I did like this.

"They earned some fame for unreliability because the bolt tended to override the rebated rim of the .425, especially when worked fast in an emergency, causing a solid jam."

And in the sentence before "that the post-WW2 W-R "Game Ranger" rifles lacked the cartridge retaining clips and the careful handfitting."

That is kind of not surprising that he found the second part over ride / jam) after the first part (lacking retaining clips).