Okay, the range went good, as I had hoped when I did the final backyard shoot yesterday.
Magazines-
Here's what I feel I can safely say- tight mags don't work well. Some of the plastic ones can get a bit bulged and this can hamper the action from working. I don't think that's the firearms fault. To address this I'm going to file and down and polish the 3 magwell protrusions a bit more. They are almost-but not quite- flush with the main part of the magwell.
IMI mags are pretty slim and they worked best. RRA metal mags, older MFT mags worked good too. Newer MFT mags bullged a bit and I think it's just due to the new springs bunching the cartridges up more. Cross mags were okay. The factory mags were ok.
Ammo-
Use full power handloads or full power factory loads. I use PMC and full power handloads until today. Today I also brought along some mid range handloads that are sorta generic and work in many other firearm platforms but forget about anything but full power in this gun. The mid range were hit and miss. Some would cycle the action properly, some would not. I think the recoil spring is just too beefy to use anything weaker. Using the charging handle you can feel the springs strength, it takes effort, unlike an AR or similar design.
Why was I having problems at first? I suspect it was the recoil spring breaking in and maybe getting settled . Pushing the tail up too much and plunging the bolt face down. I would suggest buyers of this rifle expect to use 50 or more rounds to break it in. You shouldn't have to do this but it is what it is.
Pick magazines that fit easily, shoot the hell out of it and it should be good to go.
If I can find another one for sale I'll buy a second but they all seem sold out right now!