A while back someone here posted about a mag sleave that could be cut down to use the 2.0c 15 rnd mag in a 1.0c. Sorry to say I have 3 extras but the only ID is a very faint Amerigun.com but that web site seems to be just links to other sites. Search this forum for the link. The sleeves are too long so you modify them by shortening either the top or botton. Depending which you get two different results;
20180225_141827 by craig stuard, on Flickr
or
20180225_141758 by craig stuard, on Flickr
I use the second one.