2A46 is a common barrel used by T-64, T-72, T-80, T-84 and T-90 tanks and most plastic kit manufacturers offerings of this part are not very accurate.
JS models released a replacement resin gun barrel
for Tamiya T-72, which can be used with their T-72M1 turret and
with some minor modifications on all 1/35-scale models of tanks
that haves gun as their main armament. The barrel is one-piece
resin part with thin casting release lines on five of its sections
on the right side. Clean up is minimal and does not take long.
The advantages that this product offers over the others are that
it has the ring with bolts at its base and the weld lines on
the fume extractor. Other details include nicely molded thermal
jacket straps and bolt details on the fume extractor. Real 2A46
gun barrel on Finish Army T-72M1 tank was used for the reference.