JD Outfitters of OKC has several in .458 Lott listed on GB, two of which are converts from .458 Win Mag. They seem reasonably priced. He has some more MRC rifles listed in lesser calibers including .338 Win Mag.
The company's Model 1999 receiver, with its Mauser-style controlled-round-feed system of operation, laid the firm’s foundation solidly on performance, timeless function and looks to match. After closing its doors in early 2020, it appears the manufacturer is on the verge of making a comeback.
Overall I really like their design. They (he, the original designer) combined Mauser and Win 70 features. MRC also provided a somewhat scarce product to a relatively small niche market- the big, heavy, long mag action needed for a few of the “oversized” cartridges. A couple of the best features of the Win 70 are incorporated in the MRC 1999- the trigger and safety. I just wish they would have incorporated one other of the post ‘68 Win 70 improvements… the anti-bind feature, a simple but effect improvement to the basic Mauser bolt action. I suppose it could still be under Winchester’s, now FN/Herstal, copyright protection… but I don’t know?? Also could be the M1999 designer didn’t think it important- IMO, a mistake. In any case hope they make a successful come back. Competition is a good thing.