Mushrooming buffer

[Hoot]

Do piston kits come with an adjustable gas valve? Sounds like you're a candidate for one if they do, or I'd guess too heavy a buffer or dirty tube. Heavy buffer wants to stay at rest until a greater force is acted upon it, greater force peens plastic before buffer starts rearward movement into spring. Lastly, your idea of a stronger spring, but then you worry about battering the plastic, not to mention the extension as all of that force comes forward and bangs home. Usually striping the round has a slowing before impact effect.

Hoot