I put a 338 federal barrel on a savage striker action the other night and I used sized brass to set the headspace. No problems, I got a slight resistance to FL sized brass, crush fit with a single layer of scotch tape on the case head, and no go with two layers of tape.

My question is this. I used virgin Lapua 308 win cases to make the 338 fed brass. Any gotchas out there with using brass sized up from 308 to headspace the new caliber? Anything specific I should check before lighting the first round off, on account of being extra careful?

TIA

I would expand the .308 necks to .35 caliber, then run them into the .338 die thus creating a small secondary shoulder, trying them in the chamber until the bolt closes with some resistance. That, or just do what you did and neck them up to .338 and be done with it- it sounds like you're good to go.

Or you could just buy Starline .338 brass. $145 for 250.

https://www.starlinebrass.com/order-online/index.cfm