Shoot the Dardas bullets in the SIG and get some .401s from Missouri Bullet Co. for the XD and Glock. Your cast bullet needs to run .001" larger than the groove dia. of your barrel. Don't quite understand why you got leading from the Dardas bullet in the Lone Wolf barrel. I have shot .402" cast lead bullets with no issues. You just have to be more careful in load development and not load as high in chargeweight as you could for a .401". You really should be able to use a .402" cast bullet for all 3 pistols if you hold them to mid level charges. Velocity and Brinell hardness shouldn't really be a factor unless you were pushing them very hard. I believe I've heard folks say that if you can wait just a bit longer, Missouri Bullet will custom size your bullet order.
