70% Isopropyl Alcohol, Viable for Inner Barrel Cleaning?

Can also try pointing a flashlight into the magwell and peeping down the barrel (clear the gun, unplug the battery). Modern guns using LiPos etc usually have enough overspin that the nozzle doesn't block the light and you can pretty easily see if there's anything in there that needs to get cleaned. Otherwise yeah, have to pull the barrel assembly.

One note, I set my hop to near zero when cleaning - you want to clean the mound, but you don't want it hanging so low you ram the cleaning rod into it. Another note, make sure the cloth you use as a swab/patch doesn't leave lint behind. I like using those individually packed glasses cleaning wipes as the cheap ones are mostly IPA and you can tuck a few into your range bag without fear if spilling anything. Also useful for cleaning your goggles!

This is what I do to get a perfect shine...

I take a cleaning rod, either one from a real gun or one that comes with stock guns, and thread a piece of paper towel through the eye on the end. Then I put some silver polish on the paper towel scrap and jam it into the barrel, you want it to be pretty tight. Then put the other end of the cleaning rod into the chuck of an electric drill, and pull the trigger. Forty-five seconds of the drill on high speed should yield a perfectly shiny result.

Then all you have to do is force a clean paper towel scrap down the barrel till the paper towel comes out without any black residue.

I wouldn't look to see how shiny it is, you might hurt your eyes.

MAKE SURE TO REMOVE THE INNER BARREL FROM THE HOP-UP UNIT AND TAKE OFF THE BUCKING OR YOU WILL GET POLISH ON YOUR BUCKING, WHICH IS NO BUENO.

Cleaning the barrel with alcohol is fine to do without taking the barrel assembly apart, because rubbing alcohol won't hurt the bucking.