silencer question

[rvb]

I was putting some rounds through my 9mm AR this weekend. After the first couple of rounds it got even quieter (common), but then after a few rounds it got louder again, then quieter, and so on ever 5-7 rounds. Other people noticed it too, and asked about it.

Using an AAC "Phantom" silencer (aluminum, non-boosted, sealed, thread-on). It is a "wet" can, but I've never shot it wet, only "dry."

The load was my production load, 147gr zero jhp over 3.4gr titegroup, 905 fps.

I'm wondering if I need to back the load off, if perhaps not all of the powder is getting burned in the barrel (5-inch barrel!), and if after a few rounds enough un-burned powder builds up in the can causing it to burn off, maybe that's the reason?

< 1k rounds through the silencer, but never cleaned. could that be it?

anyone with a similar experience?

Thanks,

-rvb

[notasccrmom]

That's a pretty common phenomenon for a suppressor and even certain flash hiders. I'd consider that normal behavior and nothing to be worried about. It is caused by a combination of unburnt powder and gasses being reignited. It's likely that shooting it wet will help that a bit. It should also quiet it down a noticeable amount.