On my initial request for a McMillan stock with the Mini inlet, I was told there would be a $500 custom inlet charge. I sat on my hands for quite awhile after that, and then Boyds started doing the Mini inlet, and several chassis manufacturers entered the market with chassis made for the Mini. Manners was going to work up an inlet for the Mini; I sold Tom one of my early 6.5 Grendel bbl'd actions so he'd have something to model the inlet on. After SHOT that year (2016 or 2017, don't recall now), I quizzed them about it, since Tom had told me he'd try to have a stock at SHOT that year, but didn't. Whomever I spoke to told me that they'd backed-off the project, and that was that. However, when next I called McMillan, they told me they'd had quite a few requests for the Mini inlet, and that if I'd send them a bbl'd action, they'd forgo the custom charge. So, I sent them a 222 bbl'd action, and in due time, received a stock in Sako Varmint pattern that fit very well, and worked fine with the factory plastic bottom 'metal'. However, that stock wasn't at all comfortable in prone - at least not for me - so I called to ask if they'd do a Game Scout for me, which they agreed to do. I sold the Sako pattern stock to an online friend, and then sat back to await the completion of the Game Scout - and waited, and waited. It took several phone calls before they tracked down the almost completed stock & finally got it completed. The process took just over a year, for whatever series of reasons, I'm not sure. But it's a great stock - fits me much better in prone, and they got the action & bottom metal depths just right - at least for the 222 bbl'd action I'd sent them.
Seems Howa's plastic mags vary somewhat from one to the next, and once you get the action & bottom metal depth just right for the magazine you're using, it won't necessarily be correct for the next magazine you try to use. On top of that, the magazines are what I consider grossly over-priced, and at least right now, are not available anywhere. If Tom Manners ran into this issue while he was doing the work-up for the Mini inlet, it's no wonder he backed away from the project. I haven't called McMillan's since getting the Game Scout I have, but have heard from one or two other guys who claim they won't do stocks for the Mini now. Could be they ran into the same issue, or there could be something else going on. The Boyds stocks I've used (three of them altogether) have worked fairly well in this respect. But recently, I switched stocks between the 22 Grendel & 20 Tactical, and found that the 22 Grendel won't feed while it's in the ProVarmint stock I had the 20 Tactical in - the bolt over-rides cartridges, and won't pick one up unless I push up on the bottom of the mag while running the bolt. So...the way it looks to me, unless & until someone comes out with new & improved magazines for the Mini, shooters are going to continue to have this issue. It's a shame, really, since the Mini is such a fine little action. Mine are all quite accurate, and the action is just about perfect for the Grendel cartridge and for the wildcats based on the Grendel. It also makes a dandy 223, and can be put together to be pretty light to make a great walking varmint rifle, much like the little Sako Vixen I've always admired so much. I've talked with a very talented CNC programmer/operator who came out with his own aluminum bottom metal for the Mini, and he mentioned setting up to make aluminum mag latches that are over-length to work with magazines that don't sit high enough to feed well with the OEM plastic latch. But until Howa (or whomever is making the Mini mags) tightens up the tolerances & makes mags with consistent dimensions, a longer mag latch still won't work with some magazines. Time will tell what becomes of the little Mini action - I sure hope someone steps up and either fixes the issues that factory mags have, or makes a line of quality replacement magazines.