I have a lot of Russian, Romy, Hungarian, etc. barrel parts that I cut off of barrels over the last hundred years or so, they are minty parts but just have dremil slits on the bottom where you can't see them. Perfect for what you are doing. Mostly AKM and AK-74 parts, let me know what you need, just doing one rifle? I've got enough for quite a few dummy rifles. What kind are you doing, BTW? I'll send you a full compliment, plus extras, if you can find a good use for it. It's cheap
I could probably send you a complete rifle kit made up of junked out or less desirable or used parts, except for the barrel and receiver. It will be a complete mix master, of course.