I worked on many a Jennings .22 trying to get them to work reliably with standard high velocity "promotional" ammo, failed on every one. The only load they would consistently cycle was Stingers. Finally concluded the recoil spring rate/slide weight was off a bit. If you weakened the recoil spring to get enough slide velocity for reliable ejection the return stroke was so weak the next round would often fail to feed. Full power recoil spring was so strong and the slide so heavy that only high pressure ammo could overcome it. Turns out most people buy a $40 .22 expecting to be able to shoot the cheap 99 cent box of ammo through it, not the $5 stuff. Go figure.
My brother had a Bryco, .380 IIRC. Cheap potmetal slide was worn away on the breechface (unknown round count) and was in general bad condition after just a few years. Plastic grips were brittle, chunks broken off the corners.
My Dad bought an RG .22 single action back in the late 70's/early 80's that wasn't too bad. The trigger spring broke after a few hundred rounds but it was easliy replaced. LR and Mag cylinders, plastic grips and a potmetal frame. Other than finish wear off it was in pretty good shape when he sold it 15 years or so later.
OTOH, got an RG double action .22 sitting in the shop right now with a broken grip frame on the frontstrap. The stress of the mainspring pushing down on it snapped it in two, looks like a early 70's vintage. I am told by metal guys that some cheap alloys actually "evaporate" one of the metals over the years, weakening the remaining metal. Similar problem is found in chromed car emblems on classic rides, real easy to snap them after 20+ years of the alloy degrading.