Do you think the rusty dies are the answer...fully or even partially ?
Ironglow,
While rusty dies can cause problems, stuck cases being the most common. With some brass a FL sizing die just won't return the case to spec in the web area. This is not a AR specific problem. Occasionally a round sized with a conventional FL sizing die is just not going to chamber in any chamber of correct dimensions. Throw in the use of cases fired in another chamber, the odds go way up. Anyone loading for any length of time has learned this lesson. Just a minor annoyance in a hunting rifle where a reasonable person will chamber check his ammo before going afield, a real problem in a business gun. Like Lloyd, I trim, chamfer, deburr, swage, and size using SB dies. Lots of work, but essential for ammo that simply must work.
Savage