Fireforming the 284 Shehane with COW

[kyreloader]

I have been shooting the 284 Shehane for over a year. I fireformed the cases that I am shooting now by loading with 284 data and shooting the cases normally. By doing that, the second/third firing of the brass I had the formation of a doughnut in most of my cases. I had to ream out the neck and re-turn to get rid of it.

I recently bought 100 new 6.5x284 Lapua cases that I need to fireform to 284 Shehane and I would like to use the COW(cream of wheat) method to fireform. I have a couple questions for the COW fireformers here on the site.

Particulars: I have a .313 neck and my loaded rounds are .310, making my neck thickness of the Lapua cases 0.013.

1. Can I turn the neck to the needed thickness(0.013") as a 6.5 case and then fireform with COW? Will the stretch then make the neck too thin? Should I turn to 0.015 or 0.016, fireform with COW, then turn with a 7mm mandrel to get to final neck thickness?

2. Should I fireform with COW then expand to needed internal neck diameter(small neck will make the ID of a FF round less than 7mm), then turn? (Seems like that would set me up for a doughnut?)

What order do you guys turn/FF your cases to avoid the doughnut?

How do you avoid a doughnut to your cases?

Thanks in advance.

 

[kyreloader]

Bump to top for more help.

 

[RDavies]

Definitley dont neck turn while necked down. If you do this, when you neck it back up, some unturned portion will become part of the neck. If anything and you want to be absolutley sure of no donuts, you would want to neck up to 30 cal, neck turn, then neck down to 7mm. If you just want to neck up to 7mm, then use normal bullets in fireforming, and load them with lots of jam. This will keep your case back against the bolt, so if there is any donut, it will be kept back in the shoulder.

 

[kyreloader]

Thanks CR500.

So you recommend not using the COW method for fireforming?

Reason I ask, if I use COW method, I can do it at my house and would not use range time fireforming cases. Also, I do not think I want to use up valuable barrel life fireforming other cases.

Wish I could neck up to 30 caliber, but that would necessitate another die in 30 caliber to neck up with and also another mandrel to turn once I get to 30 caliber. I would still worry about what neck thickness to turn to at 30 caliber because I would be worried about sizing back down and getting a thick neck.

What are your thoughts?

 

[kyreloader]

Well, I am just going to load them up with pistol powder, COW and a patch and fireform them to my chamber. I will expand the cases, then neck turn them to the needed diameter. I hope that works out ok. I believe I will probably have doughnuts whichever way I do it, so this seems the easiest on the barrel.

Thanks to those that read.