Custom TF2 v_ and w_models not showing up in-game

Short version: I made a custom TF2 stock Scattergun model, and I'm trying to get it to work in-game. I'm modifying the v_model for the Scattergun (models/weapons/v_models/v_scattergun.mdl), and it works when I use HLMV, but it doesn't work in TF2.

More info: I placed it under my tf/custom folder, as tf/custom/newmodels/models/weapons/v_models/v_scattergun.mdl. However, when I load it in TF2, the model is the same as the default Scattergun.

I thought maybe it was the Scattergun that had a problem, so I chose the Bat (another v_model), but that didn't work either. I also thought maybe the models were unused (since most of the weapons are c_models), so I made a w_model version of the Scattergun, but it still didn't work, and the world model was still the same. I even tested it on my own server with sv_pure set to 0, but all I saw was my default Bat and Scattergun.

I went back and checked my files to make sure the model was compiling properly, and it was. I even tried deleting any extra unused files I had in the model's folder, but nothing changed.

What's going on? I know I'm placing the models in the correct location, since I made a flamethrower and it works fine in-game. HLMV also shows the model properly, it's just TF2 that doesn't show the model.

Is there something I'm doing wrong, or do the v_ and w_ models no longer work?