From Christianity at the Crossroads:

Copying of Christian books

We have already discussed above that many Christian scribes were probably private multifunctional scribes in the service of well-to-do Christians. However, this should not be taken as evidence that all Christian scribal activity occurred in an isolated and disconnected fashion. On the contrary, the evidence above from the Shepherd and Polycarp suggests that second-century churches must have had substantial scribal resources at their disposal. While we do not have evidence that there were established ‘scriptoria’ in the second century, Scott Charlesworth has argued that the uniform features of many second-century manuscripts of the Gospels–features that include semi-literary scribal hands and reader’s aids–suggest that they were ‘produced in controlled settings, i.e., in small copy centers’. Such centres would have provided more control, uniformity and consistency in the copying task–especially in regard to the books of the New Testament.

And

If in fact manuscripts were copied in these copy centres in the second century, Charlesworth argues that these centres would probably have maintained ‘master copies’ of New Testament books from which scribes could make additional copies. KThese master copies would probably have also been the very copies that were publicly displayed and read aloud in corporate worship. Such master copies would have served to reduce the number of textual variations in the copying process by virtue of the fact that the scribes would always return to the same exemplar rather than copying from other copies of that exemplar. A recent study by Craig Evans has suggested that it was not unusual for ancient papyri to be in use (and thus copied) for two centuries or more. Thus, these master copies could have exhibited a stabilizing influence on the text of the New Testament for generations.