I have a 177 cal air rifle that belonged to a good friend who passed away.  I'm trying to get it to run so I can sell it for his widow.  The other parts/issues I can deal with, but it must have at least a dozen pellets lodged in the bore starting about an inch back of the muzzle.

I've tried Kroil and a brass rod....no go.  About the only thing I can think of right now is to heat the barrel with a propane torch and melt the pellets...they're likely near pure lead...and then scrub/clean.

Has anyone done this with stuck bullets with any success?

The big question is why the pellets did not make it out of the barrel.

Maybe a 2 inch screw smaller than the bore.  Thread into the pellets and pull out?

Well, the FWB 300 I have is 1971 vintage and the seals are shot, so I suspect there wasn't enough oomph, and someone just kept trying.  The obstruction is about 5" long so it would take a 1/8 in. dia. screw of at least 6", and then assuming each pellet would come out individually...don't think that's in the cards.

How about a steel rod ( or coat hanger even) heat it red hot and " scrub " the pellets out with it?

Mercury is your answer.
It will dissolve the lead, and allow it to be easily wiped out. Any physical attempt to remove the pellets will likely introduce bore damage, no matter how careful you are, and that rifle's role in life is to be stupidly accurate.
Yeah, yeah, mercury's toxic and dangerous and will cause you to become psychotic and develop palsy and your hair and teeth will fall out and global warming will melt all the icebergs and we'll all die if you use it, blah, blah, blah. It won't take much to partially fill that tiny bore, so it's not like you're creating a superfund site.

Mercury was the go-to "back in the day" to remove lead from .22lr rifles.

What a great country!
Mercury available from Amazon

I had a 1/8" brass rod, so I sharpened the end at an angle and went in from the breech end at low speed with an electric drill.  Went in about 3" through some waxy-looking/feeling stuff, so I tried it from the muzzle end.... didn't get anything.  Didn't figure the brass would damage the bore, but now I'm stumped.  I may try filling the bore from the breech end with acetone and see if that dissolves anything.  Barring any success at that, I'll get some mercury and fill the bore from the muzzle end to see if it'll dissolve the pellet.  I can see metal from the breech end, and it feels soft, so I'm presuming it's a lead pellet, but the wax/stuff???

This is turning into a real adventure!

Further update.  I decided to try heat.  Got several dribbles of black gooey "stuff" and at least three pellets out.  Letting the barrel cool and we'll see if a rod will go through.

More update.... more heat and got at least 9 pellets out.  Scrubbed the bore and it finally smoothed out and I can't see or feel any damage.

I'm having a Coldsmoke scottish ale to celebrate!

If you ant to try and drill out something stuck in a barrel you really need an actual gun drill.

They have lubricant sent down a passage in the middle of the bit, and a groove on the OD
that acts as a swarf channel to remove the removed material.

The cutting head is mostly a flat with a very small step to make a cutting edge for the material to be removed.
While steel is used when boring barrels, a brass rod with some hardening on the cutting wend would make short work of lead pellets.

They are still a bit of a PITA to setup and use though.
It often takes a decent amount of oil pressure to force the swarf back up the length of the drill when it is in the barrel.

And while all gun drilling is a PITA as .177 type drill is all the worse.

I have seen brass and stainless tubing that has an od of <.177. You could heat the end red hot force it into the front pellet.  Let it cool, shouldn’t take long, and try to pull the pellets one by one. Red hot brass tube should have very low risk of damaging the barrel.

That or you could file teeth on the brass tube like a hole saw and try drilling them out one at a time.

I don’t know the value of your particular barrel, but I would be tempted to just do the redneck thing and hammer a brass cleaning rod through it. If it doesn’t budge, get a bigger hammer.

A 'dead blow' hammer delivers more energy without the 'bounce' of a regular hammer.