All the threads on the forum requesting the date of manufacture are getting a little out of hand and thus we (the staff) have come to the conclusion that we will no longer be dating any rifles with a serial number beginning with a letter. This is because these guns aren't that old and the letter prefix itself will give you a relative idea of when the rifle was manufactured. The "dating" service is intended more for dating and documenting the older collectable guns that are no longer in production and were made prior to 1968.
No Letter Prefix or no serial number = made prior to 1968
"A" prefix started in 1968 when the 'Gun Control Act of 1968' went into effect.
"B" prefix started in 1972 and ran through the end of 1974
"C" prefix started in 1975 and ran through the end of ????
"E" prefix started in ????
"F" prefix with a serial number lower than F498821 = 1988 thru Nov. 1st, 1995
"F" prefix with a serial number higher than F498821 = Nov. 1st, 1995 through the early part of 2002
"G" prefix started in 2002 with the introduction of the AccuTrigger and round-top receiver
"H" prefix started in January of 2010
"J" prefix started in late July/early August 2013