Hi, what weapon are you using, barrel length, any flash hider?  If this is ONLY happening while you're firing there may be a great big fireball in front of you and the tubes are dimming down a lot and it appears they may be shutting down completely if the flash is that bright.  Firing indoors can also have an even "brighter" effect on muzzle flash.  Power cycling is also a normal procedure if the tubes cut off for this reason.

Do you have another weapon (maybe with a better flash suppressor or can) you can shoot to see if you're having the same effect or for that matter go to an outdoor range?  With both tubes doing the same thing, I am inclined to think you may have some serious flash coming from your weapon. If not, we can always take a look at the BNVD's, but give a few other options a try first and let me know.


Vic

Hmmm, Phantom FH's should not be billowing fireballs. (Smith Vortex and the B.E. Meyers are superb as well). Do take it outdoors and see what happens along with another rifle (maybe just a .22 rimfire to see if any difference if flash is doing this).  If still persists, (you purchased it from us) give us a call and we can surely have a look-see.  Thanks Brother.

Vic