If you think that it is unrealistic to make an assault rifle without a factory & its skilled workers - think again.
The gunsmiths of Pakistan make quite effective small arms with rudamentary tools & resources.
Also, how many of you guys can make a powerful enough bow to take down a deer, let alone a bear, hmm?
Ranting aside, I do think that military/civilian firearms & ammunition & stuff of the sort should be harder to craft & get hold of in general. In my opinion, in order to craft a Kalash you would need ~5-7 blueprints to study all of the parts that you might find, either separate or as whole weapon.
When you study it, it gets destroyed, since you cut it open in order to make a blueprint in order to study it. When you have blueprints of all parts of the gun, you can craft the parts & then put them together in order to have the finished product.
Another way of doing it would be that you cant ‘study’ blueprints, meaning that when you intend to craft something advanced, say a rifle, you need to have the blueprints either on your person or in close proximity in order to make the parts you need.
Meaning without any blueprints, you cant do shit. Also meaning that loosing a blueprint now costs you much more than it did before & it also gives you a use for the paper resource.