1st time pressure test

[Mikecr]

All of this & more demonstrates that overall you cannot credit powder loads until cases are fully fire-formed and taken to stable.
So stop going to max loads and complete the basic task of fire-forming, in a rational way, that does not expend a lot of efforts and mangle your cases before they're even useful.
You've likely opened primer pockets a bit already, and have no progress with the brass. Just problems.

 

[couesaddict]

Taking advice from here I fire formed 30 cases today. Good reason to burn up powder and bullets you don't use. Shoulders moved .015 bringing them very close to bumping length. I'll clean and resize, back down to 74G and start again.
One last question on this. The two pieces of brass that showed pressure signs I had trouble with even after full resizing. They slid in OK bolt opened and close was smooth. But sliding the bolt back was sticky on one and worse on the 77G shell. After cleaning with stainless media all returned to normal. What gets fubared when you can't slide the bolt back ?

Your sizing die doesn't size all the way down to the belt. It's possible pressure got high enough that it swelled the web area enough it didn't spring all the way back down after firing. Measure that area just above the belt on those cases and I'd bet they're larger than the rest of them, causing them to still be sticky in your chamber. If primer pockets are still ok I believe they make a collet die to address that issue but probably not worth it for two cases.

 

[ResearchinStuff]

The Forster bushing bump die actually doesn't size the body of the case at all, it just sets the shoulder. You need to add a redding body die to actually resize the case if you're going to be running high octane loads. Set it up so it just kisses but doesn't move the shoulder, and run it before you use the forster die to set neck tension.

https://www.midwayusa.com/product/420044/redding-body-die

 

[ForeverZ01]

Check out the Larry Willis collet die so you can bump that belt back