NOTE: in most cases, the most effective ammunition is APDS (see HELP AMMUNITION in-game for details)
NOTE: APDS does not exist for assault cannons, making direct comparisons a bit more complicated, so they are not included here
NOTE: assumes the wielder fires only as many rounds as the recoil compensation can handle
NOTE: stats used are of the best performing weapon variant for each weapon class in the given situation
NOTE: defender has +1 TN penalty to dodge for every 3 rounds (round down)
NOTE: may require a gunsmithing workshop to replace an existing gas vent with an improved gas vent IV

The base TN to dodge is 4. Assuming no other modifiers, opponents roll to dodge against TN 6 when facing FA 6, compared to TN 5 when facing FA 5 (or BF). With SR3's dice mechanics, rolling against TN 6 averages half the number of successes compared to rolling against TN 5. Thus, an AR or SMG can be more effective than an HMG despite the lower power. On the other hand, defenders aren't permitted to dodge in surprise situations, which is what lets sniper rifles be competitive.

NOTE: the heavy gyromount uses the “about the body” equipment slot
NOTE: tripod use requires the prone position (thus no dodge dice, penalty to target you with ranged, and bonus to target you with melee)

(WIP)

Here are some example setups following the rules for layering and sets (see HELP LAYERING and HELP ARMOUR SETS in-game for details)
NOTE: while layering penalties are calculated for B and I separately, the highest rating that doesn't get its ratings halved is the piece (or combined set total) with the highest B+I (e.g. a 5/4 and a 4/5 results in a total rating of 7/6 or 6/7, NOT 7/7)
NOTE: helmet, armguards, cyber/bioware, and/or magic IGNORE layering rules, so are NOT INCLUDED in the examples below (just add whatever you have directly on top of the pieces that do follow layering rules)
NOTE: form-fitting armor DOES count in B/I rating layering, but DOES NOT count for determining penalties
NOTE: when a shield is equipped, only one-handed weapons can be used
An Armor Layering Calculator is available to help you explore these rules.