My guess is that the 122mm APCBC was supposed to be introduced for the T-10 but with the later more powerfull 122mm cannon, they changed the designation to BR-472, since that was the only AP round the more powerfull 122mm fired. So the shell was probably only called BR-471D for a short time and the stocks of old BR-471 and BR-471Bs were instead issued to the IS-2s, IS-3s and IS-4s that were kept in reserve.
The higher the velocity, the more you get out of APC shells. Being able to pierce thick armor plates like on turrets, while flat shells have very poor performance under such conditions.
So it makes sense that 100mm and 85mm high velocity guns would change to APC rounds, and that the 122mm APC was mainly developed for the high velocity 122mm M-62 cannon.
The photo of the shell posted is NOT the BR-472, look it has a single driving band while the BR-472 has double driving bands, like the Pzgr.39/42 and Pzgr. 39/43 and other shells designed to be fired from a high pressure/high velocity guns.
Like I said, probably it was intended for the T-10 with the D-25TS but after the T-10 received the more powerful cannon they changed the round to be fired from the new cannon, creating BR-472.
They probably didn’t bother producing the APC shell for the D-25T and thus the BR-471D only existed for a short period.
At first, I was baffled when I saw you talking about the “D-25TS” gun in this context, but then I realized there existed two soviet guns with this designation (in Cyrillic “Д-25ТС”)
Edit: actually I’m wrong and @KillaKiwi is right. There was always only one “Д-25ТС” gun.
I see. Guess this confirms that this shell was put in service.
On the topic of it’s performance IRL:
I have taken the data for the german 128mm Pzgr. from this graph here as a reference to estimate the performance that the BR-471D would’ve had:
It says the ammo for the D-25T can be used in the D-49 and the D-49 was practically the same cannon found in the T-10A, which were both modernised variants of the D-25T.
Which sounds like both T-10A and SU-122-54 would have used the BR-471D shell as well as all the ammunition that was used for the D-25T but not that the D-25T would also fire the BR-741D, even though it was/should be possible.
Obviously they would produce the ammo to be used in the T-10A and SU-122-54 but I don’t think that the ammunition would have been issued to vehicles using the D-25T that were somewhat obsolete and being replaced.
And neither T-10A/B or SU-122-54 were around for a long time.
Both the T-10M and the D-74 field cannon used the BR-472 shell as their only convential AP round.
The BR-471B shell was one of two armour-piercing shells originally available to the T-10 in 1953. The BR-471 shell of WWII vintage can skipped over even though wartime stockpiles of this obsolete shell still existed because T-10 tanks were simply not intended to use this shell, given that the TSh2-27 and TPS1 sights were only marked for BR-471B rounds.
Although the BR-471 shell was the standard armour-piercing round for IS-2 tanks during WWII, the BR-471B shell already began supplanting it in 1945, albeit too late to see combat in Europe, and it replaced the BR-471 entirely during the 1950’s. The main targets of BR-471 shells during its heyday were German tanks such as Panthers and Tigers, against which it was generally quite successful. Even Tiger II tanks could fall victim to this shell under certain circumstances. However, its performance on sloped armour plate, and its long range energy retention, were both not ideal as it was a simple sharp-tipped projectile.
