Were all IBM WheelWriter keyboards buckling spring??

[sharktastica]

I have yet to encounter a non-buckling springs Wheelwriter, but that doesn't mean they non-B/S couldn't exist. Quiet Touch was available on Model Ms since the early '90s, but if your Wheelwriter indeed had rubber domes, it wouldn't be a simple difference as "less clicky" - you'd be able to tell the polarising difference instantly.

Another theory is that it could be Soft Touch (greased buckling springs), but this wasn't available on standard Model Ms until 1994 at the earliest and IBM advertised the inclusion of such as a selling point on the keyboard itself. In fact, the inclusion of either Q/T and S/T would surely be a prominently displayed since a quiet typewriter would definitely have appealed to someone. They could have even revived the Quietwriter name for those (although to clarify (and IIRC), Quietwriters were just Wheelwriters with quieter printing).

[zrrion]

Some Ms don't have rubber mats in the barrel assembly and are a lot clickier as a result.

[Darkshado]

Broken rivets with less tension in the assembly could alter feel and make a buckling spring board feel less clicky and less sharply tactile.

[kmnov2017]

How much a spring has been used also changes the "clicky" feel of a board....

[zzxx53]

Agree that broken rivets is likely cause.