here is a post by SmokinOkie back in 2010 hope he doesn't mind
SmokinOkie
On a Permanent vacation, seeing America by RV
posted November 18, 2010 03:25 PM
Probably the # on question I get. In class, in the forum, in emails, in person.
We've heard it for years (it's even on the turkey you buy).
Here's why. Read this list, just did a quick list of temp, time, pounds and you'll see the variations.
As I say all the time, there are too many variations in turkey size, shape, brining, smokers, methods, etc to just give a set time.
Now I did a QUICK (read that to mean I probably had a math error)
but there are rough times per # and I group them roughly
CONCLUSION? Cook on internal bird temp, not on time:
325-350 to 2 ½ to 3 hours (no weight listed)
325-360 for 2 ½ hours (17#) (8.8 min per #)
325-350 300 for 4 ¼ hours (13#) (19.2 min per #)
325 for 2 ½ to 3 hours (12#) (15 min per #)
325 for 4 hours (18#) (13.3 min per #)
325 for 6 ½ to 7 hours (21#) (20 min per #)
From 8.8 to 20 min per #
300 2 ¾ hours (17.5#) (9.1 min per #)
300 for 3 hours (15#) (12 min per #)
300 for 2 ½ hours (8# breast) (18.7 min per #)
300-335 for 4 ½ to 5 hours (no weight listed)
300 for 4 ½ hours (15# breast) (16.6 min per #)
From 9.1 to 18.7 min per #
275 for 7 ¾ hours (22#) (20.4 min per #)
275 for 3 hours (14#) (12.8 min per #)
275-280 for 3 hours (9.3#) (19.3 min per #)
275 for 2 ¾ (9# breast) (17.7 min per #)
275 for 2 ½ hours (13.72#) (10.9 min per #)
From 10.9 to 20.4 min per #
250 for 3 ½ hours (13#) (16.1 min per #)
250 for 6 hours and 220 for 3 hours (13#) (41 min per #)
250 for 3 hours and 325 for 1 ½ hours (16#) (15 min per #)
250 for 3 ½ hours (14#)250 for 3 ¾ hours (7 lb breast) (31.4 min per #)
250 for 4 hours (12.5#) (19.2 min per #)
250 for 6 hours (14½#) (24.8 min per #)
250 for 1.5 hours (11#) (8 min per #)
From 8 to 41 min per #
235 for 6 hours (8# breast) (45 min per #)
230 for 2 ¾ hours (13#) (12.3 min per #)
225-250 for 6 hours (12#) (30 min per #)
225-250 for 3.5 to 4 hours (10# bird and 6# breast) (24 min and 40 min per #)
225-275 for 3 ½ to 4 hours (no weight listed)
225 for 8-10 hrs (was partially frozen on purpose) (no weight listed)
225 for 4 hours and 350 for 1 ½ hours (21#) (15.7 min per #)
From 12.3 to 40 min per #