Problem With RCBS 300 mag Die

forrest-hunter · November 24, 2018, 01:43 PM

Have 4 brass that do not hold 180 gr remington corelok bullet after running through RCBS small base seating die - had no problem rest of brass and bullets reloaded - checked bullet diameter and they where ok -can't figure out what is wrong with brass - ran them through resizer again - still no luck

**Unclenick** · November 24, 2018, 02:44 PM

They need the necks annealed. The necks have work-hardened and become springy, so they aren't staying the size of the die. Small-base dies work the brass harder than standard dies, so this happens faster with them. If the cases are Remington cases, too, I'll add that I used to have this same problem with Remington-Peters 45 Auto brass. It was a combination of work-hardening and the necks being a couple thousandths thinner than most other brands so the die wasn't squeezing the ID down as far by that same 0.002". But regardless of who made them, annealing is what will fix it.

forrest-hunter · November 25, 2018, 11:47 AM

Thanks - have annealed 218 Bee brass to help with split necks - did not know about this

reynolds357 · November 25, 2018, 05:19 PM

Unclenick is most likely correct. The other option is that the neck material has become too thick and needs inside reamed or outside turned. With a standard die, it is not possible for that to be the case, but it happens regularly when match dies are set up a certain way.

forrest-hunter · November 27, 2018, 01:15 PM

annealed the brass causing problem last night - reloaded them with no problem -

November 24, 2018, 01:43 PM	#1
forrest-hunter Junior Member Join Date: March 6, 2018 Posts: 5	Problem With RCBS 300 mag Die Have 4 brass that do not hold 180 gr remington corelok bullet after running through RCBS small base seating die - had no problem rest of brass and bullets reloaded - checked bullet diameter and they where ok -can't figure out what is wrong with brass - ran them through resizer again - still no luck

November 24, 2018, 02:44 PM	#2
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,061	They need the necks annealed. The necks have work-hardened and become springy, so they aren't staying the size of the die. Small-base dies work the brass harder than standard dies, so this happens faster with them. If the cases are Remington cases, too, I'll add that I used to have this same problem with Remington-Peters 45 Auto brass. It was a combination of work-hardening and the necks being a couple thousandths thinner than most other brands so the die wasn't squeezing the ID down as far by that same 0.002". But regardless of who made them, annealing is what will fix it. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

November 25, 2018, 05:19 PM	#4
reynolds357 Senior Member Join Date: December 10, 2012 Posts: 6,165	Unclenick is most likely correct. The other option is that the neck material has become too thick and needs inside reamed or outside turned. With a standard die, it is not possible for that to be the case, but it happens regularly when match dies are set up a certain way. Last edited by reynolds357; November 25, 2018 at 05:24 PM.

November 25, 2018, 11:47 AM	#3
forrest-hunter Junior Member Join Date: March 6, 2018 Posts: 5	Thanks - have annealed 218 Bee brass to help with split necks - did not know about this

November 27, 2018, 01:15 PM	#5
forrest-hunter Junior Member Join Date: March 6, 2018 Posts: 5	annealed the brass causing problem last night - reloaded them with no problem -