Ah yes, the 740 Jam-O-Matic, a classic. My brother has one, and it hasn't been fired in probably close to three decades because it can't empty a magazine without jamming. It was inherited, and he has other preferred rifles so he never bothered to have it repaired. A repair on these rifles is only a temporary fix, and the jamming problem with re-appear in short order.
Do a search for Remington 740/742 problems and you will have some good reading.
The “fix” to these guns was figured out, long ago, by people who shoot far more than five boxes of ammunition in a lifetime. The chambers have to be kept clean. If you get one that has the rusted chamber, you have an option. You simply convert them to pump action. Ahlman’s has been doing it for decades. They have a few tips for tightening up the groups, as well.
https://www.ahlmans.com/remington-742-pump-conversion.htmlAll that said, I’d buy a different rifle, if I was into that kinda’ thing. The little Ruger .44 magnum I bought my Dad when he complained about the weight of his 742 hasn’t caused any trouble, but, I don't use it, either. Dad, a Garand Marine, through and through, wouldn’t use anything but a semi-automatic.
I have different notions.
Best,
Ted
