some weapons like the MP5 does not appear only sound is heard

Black Mesa Archive In-game Issues
#1

How can fix this? i have not the HD pack the workshop mod

#2

I can fix this thnks

Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.