IF you have a quick attach/detach system, will a flash hider or muzzle brake affect the flash hiding capability of the can?

I’ve read some posts where manufacturers say the flash hider helps, others have said the the brakes help.

Does it really make any notable difference?

Since the muzzle device is inside the can and not in open air, I'd say use a brake to help the suppressor work more effectively. Then use a suppressor that has effective flash suppression features at the end cap.

Flash suppressors are designed to work in open air. Put it inside a can and it's not in the environment it was designed for and may not mitigate flash effectively, if at all. A well designed brake will push the gas out to the sides. That can help a suppressor work more effectively, as well as protect the blast baffle (so at least you get some benefit out of it).

The only time I'd use a flash suppressor muzzle device is if I was intending to use the rifle without a suppressor a large percentage of the time.

Looking at patent drawings for some low backpressure (or flow through, as Hux/OSS trademarked) silencers in which blast chamber bleed off can bypass the main baffles, they might be more susceptible to unintended consequences of changing muzzle devices because a brake may increase the amount of “gas” that bypasses the main baffle stack. Or, inversely, a flash hider might decrease the bypass. This is probably why Hux’s “flash hider” is actually a brake designed to look like a flash hider design from the side. You’ll notice that their website avoids showing it from the front. This isn’t to knock Hux; obviously they feel that their design is better when paired as intended. The reverse-compatibility concerns their engineers have to deal with are different from the reverse-compatibility concerns that Surefire, Geissele, or Silencerco engineers have to deal with.

For traditional cans, a brake might reduce the amount of gas that can flow straight down a short and oversized bore without interacting with the baffles as much. Like my Rex .458 K can on a 5.56 gun, for example.

@Green0, that 20% formula…do you think that applies to sound as well, or would you apply a significantly different factor to your expectations in that area? 20% of an AEM5’s reflex chamber length would be like .4”. If reflex chambers are that inefficient at sound reduction, that would explain why they’re not more popular.

As always, thanks for the great info, Green0

Obviously I’m no expert. But I say yes, it does affect sound in my experience. I’ve played around with mounts on the cans I have and they all sound a tad better DT, also have a bit less gas DT.

Just my experience.

Muzzle device will absolutely effect flash when suppressed. I don't remember the exact combination I used but some micro muzzle brake + plan B on an Omega 9k (on a 300blk) gave me massive fireballs that went away completely when using the direct thread adapter

Sample size of 1 but confirms your question

Even 6.8” is a little longer than many 5.56 cans today, and that .400” extra credit for the reflex chamber is around 6% more, if it follows that formula for sound. The extra initial chamber volume does seem to make it pretty drama-free in backpressure for such a quiet can. I’m sure the vented baffles helped as well. All in all, a timeless can.

Are muzzle brakes still being considered as a sacrificial blast baffle or does that really  matter anymore?