Yes, it can be legal to make a silencer. For everything Form-1, from silencer designs that are easily made, to filing forms with the BATF, to 3D modeling. Remember, you must have an approved BATF Form-1 to make a silencer. All NFA laws apply.
One way to avoid or minimize the FRP to place the blast baffle in a very short distance in front of the muzzle. But what is the right distance for a MP5 supressor. The space in a B&T MP5 QD supressor is 14mm.
What about other supressors for the MP5 for example made from AAC or SWR?
Best regards
Tobi
One negative aspect associated with placing a baffle very close to the muzzle is that hot plasma will erode the crown quite quickly. It may not be so much of a problem with a pistol caliber can but it is very serious when dealing with rifle calibers.
