Good timing... I just purchased a barrel chambered in 280 RCBS with dies marked 280 Improved 30 deg.
It's a shouldered barrel I need to install on a Rem 700 LA. How would i go about head spacing it correctly? also, can I fire form 280 Rem brass with it then reload with the dies?
Not answering your questions, but do you have fired cases from it? A friend has a 1937 M70 Super Grade with "7mm" marked on the barrel. It was originally a 7x57 but had been wildcatted probably in the 50's or 60's. Our best guess based on a lot of research was 7-06 RCBS Improved (30 deg shoulder). If you're not positive, consider doing a chamber mold with Cerrosafe, etc.
https://www.brownells.com/gunsmith-...osafe-chamber-casting-alloy-prod384.aspx
