I shoot IPSC, not IDPA, so take my comments for what they may be worth.
The 17 round South African mags aren't beneficial for IDPA, because of the 10 round limit.
The HP Practical has a barrel weight, doesn't it? If so, I don't think that it would be legal for IDPA.
"Those who live by the sword are probably pretty f***ing good at it."
"Instructions for a successful gunfight: Front Sight, Press Trigger, repeat
as necessary." - B. Braxton