I built a nice little lightweight 6 RAT on a CZ527 carbine that was originally in 7.62x39 several years ago. Pulled the 7.62 bbl & replaced it with a Krieger #3 sporter contour 1-8tw that I finished at 24" - looks a little over-long in the carbine stock with its short forearm, but it's a decent shooter that's easy to carry and shoulders very nicely every time. Never have been able to get the magazine to feed with 100% reliability, but I can live with it after tweaking the mag's feedlips a bit. Mag's too short to hold rounds with any of the 105gr bullets I've tried, and without a SLED, I can't single load them anyway - which is one of the big reasons I bought several of the Howa bbl'd actions when they came on the market. First one I built was another 6 RAT, this time with a Bartlein light palma contour 1-8tw bbl, also finished at 24". I was finally able to get McMillan to do the inlet for these little actions after sending them a spare one I had in 222 Rem., and their inlet has worked really well with the cheesy plastic Howa mags in DIP aluminum DBM.
I've not called McM for another stock for any of the other three Mini builds I've done, but IIRC, someone else here or over on the Hide tried to order one, and was told they didn't do the inlet for the Mini action. Only thing I can tell you is that I wasn't happy with the 1st stock McM did for me, only because it wasn't comfortable in prone. Other than that, it worked great, with no feed issues. I sold that stock to a member here or over on the 6.5 Grendel forums, and ordered a McM Game Scout stock to replace it. I don't know what happened, but it took over a year to get that stock. Talked to a few different people at McM over the phone several times, and finally one of them told me they didn't know where the stock was, so he went looking for it. Eventually, I got a very nice Game Scout stock and the 222 Mini bbl'd action I'd sent them back, and have been very pleased with it. If the reason for the long delay was due to difficulties in getting the inlet to work, perhaps they have decided it's not worth the hassle to continue to do the Mini inlet. I have a good friend at B&C in Dodge City who did inlet modeling & moulds for their M40 & Sporter style stocks for the Howa Mini, and it's been a PITA to get them to work with Howa's plastic magazines. I think the problem is that there's a lot more variation in these magazines than any of us expected to see with today's production methods. The number of complaints about these mags over on the 6.5 Grendel forums outweigh the few shooters who've had good results with them by quite a margin. Since LSI & Howa would have to be collectively deaf, dumb, and blind not to be aware of these issues, I'm going to assume that they're either not going to try to address the problems, or (hopefully) are working on replacement mags. I'm a big fan of the Howa Mini action, and would really like to see someone come out with better magazines. Believe that's all it would take to make these little rifles quite a bit more popular.