DG,
I have to wonder if that might just be barrel specific. I say that because sometime back I had an extra PM9 barrel that had a hood that stopped considerably short of the breech face and it functioned just fine. I don't remember what it measured now, but you could see it at a glance.
FWIW, there is a TP45 barrel, guide rod, and spring on Ebay right now for just under $100.
Regards,
Greg