I had very little time to run by the range and test the Melonite 4566 for function. I managed to run 110 rounds through it in about 20 minutes. That included fighting with the 3 mags which came with it.
In 27 years of shooting 3rd gen 45s I have never had any magazine problems. Never. In thousands of rounds. In fact, 3rd gen 45 mags are one of the primary factors in the sterling reliability of these pistols. But this year, I have had problems with NIB CS45 mags and these three 8-round mags.
To start with none of the three supplied mags would load easily. VERY problematic trying to get rounds into them. I had Federal 230 ball, Speer Gold Dot 230 JHP, Winchester Ranger 230 JHP and Blazer Brass 230 ball.
NONE of the mags would load with the Speer Gold Dot. Get one round in and no more. Mag was frozen up. Winchester Ranger and Federal 230 ball would load into the mags, but then they would only feed the top two rounds, the slide closing on an empty chamber. Blazer would load but only feed the top round. Vexing!
Luckily I had two 8-round S&W 3rd gen 45 mags in my range bag. I loaded those up and my 4566M ate everything and functioned perfectly.

Nice trigger and VERY accurate! Like all my other 3rd gen 45s this one liked the Winchester Ranger T 230 JHP best. It put them into sub 2 inch groups at 10 yards. (Lane pulley was screwed up and only went out to 10 yards.)
I love this pistol! Well worth the wait to get it.
The three mags that camewith it will be tried againwith my CS45. Since they are the only 8-round mags I have ever come across with the CS45 like indentions at the top, perhaps they will work in the CS45 and be used as reload or range mags. If not, I will strip them for parts as the springs and followers were in excellent condition. Regards 18DAI