Please keep us informed. I wonder about the magazine differnces - is that real or fable?
The round poping out of the mag lends me to believe that there is a lip issue and / or possibly a magazine diameter issue.

The lip issue would certainly tie in with the feeding problems. Good luck - I know you dont think so , but I feel its worth it. You got one or two with issues -- I dont wnat to start up the whole thing again.

I am interested to see if the A-Square ammo is somehow different than their test ammo.

I dont know if your 458 test target would have the same info, but my BRNO doubles show the test ammo used by brand and grain of bullet. It may help you out. Did you try other types of ammo or bullets in your Lott? I agree that if they pop out that is not a good thing and the type of bullet would make no difference. For comparison sake - i remember reading on-line that someone with a CZ Lott or maybe 458????? had feeding issues in the field and took a piece of cartridge box and slipped a slice at the rear (I think) of the magazine and that little difference made it feed perfectly.

Not what you wanted to play with I know -- but just thought you may find it interesting to see.

Good Luck

If I lived in the States - i would likely offer to buy them and get them to work come hell or high water.