The MP43/1 was probably developed before the MP43. It shared the large muzzle threads, constant diameter barrel behind the front sight, and rear sight base (with telescope mounting rails) with the MKb42(H). The muzzle threads and barrel size allowed the use of the MKb grenade launcher, and the rear sight rails allowed the use of the MKb scope mounting system. Both of these systems were not developed after the MKb production ceased, so existing telescope mounts and grenade launchers were used.
Elimination of the MKb features caused MP43/1 production to cease at the end of 1943 or the beginning of 1944. Production of the MP43/1 evidentally precluded production of the MP43, or overlapped it for a short time.
Small numbers of MP43/1's with MP43 features will be encountered, and are most probably the result of using up all MKb parts. Some rifles with MP43 muzzle characteristics or rear sight bases have been noted.
