alternate to chambercast

[Kragman71]

Hello
Someone here,had supplied instruction to get an impression of the foreward part of the chamber.
It included filling an unssized case with a leadalloy and cutting the neck off at the shoulder.This was then chambered in the gun and a pure lead slug was hammered into it,to get the impression.
I recently bought a firelapping kit from Beartooth Bullets,and an instruction booklet came with it.
They included the same directions for getting the cchamber impression;except that it did not include cutting off the case neck.
Can someone explain the reason for cuttting off the neck?
thanks
FRank

[slughammer]

I have not seen the recommendation to cut off the case neck, but perhaps it is so the lead will fill the neck area of the chamber for an accurate measurement.

I use a case filled up with WW and then about 1/4 to 3/8 of an inch poured out. I then use a pure lead slug. When the slug is expanded the case neck also expands and gives a fair measurement of the chamber neck.

Another good method for the chamber neck for a 30 bore is to drive a 38 wadcutter up into the chamber neck and the throat/lead in area. Easy to do 3 quick and then have some measurements to average.

[Kragman71]

Slughammer
Thanksfor the response.
Actually,the instruction sheet was from a link provided from this Forum.
I'll leave the neck on.
Frank