Well, depending on whether a Soviet AT Artillery Brigade is 2 x 480 man Regiments or 1 Regiment + another 500 supporting troops, of which 100 are SMG Infantry and 330 are Pioneers (who can act as Infantry in a pinch), they have less than 1000 men all up ...
According to Glantz (and other sources) your typical non-Guards unit was 40-60% understrength (in Main sectors, up to 80% understrength in secondary sectors) at any given time, that would mean far, far less than 1000 men.
In mid/late 42 most German Mechanised Divisions (10000-14000 TO&E strength) would be at least 75% strength or more.
So, regardless of how you cut it, its gonna be either
a) No infantry and only artillerists and support troops, perhaps as few as 200, probably around 500)
b) 20-60 SMG Infantry, 65-200 Pioneers + artillerists and support troops, perhaps another 100-250)
against 7500-9000 Germans
And the Germans are fully mechanised (or close enough thereto) offensively and defensively while the Russians can dig and fight, and be immobile, or hitch up and run, and get slaughtered.
Towed artillery units *by themselves* against mechanised units truly *are* speed-bumps.
They would only ever be *deliberately* deployed in conjunction with Infantry in the defense, the Infantry being needed to screen them.
In DC:CB the TO&E Strengths are ...
Soviet AT Battalion (it's not actually listed as either a Regiment or Brigade ... it probably represents a single Regiment, therefore, as Soviet "Regiments" were often of a strength that other armies would have called Battalions anyway)
25 Heavy AT
25 Light AT
which doesn't represent *either* the actual TO&E for an AT Regiment (460 men, 20 ATG, 20 ATR, 68 Trucks, 1 Car, 6 Horse Waggons) *or* an AT Brigade (16 ATG, 12 Lt ATG, 8 Medium & 4 Heavy Mortars, 187 Trucks, 16 Motorcycles, 4 Cars, 100 Infantry, 330 Pioneer)
Either its meant to represent the Battalion, and has far, far, far too many trucks *and* the "Infantry" should either be subsumed in the gun's values rather than listed separately, or the "Infantry" should be second rate, and reduced ability.
Author, Space Opera (FGU); RBB #1 (FASA); Road to Armageddon; Farm, Forge and Steam; Orbis Mundi; Displaced (PGD)