Okay, buddy. Attack is the Player vs. Environment stat. The higher the attack, the more damage the gun does, and it also lets you hit higher level targets. This will also factor in during the Iron Banner, where all stats are factored in. Impact is the base damage the gun does at the optimal distance from said target. The higher the impact, the more damage the gun will do over other guns in that class (i.e. an Auto Rifle with low impact does much less damage than an Auto Rifle with mid impact rating). Range effects how far the bullet can go and still do the optimum amount of damage. The further out you are of that optimal range, the less damage you will do. From testing this, the guns go in this order of longest to shortest ranged on average: Sniper Rifle - Scout Rifle - Hand Cannon - Pulse Rifle - Auto Rifle - Heavy Machine Gun - Fusion Rifle - Shotgun. Rockets aren't counted in from what I saw. They have no Range stat, and, rather, have Velocity, which sets how fast the projectile will move. I hope this helps anyone and everyone who was confused. Any more questions? Just ask.

In the regular crucible PVP impact is basically how much damage you deal based off of that information you look at the other stats and you can tell how the gun is going to play out then you just need to tested in the game to see how you like the kick. Now when it comes to PBE or the iron banner they attack of the weapon actually does matter because it's no longer balanced to be the same number as your opponent. Same goes for your defense of rating as opposed to your classes actual armor agility and recovery when you're in the regular crucible you just want to look at those stats not your defensive pts

The range thing is there because damage drops off the farther you are from the target. As forte other stats, im in the dark as well