my personal experience with the Magtech 240gr flatnose .44MAG is it doesn't have enough oomph to reliably cycle the Desert Eagle. it was almost 100% successful extraction, ejection from chamber, but slide didn't come back far enough to strip a round off the mag, slide went into battery on an empty chamber, click, no bang.
I was kind of bummed, I had bought a whole case of the Magtech, had to let it go at a loss just to offload it.
also had the same problem with Fiocchi 44 Mag, SJHP, 44D500, and HPR 44Mag 240gr TMJ, and also the aluminum-cased Blazer 240gr JHP. ammo is good for doing a lot of malfunction clearing drills, though, just about every round.
this is with a brand new Desert Eagle. I'm thinking the recoil springs are maybe not broken in enough, don't have enough mileage on them, to soften them up.
sofar, my 44Mag go-to ammo for my DE is American Eagle 240gr, 100% reliable, like a swiss watch.
YMMV.