Originally Posted by 7mmRHB
Daveinjax, this is an overview of the process to form shortened cases.
The steps needed to make the 6.5 BPX from 6.5 x284 Lapua brass. Pushing the shoulder back .250 and lengthening the neck to .320.
1. Square case heads.
2. uniform primer pockets.
3. Deburr and chamfer flash hole.
4. Anneal shoulder and neck.
5. Lube inside of the neck, then expand necks to .290 with expander mandrel.
6. Lube the outside of the case and run it into Form Die #1.
7. Lube the new neck area again and run the case into Form Die #2.
8. Clean the cases inside and out.
9. Trim cases to 1.965 length.
10. Chamfer inside case mouth.
11. Aneal case necks.
12. Expand case necks with a .269 Expander mandrel.
13. Ream inside necks with a .280 reamer.
14. Expand w/ 7mm mandrel and outside neck turn to .014 neck thickness.
15. Chamfer outside of necks and polish inside with 0000 steel wool.
16. Lube cases inside and out, then run them into Form Die #3, 6.5 mm, with the expander ball attached.
17. Clean the lube off of the outside of the cases.
18. Expand neck to fir 6.5mm neck turn mandrel.
19. Turn necks to .0125 thickness. (.289 neck diameter with 140 Berger seated)
20. Chamfer necks inside and out.
21. Polish cases inside and out.
22. Fireform brass using 140 grain bullet with 40 gr. Varget.
23. Reprep brass to a trim length of 1.960
The 6.5 BPX is an improved cartridge design with minimum taper ( .0125 ) and 35* shoulder.
This was my original work list that has been changed a few times but gives an idea of the difficulty in shortening cases!! ---- 7mmRHB
I was looking over your forming process and had some questions.
1- How do you go about squaring the case heads? Never heard of this before.
2- Why do you anneal before working the brass. Isn't the Lapau brass already annealed?
3- I'm guessing you expand the necks out to .290 to make setting the shoulders back easier?
4- Why do you trim the brass before the final sizing and fire forming?
5- You expand the necks to .269 and use a .280 reamer?