How old is your Colt 9mm carbine? The Colt SP1 series used standard 0.154” fire control pins. Starting with the Sporter line, Colt used 0.169” diameter fire control pins. That continued during the Nation AWB and beyond. As I recall, it wasn’t until Colt lost their Government M4 contract to FN that Colt reverted back to using standard 0.154” fire control pins.
So unless you purchased your Colt 9mm carbine in the last 10 years, that lower probably has to larger diameter fire control pins. You might be able to use the contour of the 9mm hammer as a guide to modify your current hammer in the HK AR trigger frame. Just a thought.
Scott
ETA, that it is the extractor spring, not the ejector spring that can be damaged by a misfeed hyperextending the extractor spring. Once the extractor spring has been bent, bending it back will only last a couple of mags, if you are lucky. Mark your mags. If one causes misdeeds, take it out of use and possibly use a reliable mag as a guide to modify the bad mag back to reliable.
I have always wondered why HK never fixed this problem until the 23E. But they never went back and fixed the extractor spring problem with the rest of the roller locked bolts. HK recommends a deep cleaning at 1,000 rounds of use including removing the extractor, cleaning the bottom side and the extractor features where the extractor sits. Also it is easy to damage the extractor spring while removing it. HK recommends replacing the extractor spring at the end of the deep cleaning of the bolt.
Scott