So I ordered a challlenger and a challlenger bullpup regulator, I received two HP SS regulators and two bullpup plenums. Part numbers are similar so I guess its a honest mistake, they told me they'd send two more and I can do what I want with the HP SS regulators, but i also got a invoice for another $69 and they never sent anything for a standard challlenger just two bullpup regulators and I put one in my standard challlenger and it seemed fine, not leaking, fired, but it was late and I put it away. Next day im ready to shoot and psi was at 2k so wtf, start degassing and must have got below set pressure and I heard it shoot to the front of the tube and there's nothing holding that end oring in place then it drops back down and I decided im never dealing with that again and don't need a regulator for hunting so im selling everything in pairs, cheap. $70 for the 2 HP SS and $50 for the pair of Challlenger standard bullpup, the used bullpup regulator is obviously missing the bottom oring that got shredded.
Update, HP SS have been sold