My nephew in Colorado has a super clean Savage 340 in .30-30 caliber that jams almost all the time when feeding from the removeable magazine. I took it apart, and nothing changed with the stock removed. I looked on the internet quite a while, and the only thing I found was possibly a magazine replacement from Brownells. Apparently it cured some rifles, and didn't cure others.
The design of the rifle makes perfect cartridge location necessary, since the chamber end of the barrel is tapered to a sharp edge (the o.d. gets larger going forward). There is no feed ramp, so the bullet must be pointed dead center at the chamber or it hangs on the sharp edge. Apparently, that was an economical way to create relief for the extractor(s) when the bolt is closing.
Before we make the $40 gamble for a new magazine, do any of you have experience with this one?