My Browning A-Bolt synthetic bought new 25 years ago has shown no deterioration from cleaning solvent, sweat, blood or sunlight. Ditto Ruger mini-14 synthetic about 15 years old. Both rifles used professionally.
Have seen a few rifles & shotguns with soft rubber inserts glued into the grip panels, sometimes the inserts had rotted or peeled. A Sako 75 synthetic for example.
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