I've been loading 125TC coated bullets and other coated bullets as well. I was having the same problem. With coated bullets they recommend more flare in the case so it doesn't damage the coating during seating. I back my crimp die out to the least amount of tapered crimp and seat the bullet to the d...

Before buying my SFX, I had read that it was designed for 124GR NATO rounds. I ran about 400 124GR rounds thru for break in. After that I've run 115, 124, 125, 147 grain bullets without any problems. I can run 115GN reloads with 4.2 HP38 powder, 4.0 Titegroup, 4.2 Sport Pistol, and all function well...