How would I make a flawless collision system for projectiles?

I have tried to look through multiple forum pages, and they all say roughly the same thing. Part:GetTouchingParts() should return all of the colliding parts. However, this is not working for me. I would say that for me it works around 10% of the time. Here is my function to check for collision:

function checkCollision(part) -- new
   local connection = part.Touched:Connect(function() end)
   local results = part:GetTouchingParts()
   connection:Disconnect()
   return results
end

I am using connection to get around the problem of having a part which has CanCollide set to false, and trying to get the collision of that part.

And here is where I use the function (used when a spell is fired, until there are no more spells in the workspace).

game.Workspace.Spells.Slopigus.ChildAdded:Connect(function()
    local damage
    spells_ignis = game.Workspace.Spells.Ignis:GetChildren()

    while #spells_ignis > 0 do
        wait(0.15)
        for i,v in pairs(spells_ignis) do
            local collisionCheck = checkCollision(v)
            if #collisionCheck > 0 then
                for x,y in pairs(collisionCheck) do
                    for m=1,#playerParts,1 do
                        if y.Name == playerParts[m] then
                            local characterOfCollision = y.Parent
                            local nameOfCollision = characterOfCollision.Name -- Could be used for scoreboard updates
                            -- Deal appropriate damage to player
                            characterOfCollision.Humanoid:TakeDamage(damage) -- Damage is defined inside of the "Ignis" spell object
                            break
                        end
                    end
                end
                print("Collision")
                v:Destroy()
            else
                game.ReplicatedStorage.Debug.Recieve:FireAllClients()
            end
        end
    end
end)

I am not opposed to completely re-doing my script, but I would need to know what I am doing wrong, and what I should be doing.

All help is appreciated.