Brass Spring back?

[valerio024]

I recently acquired a 375 JDJ barrel for my T/C Encore. The brass is made by sizing down .444 marlin cases to .375. It's supposed to be a single pass through the die. Yesterday I sized a bunch of cases and checked fit in my rifles chamber. All went in without issue. So today I loaded some up only to find that the majority no longer seat in the chamber. Is this issue due to brass springbuck? Any tips for the next time around? I suppose I'll pull all the bullets and powder and run them through the resizing die again and hope that takes care of it.

 

[Koda_]

I can only guess your getting some level of springback but if your sizing up or down you should be annealing before and probably after to prevent springback and assure consistent neck tension.

Some good info on this: https://bisonballistics.com/articles/case-neck-tension-a-stress-analysis