Hi,

You should reset the .grad field of your weights and biais to None if you change their size to avoid any size problem when accumulating gradients.
You should rewrap your new weight into an nn.Parameter() before setting it so that it will be properly catched by things like model.parameters(). Also note that your pruning will break the previous model.parameters() so you need to do it again after the pruning.
You can monkey patch the convolution parameters directly into the instance you have (see the names here 8 for what to change) or create a brand new one and replace the other nn.Module with things like model.conv1 = my_new_module.