I know this is out of my area of expertise but the entire line of these rifles were really fussy when it came to feeding from magazines. It may be an over simplification but find another original magazine or two, they aren't cheap but it's probably the best solution.
I love to digress but when I was coaching an Air Force Reserve team we had a whole bunch of 513T and other 500 Line rifles. We rarely used the magazines but on those occasions when it was required about one out of three wouldn't feed properly. After a hour or so of switching them from rifle to rifle we had all but one feeding properly. The same held true for rifles like the Winchester 69a, 75, & 52.............they were fussy about magazines and once you started messing with them like bending the ears or whatever they just got worse!!!
Keep checking Ebay and the auction sites, you will find one eventually.
Jim Peterson
Charlotte, NC
scoremaster wont chamber round from mag
Re: scoremaster wont chamber round from mag
Jim Peterson