Back in the mid 1960s I worked with a retired CID agent for the army. He told me he carried one of those. At the time that didnt sound right to me, but a few years ago I read some place that was what they were issued, or at least some were.
It should be accurate. Maybe you had incompatable ammo or something. I dont think they were made for hi speed ammo. I have a similar long barreled HDM.