I will be sighting in the irons on my new 6920 this weekend. I found about 150 rounds of 55gr .223 in my cabinet. The duty ammo is 60 grain TAP. For a 50 yard zero, will the 55gr get me close enough that I won't be tearing through my TAP to finish it off? Or should I buy 62gr ammo to "put it paper?"

I think the 55gr will get you well within the ballpark.

You might not be able to tell much difference at all, and practically speaking, unless you are planning a prairie dog hunt, the difference won't matter.

at that close of a range I have to agree,most anything will work.
I have had a a/r from the seventy's and have found the 55 grain Nosler ballistic tips to run the best groups at 100 yards on the colt.

Great. Thanks everyone, you just saved me money