Thunders are dirty ... Aguila has given me three out of battery fires and I don't feel safe shooting them anymore. 555s run decent and I don't have any misfires.
During my nearly 40,000 round testing in several 10/22s and new Take Down model along with ARs with CMMG 22LR conversion bolts the past 4 years, I had inconsistent feeding and primer ignition issues that I swore off "Thunder Duds" forever. And as expected, few rounds of Federal bulk duds were accepted as "typical" for cheap bulk ammo.
Since some of my ammunition were decades old, for my 10,000 round 10/22 and T/CR22 break-in threads, I bought and shot only new lot ammunition purchased within 6 months to 1 year.
Guess what?
I experienced no misfeeds and no misfires, even from the dreaded "Thunder Duds" using 10 round magazines. And as round count increased to thousands of rounds, I found as long as I kept the firearms and magazines clean, all various 20+ brand/weight/nose profile/lot ammunition fired consistently (Only exception was Winchester M22 which consistently produced several duds out of each 500 round bulk box for all different firearms used: 10/22, T/CR22, ARs with CMMG 22LR bolt, GSG 1911).
Curious to why this could happen so I did a "myth busting" thread to realize that perhaps all boxed/loose bulk ammunition had priming compound at the rim when they left the factory and they would all fire reliably but during rough shipping and handling, some priming compound could have moved away and these voids in priming compound at the rim could be causing duds -
https://www.thehighroad.org/index.php?threads/myth-busting-22lr-no-dud-why-dud-thread.893062/
During my 650,000 round centerfire pistol shooting journey the past 30 years with countless 22LR fired (I averaged 15K/year so I guess around 500,000 rounds of 22LR), I have seen consumable parts like springs and magazine followers wear needing replacement. Many of us shoot more 22LR than other centerfire cartridges and how often do we change magazine springs or followers?
"But it used to feed reliably before ... must be the cheap crappy ammo they are making these days."
So before we are quick to blame the ammunition, we should look at firearm fouling, magazine fouling/wear, parts wear/breakage, ammunition handling/storage/age.