Just some background, I've put together a lot of SA Savages, but this is my first time owning a belted magnum 300WM.

I went to the range today to shoot my rifle for the first time. I loaded the ammo using once fired FC brass using Hodgdon's 3.42" COL. Dummy me didn't cycle the rounds prior to heading to the range.

While I'm at the range, the bolt will not close for me. I have dry fired the rifle a few times with an A Zoom snap cap and when using the snap cap, the bolt would close.

Would I be correct into thinking that headspace my be my issue? I have a GO gauge, but the company I bought my GO gauge was out of NO GO gauges, so I used the tape method to simulate the NO GO gauge.

When I came home from the range, I went to my reloading room and grabbed a virgin Winchester brass case. With the Winchester case, I was able to get the bolt to turn, but I could not get it to close.

I'm thinking it's a headspace issue or the brass needs to be FL sized.

I suppose it could be an ammo issue, but the ammo is in spec in terms of case length and OAL.

Please advise me of any suggestions to resolve my issue.