7.62x39 converted to 6.5 Grendel not chambering

[CPC24]

I have lots of RP, FC, and Win x39 brass now. Converted and fireformed, it’s right at 35gr H2O. I scrapped all the PPU.

[ackleyman]

I made at least 10K of 6 & 22 PPC brass out of PMC 7.62x39 brass. Win, Rp, FC was junk excpept on light loads and the ppc's like to run some pressures.

[Dapaki]

My son picked up a BCA Grendel upper and we finally got into the shop to form some Grendel brass from 39 brass. All my 39 brass is separated by manufacturer so we stated with R-P and immediately rolled the shoulder into the case so that was a no-go.

FIOCCHI was next but we experienced over sized heads that the sizing die created a band around the case head so that also was a no-go.

Next up was S&B but that was just like the FIOCCHI with head width problems leaving a belt just above the extractor groove.

Winchester brass was about 50/50 with good forming, some rolled shoulders so we abandoned them in favor of trying one more brand.

We settled on Federal brass with 100% success in forming them, all measurements were good, the head cleared the die with no brightening or swageing/belt forming.

We have no Lapua, PPC or Hornady brass to try so FC is going to be the brass of choice for now. Thanks for the thread to the Grendel history, that was very informative.