Mountain Howitzer made from light alloys.
+ Gives mountain troops serious punch
+ supplements AS-1912 on other fronts even if it is lighter than a proper howitzer
+ gives experience in light alloys for future use in aviation
This isn't the greatest idea, at least not for the Mountains. First of all, getting a mountain howitzer might not be possible. The smallest artillery we managed to get there is the Light Mortar. Even the AC18 is too big.
Second, I think I've figured out what's important for each terrain. In the trenches, artillery is the most important factor. In the Jungle, CQC is the most important factor. In the Mountains, marksmanship is the most important factor. Neither side gets an advantage in trenches. Moskurg gets an advantage in the Jungle due to being better at CQC and in hot weather. Arstotzka gets an advantage in the Mountains due to being better at long-range shooting and cold weather (though Moskurg has never seemed inconvenienced by the cold).
If we want to do well in the Mountains, mobility and long-range combat is what we should focus on. Our Light Mortar being very good at both mobility and long-range combat is what allowed it to be so useful in the Mountains. It's also why our Nosin and our SAR are useful.The SMG isn't useful due to not being suited to long-range combat and artillery won't be useful due to its issues with mobility (and also it's impossible to field them.) If we got a decent motorbike, that
might've given our SMGs enough mobility to counter-act their poor performance at long range, but a light machine gun would be much more useful, being portable but capable of long-range combat. In most battle reports, the Brumby - Moskurg's light machine gun - is stated as the reason why they're able to hold the line.
So yeah, no matter how light we make the howitzer it's not going to be lighter than the autocannon, and we are unable to field it despite being light enough for our men to carry by hand. If we want to win in the Mountains, we'll have to go with snipers, LMGs, or aircraft to disrupt their logistics.
Glory to Arstotzka.