camera comparisons of many designs on the market.

As to why company A's design with a .41" gap between prongs works slightly better or worse than company B's design with a .39" gap between prongs, I doubt such engineering test studies are publicly available.

quote:

Originally posted by fritz:
Currently, many of the most effective FHs seem to be based on a 3-prong design.

When I was researching the question myself a few years ago, that’s what the demonstration videos showed. I ended up with a long three-prong AAC flash hider because I was more interested in flash suppression than other factors. My SIG 300 Blackout MCX came with a 3-prong FH, and Thunder Beast offers a similar design for use with their suppressor system (for flash suppression when the sound suppressor is removed).

It’s interesting to me as well that the earliest commonly-issued M16 rifles in Vietnam had the three-prong FH (I have a picture of myself holding one). I know that the FH was changed to the “cage” design because of complaints that the open-ended version tended to catch on vegetation when moving through the jungle, but evidently the first experiments must have demonstrated its flash suppression effectiveness. I have, however, seen many ARs with the A2 style FH fired in the dark, and it also works very well.

Three prongs, yes.

AAC Blackout non-mount rules

YHM Phantom flash hiders are very effective as well.

This has been out for a while, but still very relevant: AR-15 Flash Hider Shootout.