Blast gun recommendations

I don't think the problem is the white tips.
The issue you will see is the gun it is softer than the tips.
Tear the gun apart, you will see the sand path eroded the metal in the gun.
The metal eats away around it and will destroy an tip.
I have a white tip in my blast cabinet and it is still works, had to add some brazing rod to the metal on the gun to keep it working. Never changed the tip, but the media has been changed alot.

FYI just buy a cheap Tractor Supply hand held gun for $15 and throw it in the cabinet.