The Greek text of the Textus Receptus:
εἰς κληρονομίαν ἄφθαρτον καὶ ἀμίαντον καὶ ἀμάραντον τετηρημένην ἐν οὐρανοῖς εἰς ἡμᾶς
εἰς ἡμᾶς are basic Greek words, so how could such learned Greek scholars make such a simple error? Is there any reason for the translation of εἰς ἡμᾶς as "for you" rather than "for us," knowing that the translators of the KJV used the Textus Receptus as their source text?
Here is an image of the 1611 Authorized Version (King James Bible):
Most every critical text I have (including the NA27, the SBL GNT, UBS4, Westcott/Hort, and the Robinson/Pierpont Byzantine GNT which usually follows the TR) all say εἰς ὑμᾶς, which would support the KJV translation. Metzger and other textual commentators that I have available say nothing about a variant reading.
Stephen's 1550 TR reads εἰς ἡμᾶς, as does Elzevir's 1624 edition. However, Scrivener’s 1881 TR does not (it has εἰς ὑμᾶς). It appears that if a variant did exist, all early English translators consistently treated εἰς ὑμᾶς as if it were the preferred reading (including the translators of the KJV, Douay–Rheims Bible, Tyndale Bible, etc.), and Scrivener apparently modified his TR text in 1881 to indicate this.
This is a little beyond the scope of the question, but I wanted to add some additional information since no reliable textual variant commentary can be found. The Syriac Peshitta, an Aramaic translation of the Greek New Testament from approximately the second century, also supports the second person plural reading (εἰς ὑμᾶς), which indicates that this is a very early reading.
The 1611 KJV has "for us" in the margin, indicating a manuscript variant. In such cases the choice relates to context. A likely contextual reason "you" was preferred is that Peter is speaking to Gentiles undergoing persecution for their faith, as noted in verses 6-7. Likely he would want to assure them that the promise of an incorruptable inheritance in heaven applies to them, to encourage them to remain faithful to Christ. This follows from verse 3 where "us" refers to all Christians and their lively hope based upon the Resurrection, and Peter would want to let these Gentiles he is addressing know that they have this hope as the strength to endure the struggles of the earthly life. Thus the KJV reading is the most directly applicable one, but this doesn't mean that the accuracy of the Received Text is questionable. Rather, the two readings are really equivalent because the use of "you" recognizes the application to all believers in Christ since the persons addressed are part of one great body of believers who all have the same hope.
