They didn't pick December 21st, they did the inverse in a way. The people who built it didn't use a calendar with December as a month if they had any sort of calendar at all.

What they did was use their knowledge of how daylight changes seasonally each year, which is something they could observe, to ensure that the sun would illuminate a chamber specifically during the Winter Solstice, which happens to be December 21st on our calendar.

It's also (in fact mostly) because having the engine only use a portion of its maximum potential, so going around sixty when it could do over a hundred, is good for long-term reliability.

Nah, the aquarium is a great way to relax when you're downtown. You're missing out if you only go once or twice and you're doing others a disservice by not mentioning it imo.

I love this. Thanks for posting OP.

If someone is in melee range with you and you have rifles, the smart thing to do is push/throw/grapple them or retreat as necessary so you or a buddy can shoot them.

A bayonet on the end of your gun's muzzle makes it longer and heavier which are both a disadvantage in close quarters. Given the first point, it's a sacrifice for no real benefit.

I dont have them immediately on hand and I don't care enough to dig them up for you.

Not according to the records of both the allied and axis soldiers who were there.

TLDR compared to the M1 rifles and carbines the US already possesed the STG-44 was significantly heavier and less reliable. It's major X factor of possessing automatic fire was essentially useless as automatic fire is not useful for most rifleman in general and the STG-44 in particular was not well designed for sustained automatic fire.

Indeed and it was primarily used in semi-auto by German troops. The concept of an assault rifle as we know it today was not really achieved in technical design or tactical use until to introduction of the AK47.

In that case the soviets were looking for a replacement for their SMGs rather than intentionally introducing a new type of weapon.

As the Wikipedia article mentions this was about preventing unattended fires rather than policing peoples sleep schedule.