Its definatly a magwell seating issue, you said you tried tape, maybe in the wrong place or just need to try smaller peices in certain areas, in mine I have small square peices on all sides and then 2 small peices of duct tape right at the bottom of the back side, right in front of the trigger guard.. Now it feeds 100%.
You also might need a different mag catch, might not be holding them up high enough. Modify it a bit or try a different one.
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W1-5
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