This might be nothing, but when looking at the pic of the underside of your Mini, down through the magwell, I >>think<< I see some items protruding into the magwell from the sides.
Did the problem with inserting/removing the trigger guard first occur when you began using the new stock, or did you encounter the same problem with the original stock?
The trigger group looks to be in the right place and seated, but not locked into place. Take a look inside the magwell, and see if there is anything hung-up or being forced inwards. I'll bet you will find it difficult to insert a magazine--but don't force it!
Did the problem with inserting/removing the trigger guard first occur when you began using the new stock, or did you encounter the same problem with the original stock?
The trigger group looks to be in the right place and seated, but not locked into place. Take a look inside the magwell, and see if there is anything hung-up or being forced inwards. I'll bet you will find it difficult to insert a magazine--but don't force it!