Originally Posted by DigitalDan
Quote
Never dreamed .001" would make that much difference.

Couple of thoughts come to mind. Did you wipe the bore with a wet patch before trying to seat the .501" bullet? It's a common routine.

Do you know the hardness of the alloy those bullets are made of?
This

I was the one who suggested No Excuses. I don’t get too torqued up about them being a tight fit going down. They will bump up to the correct diameter easily when fired. But I do wipe the bore between shots for shot to shot consistency

You only live once, but...if you do it right, once is enough.