I thought I would explore this question more in-depth, and discuss a more clear answer. I personally believe the Light Machine Gun is the best gun to run with in Major Mayhem, but there are other weapons in the Major’s arsenal that can be argued as being the best weapon.
When writing the Major Mayhem High Score Guide the other day, I tested each weapon individually in the final level, and my best results were with the Light Machine Gun (I still haven’t earned three stars yet). My worst score came from the Chicken Cannon, which I found surprising because that gun racked up my score in Arcade mode. The issue I have with the Chicken Cannon is it is limited to one shot before a reload, making it difficult to deflect the presidents homing missiles. Furthermore, it did not provide damage to the combo when destroying missiles. Other problems I have with the Chicken Cannon include: unable to shoot through walls and slow attack rate, preventing high damage combos.
I concluded that the Chicken Cannon is not the best weapon, despite its insane cost.
The next weapon on the list was the Auto Launcher. Unlike the Chicken Cannon, the Auto Launcher provides fast attack speed with area damage. It is easy to bloat the multiplier with over kills and double kills. In addition, the Auto Launcher also provides a ten to the damage combo for every kill. I also did not find my combo to disappear due to slow attack speed and low amount of bullets. There was still a problem, however.
The Auto Launcher suffers from having a small clip size. What it could not do was boost my multiplier by providing chain kills and combo kills. Well, it still can, just not as efficiently as the Light Machine Gun, I found.
I played with the Auto Sniper Rifle next, figuring accuracy and a faster attack rate will be the winning combination of stats. With the Auto Sniper, quick kills and chain kills are easily grabbed, and the added ability to shoot through walls means the combo will not disappear when enemies take cover. Its accuracy makes the deflection of bullets, head shots, and hat hits easy. Though, the Automatic Sniper has a small clip size, and small damage compared to the explosive weapons.
The advantage the Light Machine Gun has over the Automatic Sniper, Chicken Cannon, and Automatic Launcher is an enormous clip size. Reloading is rare with the Light Machine Gun.
As any top tier weapon, the Light Machine Gun can shoot through walls, which is important if planning on achieving high scores. The Light Machine Gun doesn’t provide the best damage, but due to its clip size and fast attack speed, you can spray at least ten, but as high as thirty damage to add to your combo before the enemy disappears. In fact, you never have to lift a ring off the screen. Keep spraying and watch the multiplier sky rocket with chain kills, head shots, combo kills, hat hits, power shots, ultra shots… Therefor, I believe the Light Machine Gun is the best weapon in Major Mayhem,
Just don’t lift your finger when using it.