SEATTLE — A 65-year-old Spokane man has pleaded guilty to five charges involving illegal weapons he stockpiled in a suburban rental storage unit. Ronald L. Struve faces up to 10 years in prison and a $250,000 fine at sentencing June 5 in U.S. District Court in Seattle, where he pleaded guilty Thursday. Prosecutors say Struve rented a storage unit in Bellevue where he kept 37 machine guns, silencers, 54 grenades and plastic explosives, among other items. The arsenal was discovered when rent wasn’t paid and the unit’s contents were auctioned last November. More machine guns were found in a Spokane storage locker. It was unclear why Struve had the weapons. His lawyer said at a January hearing that Struve was “a loner-type person with some unusual political ideas,” and may have been keeping them for Armageddon.