Both. The Lawgiver was designed to be a multipurpose, long range, incredible deadly firearm, capable of supporting a Judge in the deadly environments of MegaCity One. The weapon was durable, capable of being used as a bludgeon in addition to shooting people at ranges up to three miles with smart ammunition.
Because Judges tended to die in the line of duty, Lawgivers were designed to detonate if the proper biometric handprint wasn't used, to keep them from be used against other Judges.
The Lawgiver Mark I was a multifeed device capable of taking ammo from three different chambers allowing three different types of ammunition able to be selected by a dial.
The Lawgiver Mark II (in the comics) drew all of their ammo from a single chamber and each round was jacketed as needed. (Call it super-science, and leave it at that). The weapon was also capable of add-ons for a variety of grenades, stun rounds and hypodermics.
The multiple round system supported a variety of common round types including:
Standard Execution (SE): ammunition used in response to generic situations.
'Armor-Piercing (AP)': ammunition used to deal with Robots or lifeforms wearing body armor. Armor-Piercing rounds are also powerful enough to go through cover or multiple unarmored perps.
'Ricochet (R)': rubber-titanium ammunition used to shoot perps around corners and behind walls. Can be used in standoff situations to allow Judges to shoot around hostages.
Incendiary (I): partially explosive chemical rounds that ignite whatever target they hit.
'High-Explosive (HE, Hi-Ex)': these rounds can be used when a situation calls for a forced entry into an area and there isn't time to wait for heavier reinforcements.
'Heatseeker (HS)': rounds that lock on and seek targets by their body-heat. Can be used in combination with incendiary rounds.
The Grenade bullet was replaced by a larger clip-on Fragmentation grenade shell.
PSI Division Exorcists carry Exorcism rounds instead of Heat-Seekers.
In the Movies
The Lawgiver has been shown to be slightly less capable in most movie depictions where it has more than one feed chamber feeding a variety of ammunition, allowing it to run out of one type of ammo but retaining others.
At the Academy of Law, Judge Dredd (played by Sylvester Stallone) is seen demonstrating the Lawgiver, which has a clip of 25 rounds. The ammunition is referred to as "mission-variable" and "voice-programmed".
Apparently the ammunition is a generic multi-purpose slug that turns into a specialized type (High Explosive, Armor-Piercing, etc.) when it is verbally designated by the operator. The High-Explosive round was called "Grenade".
There is also a new "Signal Flare" ammunition (though it might be a different name for the Incendiary round). The anti-tampering boobytrap differed in that it gave a lethal shock rather than detonating an explosive charge.
The Lawgiver in the 2012 film Dredd resembles the MK II model. The "Hot Shot" round used in the standoff in the beginning of the movie, although carrying the nickname of the Heat Seeker round, is more of a focused pyrotechnic.
- The incendiary round proper serves as a white-phosphorous cluster-grenade. It also has a digital screen that indicates what type of rounds are to be fired (e.g. when Dredd commands "High Ex", the display says "HIGH EX", showing that "High Ex" has been selected).