(3 images) Larus fuscus fuscus 3cy HT-101.379, July 11 2003, Tampere, Finland (61.33N 24.59E).

Larus fuscus fuscus in 2cy often returns with completely replaced primaries and secondaries. In 3cy, fuscus more often shows a clear division between fresh inner primaries and older outer primaries, the inner primaries often showing neat white tips and the outer primaries often second generation-like with rounded tips and paler bleached brown. The arrested moult in the primaries is often reflected in the secondaries and (to a less extend) in the tail-feathers as well. The older tail-feathers (often R5 is older) still show a broad dark sub-terminal band.
3cy fuscus often have some black markings on the bill, which is otherwise much adult-like, with a clear red gonydeal spot. The colour of the naked parts are adult-like as well. 
The scapulars in 3cy are often completely adult-like, lacking internal patterns; plain blackish grey with a mahogany hue on the older feathers. Most wing-coverts and tertials are adult-like blackish grey as well, but often 3cy birds show some very bleached pale brown wing-coverts, normally in the greater covert bar and in the upper rows of the lesser coverts. These bleached wing-coverts accentuate the jumpy sequence in the last wing-covert moult cycles, as there is often no clear pattern in location of these bleached feathers. Head and body feathers normally are snow-white by July.

HT-101.379 was ringed  in Finland, now in 3cy. This 3cy fuscus probably has all primaries of one generation, replaced on the wintering grounds. The small white crescents are worn away, but the sub-terminal black is obvious on P4, together with the medial white line, suggesting the primaries are 3d generation. This is supported by P10, which shows a small mirror.
Note the relatively fresh outer secondaries in the bottom image, showing a grey base and large white tip, the common pattern in 3rd generation secondaries. Most rectrices appear all white. Note the adult-like bare part coloration, lacking dark markings on the bill and clear yellow iris. However, note the immature retained bleached wing-coverts.