(Бр-2)) was a Soviet 152.4 mm heavy gun, produced in limited numbers by the Barrikady Plant in Stalingrad in the late 1930s.

The most unusual feature of the gun was its tracked carriage, shared by a number of Soviet heavy artillery systems of the interwar period.

Work on a long range 152 mm gun for Reserve of the Main Command units started in 1929, when the Bolshevik Plant in Saint Petersburg received from the Artillery Directorate requirements specifications for such a piece.

First barrel was manufactured in April 1932; it was sent for trials even before the carriage, which had an unusual tracked construction, was ready.

Development and testing of the B-10 continued until 1935; a number of problems were revealed, including slow elevation, low rate of fire and short service life.

The Soviet Navy briefly considered adopting a derived weapon as a coastal gun, in towed or self-propelled variant, the latter based on T-28 medium tank chassis.

Only the towed variant, B-25, reached factory trials; eventually it was canceled because of shortcomings of the design and decision of the Army not to adopt the B-10.

The B-30 barrels were also used for ultimately unsuccessful experiments with pre-rifled shells and with "Ansaldo system" variable depth rifling.

While generally similar to the competing design, the Br-2 had different barrel construction (built-up vs loose liner), slightly different breechblock and featured an equilibrating mechanism.

However, it was decided to switch to free tube barrel construction in production pieces, making the gun somewhat more similar to the B-30.

The latter solution was eventually preferred and from 1938 a variant with deep rifling replaced the original barrel in production.

However, service life of the new barrel was measured using different criterion (10% drop in muzzle velocity), so actual improvement was probably much smaller.

It took until 1955 to develop a variant of the Br-2 – designated Br-2M – which had wheeled carriage and didn't require separate transportation.

The Br-2 was also used in a number of unsuccessful experiments with discarding sabot shells, intended to increase range.

The barrel was damaged during the experiments; additionally, the gun was found to have unsatisfactory ballistics and problems with loading.

In the trials report of 7 August 1938 both were referred to as unsatisfactory; the former because of bad passability and the latter because of excessive weight.

[2] As of June 1941, the RKKA possessed 37 or 38[3] pieces, of them 24 in the aforementioned heavy artillery regiment and further four in two independent batteries.

In Autumn 1941 the experimental piece shelled German forces from Kubinka proving ground.