Fire form or not?

[MVW]

Some folks suggest neck turning before firing. Others suggest fire forming first. I heard that the later is responsible for the formation of donut. Can someone set me straight on whether I should shoot first or turn first.

Thanks, Mike

 

[dmickey]

If you have a tight neck chamber, you may not have any other choice than to neck turn first as the case may not fit into the chamber without it. This was the case with my 6mm BR. And that was before a bullet was seated!

 

[Bulseyetom]

I just got a wildcat based on the 30-40 Krag necked down to 7mm and then blown out. I fireformed 20 cases after neck turning and 10 cases after fireforming to see which way worked best. I used creme of wheat and not a bullet for the first time as well. My results were not conclusive but I believe that I will neck turn first from now on as it seemed somewhat easier to adjust the depth of the cut before the shoulder angle was blown out. I might add that I am waiting on my custom sizing die and had to use a 7x57 mauser die to size the necks down from the parent brass to form a false shoulder to headspace on. The resulting shoulder has an angle of 20 degrees or so and my cutter is a 40 degree cutter so it quits cutting when it gets to the junction. The cases that I fireformed where still slightly rounded and it was difficult to cut right to the junction of the neck and shoulder. I am sure that after a few firings that the angle will be sharp and eliminate that problem but it is a tight neck and I have to turn before firing a bullet anyway. Tom

 

[Zia Hunter]

I neck turn before fire forming my new brass.

 

[lpreddick]

runout measured in new brass necks can disappear after fireforming. neckwall thickness variations might improve after fireforming. i believe neck turning will give you more precise brass if done after fireforming for these reasons. you can always turn very lightly, fireform, the turn more completely.

 

[fguffey]

MVW, “Others suggest fire forming first. I heard that the later is responsible for the formation of donut” the later read/heard most likely came from this forum, simply put, they do not know what causes do-nuts and a few do not want anyone else to know, it would help to know what cases you are firing and what chamber the cases will be fired in. I form first then fire, when I extract my fired cases the are extracted as once fired.

Again, do-nuts, I make donuts, I create do-nuts at the shoulder neck juncture without ever firing the case, there is nothing I can do to a case that will prevent do-nuts at the shoulder neck juncture, I have chambers that have never created a do-nut, I have other chambers that I am guaranteed will develop do-nuts.

I should caution you, I come with baggage, my baggage reminds me of an Alabama Leg Dog my son gave my wife, long story, I contacted bluebamapits.com, they put me in contact with the help desk, what a tech department

F. Guffey

 

[stretch308]

Whether before or after I'm not sure how or why the "donut" would appear if using sufficient loads and only turning actual neck length.