Many of you know these things. Kudos, but this is to inform and help those who don’t.
The maximum a projectile can go after hitting an object is 6 blocks. So if you space things out 7 blocks, you prevent projectiles of all kinds from hitting anything behind your armor until the part hit is destroyed. It works well to protect against Scorpions especially, but also machine guns/miniguns/etc if you use your “shoot through parts” against said guns.
For protecting against Scorpions, you want to use anything with ~260+ durability. This is because certain perks/co-drivers buff Scorps to hit for that much (and rarely more if using say, a Humpback. But in general, 260 is the magic number). And if the first shot destroys the part, the next pierces further into your build. Parts that are great for that include the Elbow, the Gun Mount, Gessan bumper, Train Plow, Freight Train Plow. They all require two Scorp shots to hit to destroy them, thus stopping the dual Scorp from reaching 7 blocks away.
Shoot through parts allow the bullet projectiles to go 6 blocks further, while only taking 10% of the damage themselves. Put simply, a Punisher’s base damage is 12. So a Gun Mount can stop 32 bullets (384 worth of straight damage) before it is destroyed. So to effectively use the spacing to your advantage, use shoot through parts and leave a 6 blocks gap between the front of the shoot through parts, and your weapons.
Using “Shoot through” parts diagonally (front and left, front and right) from your guns, you can prevent shooters from being able to shoot your guns whilst you aren’t looking directly at them. This is especially effective when using omni-directional movement parts (basically everything except wheels).
If you have a spider with machine guns/Reapers/Vindicators/anything really, you can get your 1v1 engagement with the enemy you are facing, while preventing other enemies who are diagonal from you from shooting your guns immediately. Often times it is the difference between 2 people ganging up on you and stripping you immediately, or you being able to engage an enemy while keeping others from hitting your guns, allowing you to strip the first before the second can hit your weapons, or simply allow you enough time to get back into cover.
Hope this helps. I can add pictures and examples later on if anyone would like.