Glock 26
Ruger 10/22
Mossberg 500
M1 Garand
AR-15 lower with multiple uppers (5.56, 6.8mm, .458 SOCOM)
Nobody said anything about limiting each gun to 1 barrel.
I have avoided getting back into a multi-caliber collection for just this reason: too many different boxes of ammo to sort through. Also allows me to focus on plenty of ammo for what I have. I try to combine function as in an AR-10 type rifle for both long range and battle useage. Shotgun is unique of course.
I love guns, but buying another collection is hard to justify once retired.....
I like your thinking. Add 500 Beowulf to the list.
Don’t forget the .50 cal upper for the AR since you’re on a roll.