I believe there are something like 4 versions of the .219 Donaldson Wasp with different positions of the shoulder and different lengths of the neck. Donaldson's last version was a long body long neck. I'm also surprised the Zipper didn't fit. Please do a chamber cast and give us the measurements so we can match it up and end the suspense. It only takes a few minutes and is very easy to do. https://www.brownells.com/search/index.htm?k=chamber+cast&ksubmit=y
https://www.midwayusa.com/product/462291/national-metallic-chamber-casting-alloy-1-2-lb