No No No! does no one listen? There are so many arms that are better than the m4 the HK416 the G-36 etc etc
The helmet looks like most ballistic Kevlar types so will be more than sufficient! It covers the soldiers head well and does not look bulky, so will not interfere with his head in a prone position.
How do you know? Have you fired a wide selection of weapons and made that conclusion? or are you just guessing? Oh and since you believe weapons don't make a difference I will meet you with a gun and you can have a stick. Since weapons don't make a difference you will win right? Use your brains if you have any!