Do military/industrial tubes sound better than regular ones ?

Be careful buying " medical" and " instrument" grade tubes.  Especially 6922 as they were used in a lot of test equipment.   Many are not NOS , they were pulled from gear as it was phased out and replaced  by solid state.   "Pulls" as they are known.  Many of those tubes were robust and still tested as new when pulled.  Plain white boxes and weak lettering is a red flag. 

Military vacuum tubes are built to specifications that ensure resistance to failure in high vibration environments and tighter tolerances³. They are not necessarily for the military, but are manufactured to meet these requirements³⁵

^{Perhaps tighter tolerances may impact the sound, but I believe the ones labeled for the military are no different than the ones labeled for any other use, probably coming off the same line, only labeled differently.}

Well, Brent from Audio Tubes has both regular 12AU7 RCA black plates and military/industrial ones, all from 50s, not sure early or late 50s. He also calls industrial Command Series. I have regular ones installed, so I could order a set of military/industrial, burn them in for 100 hours and then compare. Return them if I hear no difference and lose 20% which would not be much, those tubes are $99 each and I would need three of them. I just don’t want to start with this and don’t want to buy more tubes right away, last week spent $450 for a matched pair of 12AX7 NOS Mullards longplates from 50s. They are excellent tubes, hard to find, so I bought a spare pair from Brent.

Russia also has their military grade tubes. The Russian Rockets Reflektor 6N23P are a popular tube still used by many especially in heaphone amps. These tubes were used by the Russian Space program back in the 70's. I still have a set in an old tube amp. I'm sure there are many others.

I've had good luck with JAN/Phillips 6922 tubes but I don't think being military is a guarantee of better sound or longer life.