I have a Colt Cobra and DS. The only ammo I have been able to find lately is Winchester White box 150 grain lead round nose, which I have been using. Will these bullets cause fouling in the barrels? And this may seem like a stupid question but how can I tell if there is lead fouling? I have a bore light but don't know what lead fouling looks like. I am new to revolvers as you can probably tell.