What is the reason for 'head down and away' when opening the feed cover? Various instructional videos show this step when opening an M240B, but no one explains why it's done.




I could only think of two things.




Maybe has to do with a cookoff when opening the feed cover. But if that was the case, shouldn't the operator move his whole head out of the way?




Maybe it's a spring that can eject backwards and take out an eye. But I've examine my M240B and I don't see any such spring.




I don't see or hear about 'head down and away' when opening an M60 or MG42.


















 

When firing live ammo, you have your helmet on, saves you in event of cook off. Even without helmet, protect your eyes.

Protection from a cook off.

Yep.



Lot's of people get excited when something goes wrong mid belt.  It's easy to forget to give the weapon time to cool.  If something does go wrong, you want your head protected from the fragmenting shell.  First impulse is to be watching the area of the problem when you open the feed tray, exactly what you shouldn't be doing - for your eyes sake.

So why not just move your whole head out of the way and look at the area from a diagonal vantage point?

Yes, it assumes a helmet.



Civy side, I would just give it more time to cool before opening it.

Unless you wear a helmet all the time like me

And how exactly do you plan on doing that? Separate your head from your neck, hand it to your AG and have him point you at your weapon?

You are limited by the fact that you will be proned out and holding/manipulating your weapon. You can only move your head so far. Down and away is safe since the receiver is between you and any potential explosion/KB.

i seen a guy open the top cover and fire a round.... i guess a round was still on the feed tray...
that was interesting...

Cook offs scary. Use your kevlar to protect your noggin.

How does a cook off occur in an open bolt MG?

The only time a cartridge would be in a hot chamber is the millisecond after the bolt closes/before it fires.......

The only instance I could think of would be when trying to clear a FTF after firing a long series.....

eta: from the manual......

"Clearing the Weapon

Clearing the weapon is performed by ensuring the bolt is locked to the rear and the weapon is on safe. The feed tray cover is then lifted, the remaining belt (if any) is swept out of the feed tray, the feed tray is lifted to visually inspect the rear of the barrel and the face of the bolt. Any links or brass casings are removed. The weapon is now clear. In the unlikely event that a live round is on the bolt face, it is knocked loose with a cleaning rod or another rigid object. If there is a live round lodged in the barrel, the operator must immediately decide if the barrel is hot enough that there is a chance of it cooking off. If there is, he will immediately move his face away from the opening of the weapon. He should then wait for the barrel to cool off before attempting to remove it. In many cases, attempting to remove the barrel will cause the round to detonate as soon as the barrel is unlocked from the receiver. He can also attempt to extract the round by taking the weapon off of safe, pulling the trigger and pulling back on the charging handle. This has a fair chance of causing the weapon to fire, so care should be made in ensuring that the weapon is pointed in a safe direction first."

It's possible to have a round that is stripped and pushed forward by the bolt, but the extractor fails to engage the case rim.




I've seen this happen with another guys' post sample M60 that was poorly maintained.





 


Also, it's possible to have a bad primer that fails to ignite the powder charge. Because there is no energy to cycle the action, the bolt stays forward with the round in chamber. If the barrel is hot enough, it's possible that the barrel will cook off the powder charge. Always wait a bit if there is a failure to ignite.


 

I'm studying and getting to know the M240B. Eventually, I'll make a review of the M240B versus the M60E6, with video.




The M240B is quite a gun.


Here's the current iteration of the M60, the M60E6, next to the M240B. The M60E6 feels a lot shorter than it is because of its semi-bullpup design.








The M240 is a much longer than the M60E6.  Here is a top view of the guns.









The M240B carries awkwardly, not just because of its balance, but because the ejection port on the bottom digs into your shoulder.









Here's where the 240 balances









Here's where the M60 balances









Both guns are quite awesome.




*these are NFA registered machine guns.



 

Excellent comparison. I always wondered how they stacked up as far as size, weight, shapes etc...

Nvm. Someone contacted me with a solution. Thanks for the info.

MK43,E4,E6 is awesome.