The 100 mm M87 anti-tank gun TOPAZ is essentially the locally-built 122 mm D-30J towed howitzer (which in turn is based on the Russian 122 mm D-30) fitted with the ordnance of the Russian 100 mm anti-tank gun T-12 (2A19M). As far as it is known the 100 mm M87 anti-tank gun has yet to enter production or service. It was marketed some years ago, but a recent list issued by Yugoimport did not list this weapon as being currently on offer.

Optical equipment installed on the 100 mm M87 anti-tank gun TOPAZ includes passive day/night sight ON 100-M78, panoramic sight P-M78, range-finder D100-M78 and collimator K-M78. The fire-control system has a laser range-finder with a range from 200 to 9,995 m. Ballistic data for four types of ammunition can be inserted. The fire-control system provides an automatic sighting mark in the field of view and takes into account the type of ammunition being used, meteorological conditions, charge temperature, target speed and deviation of the muzzle velocity of the projectile.

Compared with other eastern 100 mm anti-tank guns, for example the Russian T-12, the 100 mm M87 anti-tank gun is a much more flexible system and has a higher hit probability against stationary and moving targets. The fact that it can be rapidly traversed through 360° is a major tactical advantage when compared to the baseline T-12 anti-tank gun.

The main advantages of this system have been summarised by the manufacturer as follows:

The weapon fires all types of 100 mm T-12 ammunition and has identical ballistics

The use of the D-30J three trailed carriage enables the weapon to be quickly traversed through 360° to enable it to engage moving targets and its low silhouette gives it increased battlefield survivability

It can be quickly taken into and out of action and has good mobility over rough terrain. Time into action is 150 seconds and time out of action is 180 seconds

As the gunner's seat is mounted on the upper carriage, tracking of moving targets is simplified

The auxiliary wheels fitted to the trails enable easy deployment and rapid positioning for combat

An advanced opto-electronic day/night fire-control system that incorporates a laser range-finder enables targets to be engaged under both day and night conditions with a high first round hit probability. The fire-control system takes 75 seconds to install on the weapon and 50 seconds to be removed

The installation of brakes and lights enable it to be deployed on public roads

This was declared under the CFE Treaty by Bosnia-Herzegovina. This has the ordnance of the T-12 anti-tank gun from Russia but has a different carriage without wheels as it is used in the static defence role.

This is a Serbia and Montenegrin weapon and is a D-30 carriage fitted with a 100 mm T-12 barrel.