I have tried SDKHook_Touch, yes. I got CollisionHook working, but it is exactly the same as using SDKHook in this case. The model is custom and it does support physics. I have also tried prop_physics (and override) but its the same.
If you want to check out the model, here it is:
https://files.catbox.moe/rx61p6.zip
Here are some pics too.
https://i.imgur.com/BTzp6HW.png
https://i.imgur.com/jGTFIJt.png
And here is an example, if I shoot through the corners, it still registers as getting hit. Its like its using the bbox instead of vphysics.
https://i.imgur.com/9ZwbOIx.png