i don't own RTAK2. I own SP8. The sheath of SP8 fits SP5 quite well. SO here is one more option for you.Would it be possible to trade/exchange these sheaths for the better fitting RTAKll sheaths?
SP53 are with the same length of PS5, with a bigger belly. But why they share a sheath which is 1 inch longer than both of them, is beyond me. Anyway, case solved.
BTW, OKC Sales has not replied to my email as of now.