RWE #45: Going house to house and through the walls? That was not the first time those tactics were employed.

I have in mind the Siege of Bexar, Dec 1835.

WHO WILL GO WITH OLD BEN MILAM INTO SAN ANTONIO?

The difference between that and Achen? In 1835 the Mexicans had all the cannon.
So the decisive element were those rifles. Final score was 20 to 30 men lost on the Texan side, including Ben Milam. Mexicans lost over 400 dead and took numerous wounded.

I rather imagine that General Perfecto de Cos thought lands and grooves should be outlawed.