I found a way in which you can "create" the same basic free mod without spending a single resource.
· You need
a weapon that can support a muzzle mod. That is,
Supressor, Muzzle Break, Compensator or Bayonet, in regular guns. Very common weapons that support this kind of mods are, for example,
10mm Pistols or
Pipe Pistols. You'll find loads of these during the game.
Also, you can use
any legendary gun that has a muzzle attachment. I got it using the
"Deliverer" silenced 10mm pistol that you can accept as a reward during the Railroad faction mission "Tradecraft".
· Anyways, once you have one of these basic pistols (either with o without a muzzle attachment), or one legendary one, head to a
Weapons Workbench. The game is full of them, so just fast travel to any settlement. Sanctuary, for example.
· If your weapon doesn't have a muzzle attachment, create it. Bayonet has low requirements.
· Click on
"No muzzle". The game will ask you to "create" the mod at no cost. Do it. Then, put back the mod you just removed. Then, click on "No muzzle" again. The game will ask you to create it again. Repeat it 50 times.
· Here's a small video for clarification. My game is in Spanish, but it should be clear.