What Grade Of MS Is A Freshly Minted Coin For Circulation?

Could be generally anywhere from MS 60 to MS 67 in all likelihood. The average 1966 roll and UNC nickel I have encountered is about MS 63.
The 1966 is well known for weak strike and lack of detail which takes one point away.
The nickels could have been in a mint sewn bag and tossed around from one bank to another and then again to others before even making it to the counter/wrapper. Storage conditions could make some distracting discolorations and spots.
There is no way anyone can actually answer your question. You have to open the roll and look them over. Dumping them on a table will take another grade point off many of them and mishandling them could as well.
Gently open the end and let them slide out slowly onto a nice soft cloth surface and inspect them by holding them by the edges as if you were giving somebody the OK sign with your fingers.
Chances are some will be much nicer than others. I sort them at this point in rows. I would put the very best in a 2x2 holder and make sure you wipe any dust and paper fragments off the plastic inside. Don't breath or sneeze on your coins.
This exercise will answer the question for you.

The other alternative is that you leave them in the roll and figure you probably have an average of 40 MS 63 nickels. But without seeing you will not know.

5 Step 1966 Jefferson nickels are quite scarce and bring a premium price. If I had a nice roll, I would look for nice step counts as well. 1966 SMS nickels are more easily found with steps and are a completely different coin altogether.

hey wheezy
What you wrote makes perfect sense regardless of the origin of the coins, and very helpful.
Thanks for the effort !!

Hello Gord, your makin' my mouth water thinking about the slim possibilities of that roll. What I'd give to be the first to search it!
I'd don't know what it is about the 1966, Canada 5c piece, but I've been looking in vain trying to locate an I.C.C.S., MS-65 example and have not found one as of yet. I've had no problem acquiring all other Elizabethan nickels in an I.C.C.S., MS-65, but the '66, forget it! However Gord, if you do come across a pristine example and have it slabbed by I.C.C.S. as an MS-65, just contact me and NAME YOUR PRICE, I'll be glad to accommodate.
Perhaps like previous Members have mentioned that this particular year has a weak strike seems to make sense.
As a matter of fact, I don't even recall ever seeing one pop up on E-bay. Is there anyone out there reading this that may have an example? The 2009 I.C.C.S. Population Report states that there are 4 known in their slabs, so why havn't I come across one.

Glenn

Hey 1cent, everything's for sale in this world, & for the right price, even YOU could be!............................LOL.

Glenn