The H&K G41 was developed for the NATO trials of the early 1980s, which were set up to look at both rifles and cartridges for NATO standardization (although they did not end up choosing a rifle). The gun is a basically an HK33 roller-delayed system set up to use standard M16 magazines and with a selection of other M16 features like a dust cover, forward assist, catty handle, and bolt holdopen/release. Two versions were made, a standard length rifle and a shorter barreled carbine with a collapsing stock. The system was not a commercial success; most potential clients opted to either buy the HK33 or the M16, rather than this sort-of hybrid.
It is worth noting that the G41 was the first H&K rifle to offer a 3-round limited burst option and the first to use the universal bullet icon selector markings, both of which have become commonplace on all their other weapons since. Thanks to H&K for giving me access to these rifles to bring to you!