Lee Enfield No. 4 Mk I - Seeking Info

[Parashooter]

Based on what I found while cleaning, I'd say the rifle has been shot before so hopefully it's still safe to do so. I'll have to see if there's a local gunsmith knowledgeable on the Lee Enfields that can check it out. I've otherwise had a hell of a time finding the gauges here in the U.S. I've found a few (expensive) ones, but they are SAAMI spec and what I've read leads me to believe I need those made to Britishicon "military spec." Does anybody have any leads on some gauges?

Before going crazy over headspace, take a look at this article - https://www.milsurps.com/content.php...101-for-.303-s