Easy ID

[elkermarty]

I am shooting a 300 Win mag now. I just had a rifle rebarrled to 338 for a back-up rifle. You never know when you might need it. My question is, I need a good way to tell the 300's from the 338's when it is early in the morning and there is not much lite in the tent. I want to load both with Nosler Partitions so the bullets will look the same, so that will not be any help. You know us old people do not have the best eyes in the world.
Any suggestions?