I have a Phantom flash hider I plan to use on my 9mm pistol. This particular version has one "wide" section that you would normally position straight down to prevent kicking up dust when using a rifle on a bipod. 

Unfortunately, the way the threads and crush washer worked out when finger tight, the portion that is supposed to be straight down is just a little bit past that position. In order to time it straight down, I'd have to turn it almost a full turn from finger tight. Is there enough leeway in a crush washer to do this? 

Given that 9mm is thicker than 5.56, the barrel walls are thinner under the threads so I didn't want to try it without asking first.

Yes, a brand new crush washer should be able to handle about 1.25 full rotations of the muzzle device past finger tight.

Thanks!

Don't use a crush washer with a suppressor. They may cause misalignment. You need to find a shim set to use.

MAHA

Check out downrange products, they sell some timing shims in miultiple thread size.  They offer black oxide shims to keep things in the dark if that matters to ya.  I was able to time two devices with one pack.  
 
No way affiliiated, just a great product.

I assume he's just talking about the flash hider, not the suppressor mount.  But if he IS talking about a suppressor mount, absolutely do not use a crush washer...

Also make sure your flash hider has a large enough bore to clear 9mm...