FX Panther magazine issues

New to pcps with magazines and this FX HPC bewilders me as I have never used one in my life.
bought used and found 2 magazines in the case.
one metal and other polymer. Both same size but one is thinner. It seems the clear part top part of one magazine is thicker than the others. I assume it’s for larger longer pellets and slugs, maybe???

My First experience with pcp mags… so the larger one fits perfectly over barrel and in the breech. it does not fall out. HOWEVER, the other one because it’s thinner just goes over the barrel andis smaller in the breech. I do notice when the probe is in or against the mag its held ok???

Then because I wanted to have lower scope I bought an FX mini mag part# 22029. The description in the website says it fits:
DRS/Panthera/Dynamic/King but when I try it on my Panthera its thin. Again it seems that the top part of mag is thinner version. It does not fill the breech area.

Am I loading it incorrectly??? There is nothing in the instructions that talk about different size mags. Can I still use these smaller ones???
Is there adapter I can put In the breech or mag??Is there another clear top part that is taller???

I really want to use the mini mag for scope height
but it looks like the only mag I have that is proper is the polymer large stock mag that fits perfectly in the breech. Can someone explain or know anything about my mag issue.im sorry for asking such a question. I cant even find a video on YouTube about it also.
 
If I understand your post correctly, you bought an FX Panthera pcp and a spare FX DRS mini magazine. While they are very similar they are not the same, nor interchangeable. To be more specific: the magazine body itself is the same size but the cover is thicker for the Panthera/King/Dynamic line to accommodate longer slugs. The DRS, Dreamline, Wildcat, Maverick and Crown use a thinner cover plate. If you buy the 'standard' size magazine, you will get both cover plates. FX at this point in time does not make the thicker covers for the DRS mini magazine, but you can find aftermarket mini magazines for the Panthera.