Gonna be straight with you - your mech's cockpit glass should be sturdy enough to stop shots from enemy hand guns.
see your mistake is thinking that a scopedog is designed to protect the inhabitant. iirc they're intentionally filled with incredibly explosive fluid in all the joints and they're about as durable as you'd expect based on that
However, since Armored Troopers have extremely thin armor, and use a highly combustible liquid in their artificial muscle, their pilots have a very low chance of survival and are commonly referred to instead as "Bottoms", the lowest of the low ("Votoms" and "Bottoms" are written and pronounced the same way in Japanese).
watched so much gundam that at first i was just like "what he just shot the camera who cares"
Want an entire show of "guy brings a gun to a mech fight"? Good news, there's Votoms spinoff Armor Hunter Mellowlink and it's cool as fuck.
I found a YouTube link in your post. Here are links to the same video on alternative frontends that protect your privacy: