Fire Forming Brass Question

[bns454]

Hi Guys,I need to reform some 30-06 brass into 8x57 to tighten up a mile of neck/chamber clearance.I never did this before.Do the cases grow or shrink when you fire form them?I guess I dont want a large gap from the case mouth to barrel for lead to flow into.If they grow upon firing and bottom out lengthwise i suppose thats bad too.Help.

 

[fiver]

shrinks.
I use a 100% full jacketed loads to fire form my cases.
it sets things all the way to the corners and aligns the re-worked brass properly.

 

[Ian]

Do the Scotch tape trick while you're at it to keep the body and head concentric.

 

[bns454]

Thanks guys.

 

[dale2242]

The Scotch tape trick??????
Tell me about it...dale

 

[fiver]

scotch tape is about .002 to .0025 thick.
you use a wrap of it around the re-formed case to hold it up and more central to the centerline of the barrel then fire form.
then remove the tape for the next loading.
you can also use 1-2 wraps around the neck to hold it in place to insure the body of the case is in alignment better.
otherwise the case is just lying on the bottom of the chamber and it swells up and out more than in all directions.
it is eventually pressed in all directions by the pressure anyway, but the first initial stretch will push away from the supported area at the bottom, and if the case is in the chamber crooked it will take the shape of the chamber crooked.

 

[JSH]

I went about it a bit different. I did the scotch tape, it worked but was a bear to get to ft the case, may be the brand.
I went up one caliber, then necked back down until I had some crush on the false shoulder.
I used a cast bullet. It did engrave on the lands and was actually was seated upon closing the bolt.
I annealed cases before firing.
I still had to square up the case mouths after firing.
I used once fired LC brass. I later found some pull down LC brass.
Worked great. Buddy is still using it in his rifle.
Jeff

 

[Ian]

The Scotch tape trick??????
Tell me about it...dale

Cut a strip about 3" long and 1/8" wide with scissors. Wrap around the case head, just in front of the extractor groove. Don't overlap the tape ends unless there's room for another full wrap, make either one layer, or two, or three to make an even thickness of tape that will center the case head better in a loose chamber.

 

[bns454]

How would leaving a bell the correct size on the case neck work for centering it.If not the tape is a good idea.Dont know if anyone ever tried the bell idea,just asking.

 

[Brad]

Bell centers the neck but not the case head.

 

[bns454]

I will tape the head end,I am being lazy,didnt want to tape both ends is all.

 

[fiver]

anything to hold it central is best.
I have seen all kinds of different methods.
just sticking it in there and shooting it works of course.. but,, you know.