Per Nabob's warning, the rims on the PS-Nh and the PS-T-Cv are designed to pretty much prevent being chambered in your average flare pistol. I never tried to chamber one but suspect it will not allow closure of the action.

I do have a previously mentioned BRNO RV85 "riot" gun, but it's NIB and I don't want to waste a round and dirty it all up. And flares are VERY dirty, and corrosive. I use an old/cheap/previously abused Polish pistol for shooting the regular flares and then dose it down with REMOIL when finished. Rust starts forming almost immediately.
As to Bellifortis' comments, I agree, very expensive. Long ago and far far away, one could get a box of 10 Czech flares for $20-30. Parachute flares were
$45/10 !!!!!! Made for expensive fireworks but I did acquire them as they were available.
Got a few of those left, but used only on special occasions, or to light a bonfire.
Sadly, it appears the Czech flares are no longer imported. Everyone that has them listed have shown "SOLD OUT" for years now. The German ones were the latest import but they, too, are drying up. And @$8/pop, not worth it. Regular fireworks are much less expensive.
And lastly, as for collecting, they are not long lived. Have a few that are doing this:

That right there sucks.