Welcome to the forum Noah. What you said about walking upright, cracked me up. I try to keep from dragging my knuckles myself.
If you are getting 2 1/2" Average groups with no scope, thats not bad, with a scope I believe we can do a little better.
Ok now lets see if we can tweek your mini a little more, so just gonna throw some stuff at ya, as I don't know what you know, you know?
1. Are your reloads you are shooting the best of many you tried? I have experimented with, many bullet types, weights, and powder types, and quantities, Grouped brass by weight to the nearest .1 grains etc. Some loads shoot twice as tight a groups, as others. Each mini is different so a good load for mine may not be for yours.
2. Have ya removed copper build up from the bore, with a good copper solvent?
3. Is your mini older, if so maby the crown is worn a little from improper cleaning?
4. When you bedded the stock, did you also bed the Stock Reinforcement to the Receiver?
5. Have ya had a trigger job? I haven't seen anyone that is very accurate with a 7 lb trigger pull.
6. As gutpile suguested, gapped, and retorqued the gas blocks
7. Are you shooting with a good scope? A scope will beat a peep.
8. Your shooting technique? using a sandbag, bipod or shooting rest? Same cheek to stock spot weld, and pressure, stock to shoulder pressure, breath control, forestock nested in same spot each shot.
The smaller gas port bushing, or shock buffer, dosen't contribute to accuracy directly, except it reduces recoil so rapid fire is faster, as it allows you to stay on the bull. The reduced recoil also is easier on a scope. The only down side is if you switch ammo with the smaller gas bushing, it may become a bolt gun, untill you adjust gas with a larger one.
Finally barrel heat, when shooting for accuracy, I let the barrel cool when I can't stand to touch it for 30 seconds.
See if any of the above helps.