Profile, Abilities and Weaknesses description is from The Transformers: More Than Meets the Eye, published by Dreamwave Comics.

BIO: Like fellow Pretender Cloudburst, Gunrunner feels more confident when secure within his shell but for different reasons.
Gunrunner was once in command of a strike force that had penetrated Decepticon front lines and was discovered. He and his team, all close friends, came under withering gunfire.  Gunrunner tried to keep everyone calm, swearing that he would see to it that all of them made it back in one piece. Gunrunner was the only Pretender in the group, and it was the extra armor of his vehicle shell that narrowly saved him from destruction.  His friends were not so lucky. When Gunrunner limped back to the Autobot forward command station as the only survivor of his team, he returned a bitter and changed 'bot. Although still bold when in his shell, the experience left its mark by making him totally insecure when battling in just his robot or jet mode. He retains his title of squadron commander but refuses to take command over any team on a permanent basis, afraid of making friends. He no longer tries to reassure his temporary troops that everything will work out in a battle; saying that made him a liar once, and he won't let that happen again. 

WEAPONS/ABILITIES: Subject is a Pretender whose outer shell is an all-terrain ground vehicle with hydraulic-powered armored wheels. It's armed with dual electro-static cannon turrets. The vehicle's targeting system makes the cannons accurate at a range of up to 60 miles. The shell can also launch two armor-piercing missiles that carry an explosive plasma charge; their range is 100 miles. Thermal generators in the shell's armor allow it to burn through obstacles as dense as solid rock walls. Inner robot transforms into a jet with a maximum speed of Mach 5; the jet is also armed with the electro-static cannons, but their effective range is halved without the targeting computers of the shell. In robot mode, Subject carries a plasma machine gun and can also launch the missiles, although the effective range in this mode is only 2 miles.

WEAKNESSES: Subject's reluctance to fight outside of his shell lowers his effectiveness and can even endanger his troops. 

Bibliography of significant appearances:  Gunrunner made zero appearances in the G1 Transformers fiction.  He did make an ultra brief cameo appearance in a few IDW comics, Spotlight: Optimus Prime and possibly Stormbringer (see image, just below).  Each so insignificant, they're not hardly worth mentioning!  Is this a Don Figueroa rendition of Gunrunner?  It's pretty ambiguous, lets roll with this for now until he's featured elsewhere more prominently.