There are supposedly two different die pairs for the proofs of this year but so far I can only confirm one variety from the examples that have been studied. This one variety comes with the 71 in the date very close or they look they are touching at the top depending on the die state. The upright of the last 1 in the date points directly at the tip of the curl and the date is slightly higher than center in the field, slightly closer to the bottom of the bust then to the tops of the denticles.
The one confirmed variety appears to come in at least four different reverse die rotations. It has been found properly aligned with no rotation, but most of the time it is found with the reverse rotated counterclockwise to either the 11:30 position or only slightly rotated. Then sometimes it is found rotated clockwise to about the 12:30 position. The 11:30 and 12:30 rotations are reported in the Ultimate Guide to Three Cent Nickels, 1865 to 1889, by Allan Gifford. The non-rotated and slightly counterclockwise rotated reverses have been observed on examples being offered at auction and at coin shows.
In Walter Breen’s Encyclopedia of United States and Colonial Proof Coins, 1722-1989, the listing for the 1871 Three Cents proof starts off by mentioning that the 71 touch or about touch, date high and then continues by mentioning rev. long faint line slanting down to right above center. This is the feature that immediately caught my eye on every proof 1871 that I have examined. If you look at the right numeral on the reverse there is always this long line in the field cutting diagonal through the numeral. It is a sure giveaway for this die pair.
If the other die pair does exist it supposedly has the date lower in the field, the 71 apart at the top, and the upright of the last 1 points to the left of the tip of the curl. Maybe with further searching this second die pair will be found and its diagnostics can be documented.
In the meantime, the first example we have available for study was formally in an ANACS holder without a grade but listed * GENUINE *, PROOF, CLEANED and is our inventory number 249. This coin has the reverse rotated counterclockwise to the 11:30 position which seems to be the most common position for the die pair.
This other example we have is in an ANACS PF62 holder, is inventory number 256, and has the reverse rotated on slightly clockwise, which seems to be the second most often found position. The non-rotated reverse is the next most often found reverse position and then the reverse rotated clockwise to the 12:30 position seems to be the scarcest reverse rotation.
The date position shown below from #249 is as described before, slightly higher than center in the field and the upright of the last 1 in the date points at the tip of the curl. In the proof encyclopedia the outer serif positions match those found here, the left serif of the first 1 is just right of the left edge and the right serif of the last 1 is over the right edge of the denticle below(I drew the line a little crooked). Then the other digit positions shown are the right serif of the first 1 is between the left edge and the center of the denticle. The center of the 8 points down at the right edge of the denticle below. The center of the 7 points at the center of the denticle below. The arrow added to the picture is pointing to the top of the 71 touching or almost touching.
Here is a closeup of the 71 in the date touching or almost touching at the top.
For comparison, here is the date area from #256 with the lines added to indicated the positions of each digit to the elements around it. Also the arrow points to the top of the 71 which appear to be almost touching.
In Breens proof book he continued in his description to mention that there are, extra outlines on CA only, which isnt really true because there is light outlining on some other letters in UNITED STATES OF AMERICA also. In Giffords Ultimate 3cNkl book he refers to this diagnostic as faint Class B Longacre doubling is present on all obverse letters. In my experience it is difficult to count on the outlining of the obverse letters as diagnostics for different varieties because the appearance of the outlines can be inconsistent from coin to coin depending on the die wear and strike. Below is a closeup of the CA on #249. As you can see the outlining is far from convincing because its strong on the right of the A but pretty weak around the C.
One outline that I have noticed standing out on the 1871 proofs is left of the left upright of the U shown here from #256. It may not be visible on all examples.
Next I noticed a lot of very strong horizontal die lines on the rear lower bust in front of and continuing into the curls. This picture below from #249 shows the horizontal lines well between the arrows that have been added.
A squiggly line on front of coronet extends to bottom left base of I in
LIBERTY, shown below on #249. I have noticed this same feature on other proof dates and business strikes so it may be on working hub or master die that transferred it to more than one working die in several years. Future study of this feature on more coins should help understand the origins of this line on the coronet.
Through the nostrils and the lips are vertical die lines shown below, between the arrows, from coin #249.
In front of the ear are lots of circular die lines and the lower right inside of the ear is filled with die lines. All of these lines are shown between the arrows added to this picture from #249.
At the very back of the hair and in the hair bun there are strong vertical die lines as shown below on #249. Also in the hair are lighter circular die lines nearly paralleling the curves of the hair.
Now let us look on to the reverse for some diagnostics. There is a short diagonal die line on the second highest leaf left of the bow. It extends from the edge of the bow onto that leaf. This picture is from the PF62 coin #256.
Finally what is to me the most noticeable diagnostic every time I look at an 1871 proof is a long diagonal die line that runs from between the tops of the center and right numeral down through the upper part of the right numeral out into the field to the right and over to the inner edge of the right wreath. This is mentioned in the Breen proof encyclopedia as rev. long faint line slanting down to r. above center. This line is very easy to see but was hard to photograph. Below it is first shown on #249 and then after that on #256 which has glare in the picture because of the plastic of the ANACS holder. First the diagonal reverse line on #249:
Then also shown here is the same line on the PF62 ANACS coin #256:
In conclusion, the 1871 Proof has many diagnostics to look for and comes in several reverse rotations. We also have the mysterious report of a second die with the 71 seperated at the top and the date slightly lower. If someone has one or finds one of these I would like to know about it. In the meanwhile Ill be looking for this other die and if I do find it, the details will be added to these webpages.