Shooting the VZ52 with really old (1952) surplus ammo w/ hang fire

My trip to the range with my new VZ52 rifle I bought. The store I bought it from had some surplus ammo that came in with the rifle. I might be converting this to 7.62x39. 7.62x45 ammo is expensive and unreliable. In total, I loaded 20 rounds and only six fired. The first round fired had a pretty noticeable hang fire. You can hear the hammer drop then a micro second later it fired. Not too sure if it's the ammo or the firing pin. My buddies say it makes good contact on the primer but I am not sure since they seem very shallow on some rounds.
Update since this video:
I did get the conversion kit to swap this to 7.62x39.

[@billwaller2698]

Old ammo. The ammo was like that 35 yrs ago. There is no good commercial ammor for that gun and never was. Convert it to 7.62x39 and then you can shoot it

[@williejohnson1732]

I'm am interested in this rifle, did u find out what cause the hang fire?

[@DrSnackCake5]

It’s most likely the old ammo. I’ve asked a lot of peers to see if the firing pin made good contact on the primer and they all said yes. I’m going to covert the rifle to 7.62x39.

[@williejohnson1732]

@@DrSnackCake5 I'm sorry u have to convert it.

[@DrSnackCake5]

@@williejohnson1732 there is some ammo out there for it, all surplus old stuff. Nobody makes modern ammo for it. S&B doesn’t find it profitable to manufacture ammo anymore. It’s expensive too. I bought 30 rounds of the ammo that doesn’t work for 50 bucks. I bought a ~50 conversion kit. This rifle was an impulse buy. Had heard about it on multiple UA-cam channels to pick on up if anyone had it.

[@jmscdy]

noice

[@CrackedSam]

Can I have a graphics card lol

[@7.62problems2]

uhh get a new firing pin