Forming 9x25 Dillon.

[gnappi]

Thanks again. That 1700 fps 125 grain load is pretty impressive. With powder prices still so stupid high I'll likely get some longshot if / when prices stabilize. Down here I'm still seeing $75 per pound, a good reason to use up my AA powder.

[Maz2331]

I've just done my first box of 9x25 rounds and did get my shoulders pushed back just a little bit too far when I formed the cases, which caused me to have a couple of light strike misfires.  I used the empties from rounds that did fire properly to readjust the sizing die to just barely touch the shoulder and that problem won't happen again.  After all, a fireformed case is the best way to adjust the die to your gun's chamber.

As for the neck splits, my theory is that those are caused by overworking the brass without annealing it at the right step in the process.  Perhaps the best time to do an anneal on these cases is right after necking them down the first time - that will prevent the splits seen when expanding them. 

My load workup was guided by Quickload software, and this cartridge actually seems to match the software almost perfectly.  I used Sierra 115 grain SportMaster JHP's loaded at 1.26 inch and worked up to 11.5 grains of Power Pistol powder.  Average velocity of that load was 1688 fps, low of 1671 and high of 1701 with mixed headstamp "FC" and "Blazer" brass cases with small primer pockets, and CCI 500 small pistol primers. 

[sqlbullet]

I had my first round of neck splits this past week.  I was picking out some brass for some test loads from my once fired bin, needed five and had five nickel cases on top.  Four of the five split, so I think I will avoid nickel cases in the future.

[gnappi]

I had my first round of neck splits this past week.  I was picking out some brass for some test loads from my once fired bin, needed five and had five nickel cases on top.  Four of the five split, so I think I will avoid nickel cases in the future.

Good plan. Back in the day using plated brass to form was anathema to wildcatters for just that reason, or so they said.

Anyway I don't use nickle brass or anneal and have so far had very few splits. I have so much used 10mm brass (I have two 5 gallon pails and just found another 2k new) even if annealing saved me an additional 1-2% the labor and time to anneal are not worth the effort.

[Maz2331]

Nickel plated cases are notorious for splitting when over-worked.  Without necking down they will still split far more frequently and at a lower number of loadings than plain old brass in the 10mm.  And you just can't anneal the nickel layer like you can with brass.