Did anyone consider that the threatening messages may be coming from someone other than shooters? There are organizations trying to disrupt everything that has to do with guns including ammo. They don't operate in the open and little is known about them.
A few come to mind. A UN organization in OKC that was pushing hard for open borders and restricted gun rights. They did have, until a few years ago, their minutes on the Web but got smart and took them down. There was a Chapter in Tulsa also. There were and probably still are Chapter's in all major cities.
The Peace House in Bethany OK that stands with every extreme movement that comes along. Not lovers of shooters.
The ACLU is no friend in general of the gun industry or owners. They have in a very few instances sided with us.
These are just a few examples. Check around your area.

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Mighty 90's,Trying 4 a 100!