As we have well discussed in the "Myth busting 22LR no dud, why dud" thread, priming compound moving away from rim of loose bulk packs could heavily depend on how rough shipping and handling boxes experienced during transport (These pictures show absence of priming compound at rims of Thunderbolts) -
https://www.thehighroad.org/index.p...r-no-dud-why-dud-thread.893062/#post-12017971
And as expressed on my list of 20 different 22LR ammo tested (to include multiple lots), mostly boxed rounds produced greater accuracy than loose bulk packs possibly indicating shipping/transport damage could also affect muzzle velocity variance -
https://www.thehighroad.org/index.php?threads/federal-automatch-accuracy.904533/#post-12270603
Surprise to many, most of ammunition purchased within 6 months of testing produced 100% reliable primer ignition (with the exception of Winchester M22), including Thunderbolt and Auto Match. Only time when new 10/22 and T/CR22 produced any feeding/primer ignition issue was when they got dirty with 1000+ rounds and as long as they were kept clean and properly lubed, reliability of primer ignition returned to now approaching 10,000 rounds.
So if you experience squib rounds or rounds that do not ignite, take apart the round and see if there is priming compound at the rim. If there is any missing priming compound, it may have moved away from rim from rough shipping/transport.