"not uncommon practice" is correct and usable in written English.
You can use it when talking about something that is not particularly unusual or extraordinary. For example, "Having a weekly staff meeting is not an uncommon practice in most businesses."
It's possible that the F.B.I. leaked the story to Whitten, hoping to flush out the thief, a not uncommon practice.
In the short term, then, Greece would need to limit the outflow of foreign capital, an aggressive but not uncommon practice.
Finally there is the combination of various graphic methods (etching and drypoint) in a single print, a difficult though not uncommon practice suggesting that it is inappropriate to think of the graphic arts as separate processes.
The Chinese government does not censor the dispatches of foreign correspondents, but the authorities can express disapproval of a writer's work by withholding visa renewals — a not uncommon practice.
Ananiah first comes to notice in a marriage document dated Aug. 9, 449 by the Aramaic calendar, that legalized his union with Tamut, an Egyptian woman whose father had sold her to Meshullam, a not uncommon practice in payment of debts.
However, there is evidence that he was actually convicted on charges of fraud - a not uncommon practice in Soviet times.
At the time, retouching and altering images for clarity's sake were not uncommon practices; The A.P. and The Times no longer permit such changes to photographic images.
Though not an uncommon practice during the primary season, it certainly doesn't bode well for the New York senator.
All of the above are unintentional mistakes, but there exists a not uncommon company practice of deliberately misspelling words.
A gel-concentration dependent solution permittivity model is proposed for the first time, which is capable of fitting more accurately the experimental data in the literature than previous models, especially when gel concentration reaches ca. 3 wt%, which is not uncommon in practice.
The suction pressure was -400 mmHg, which is more than is recommended in some guidelines, but is not uncommon clinical practice in Scandinavia.
