Call Check Mate Industries and ask for Joe DeBello. They're back-ordered right now because of the panic, but they make full-tapered GI Hardball magazines. Pop the extra 2 bucks for the heavy duty spring.
They're available in blue or stainless.
Check Mate made the last government contract magazines toward the end of the Vietnam involvement up until around 1978. They were the last ones that the government contracted for.
If your front porch collapses and kills more than three dogs...You just might be a redneck