MARUZEN - NBB P99 Magazine help

[summosteve]

Hi all, over the years ive had the NBB P99 and now im losing mags at high rate and can't seem to repair them, (blown seals) so what ever oring's i buy! none of them seem to be the right size and never works out,  is there anyone out there who could shed some light my way please to the correct ones

plus ive bought the multi size packs from ebay and amazon and still not the right size

many thank!