This is for airsoft only! (if you put it on a real gun it would probably melt and it might not fit either)

Here is another one of my M4 style muzzle guard with only 4 holes instead of 8 so that the part is stronger because my dog broke the one with 8 holes...

here is the link to the other one incase you like the look over this one... idk
https://www.thingiverse.com/thing:4712932
That one also has some picture so you can get the basic idea.

Also I think the '.STLPRT' is only editable in solidworks...

Creality

Ender 3 Pro

No

Yes

tree supports.
print with the part you would thread on the bottom.
I don't really know, your printer may be different, your filament might be different... I've only been doing this for 2 months