williamwaco
04-01-2014, 01:51 PM
I am always experimenting - mostly to improve accuracy.
My favorite cast bullet rifle is my Japanese Winchester 1885 Highwall in .38-55.
It has six lands/groves
Bore Dia .368
Grove Dia .376
Max chamber at throat:
.396 No-Go Can't close action
.3955 Snug fit
.395 Easy contact
.394 No contact.
Average neck thickness measured = .09
.395 - .09 - .09 = .377 maximum bullet diameter for easy chambering.
Seems to work with case length <= 2.079
Will not close action with case length = 2.080
I started with 200 new Starline Cases
All my new cases were 2.080 +/-
First I fire formed them.
Trimmed them to 2.078
Then I outside turned the necks to .0085. This results in an outside neck diameter of .394 with the loaded case.
With the bullet sized to .3773. That is .0016 over groove diameter and results in a loaded cartridge diameter of .3943 which leaves a clearance of .0007 between the case wall and the chamber.
.0016 over groove diameter in my experience is too small but prior experience with this combination has proven to be workable.
The bullet is a Lyman 375449 Modified to 216 grains by cutting off the bottom band and grease groove.
This work was done by Erik Oehler at http://www.hollowpointmold.com
He does really nice work, really quickly and at very reasonable prices.
These bullets were sized without lube so there would be no possibilIty of the weight changing during the sizing operation. They were weighed into groups of +/- .1 grain when I got around 100 of them I hardness tested every one of them right in the center of the flat point. I kept only those that tested between 11 AND 12 BNH with the Lee tester. These were re-sized in the same die and Lyman 50./50 lube was added.
This bullet touches the lands at an overall seating depth of 2.587.
This leaves the entire crimping groove out of the case but all the lubrication groves are inside the case.
Doesn't matter because I am not gong to crimp them.
They were seated .010 deeper so they did not actually touch the lands.
I do not allow them to touch the lands because differences in case necks and bullet ogive diameter could change the seating depth.
The load was 9.1 grains of Unique weighed +/- 0.0.
The primers were very uniform but I select them for +/- 0.0 grains
They were CCI 200 primers and weighed 5.2 grains.
After the loading was complete and they were wiped clean, I turned them on my RCBS Case Master Concentricity Gaging Tool and kept only those with runout of .001 or less.
I took them to my favorite rifle range. It is a very small range, only 8 lanes but they are surrounded by a 20 foot berm on three sides: West, North, and East. Firing is to the North. The only way wind can get to your bullet is to blow on the base.
I posted my targets and started shooting. I don't believe in cleaning between shots so I cleaned before starting then fired three fouling shots using the same load with "normal - unprepared" cases to be sure I was on the paper.
After all the sorting, I had only 18 perfect match grade cartridges that passed all sorting steps.
For some reason, I don't really think it matters, I oriented each case in the chamber so the head stamped
( *------* "StarLine") was at the top.
I fired very slowly, not because the barrel heats up with that load but because I could see my heartbeat in the scope and waited until it was at minimum excitement. I have had the trigger "slicked up" so I can literally touch it off between heartbeats.
The range was 100 yards.
The results? Here is my 18 shot group.
101122
My favorite cast bullet rifle is my Japanese Winchester 1885 Highwall in .38-55.
It has six lands/groves
Bore Dia .368
Grove Dia .376
Max chamber at throat:
.396 No-Go Can't close action
.3955 Snug fit
.395 Easy contact
.394 No contact.
Average neck thickness measured = .09
.395 - .09 - .09 = .377 maximum bullet diameter for easy chambering.
Seems to work with case length <= 2.079
Will not close action with case length = 2.080
I started with 200 new Starline Cases
All my new cases were 2.080 +/-
First I fire formed them.
Trimmed them to 2.078
Then I outside turned the necks to .0085. This results in an outside neck diameter of .394 with the loaded case.
With the bullet sized to .3773. That is .0016 over groove diameter and results in a loaded cartridge diameter of .3943 which leaves a clearance of .0007 between the case wall and the chamber.
.0016 over groove diameter in my experience is too small but prior experience with this combination has proven to be workable.
The bullet is a Lyman 375449 Modified to 216 grains by cutting off the bottom band and grease groove.
This work was done by Erik Oehler at http://www.hollowpointmold.com
He does really nice work, really quickly and at very reasonable prices.
These bullets were sized without lube so there would be no possibilIty of the weight changing during the sizing operation. They were weighed into groups of +/- .1 grain when I got around 100 of them I hardness tested every one of them right in the center of the flat point. I kept only those that tested between 11 AND 12 BNH with the Lee tester. These were re-sized in the same die and Lyman 50./50 lube was added.
This bullet touches the lands at an overall seating depth of 2.587.
This leaves the entire crimping groove out of the case but all the lubrication groves are inside the case.
Doesn't matter because I am not gong to crimp them.
They were seated .010 deeper so they did not actually touch the lands.
I do not allow them to touch the lands because differences in case necks and bullet ogive diameter could change the seating depth.
The load was 9.1 grains of Unique weighed +/- 0.0.
The primers were very uniform but I select them for +/- 0.0 grains
They were CCI 200 primers and weighed 5.2 grains.
After the loading was complete and they were wiped clean, I turned them on my RCBS Case Master Concentricity Gaging Tool and kept only those with runout of .001 or less.
I took them to my favorite rifle range. It is a very small range, only 8 lanes but they are surrounded by a 20 foot berm on three sides: West, North, and East. Firing is to the North. The only way wind can get to your bullet is to blow on the base.
I posted my targets and started shooting. I don't believe in cleaning between shots so I cleaned before starting then fired three fouling shots using the same load with "normal - unprepared" cases to be sure I was on the paper.
After all the sorting, I had only 18 perfect match grade cartridges that passed all sorting steps.
For some reason, I don't really think it matters, I oriented each case in the chamber so the head stamped
( *------* "StarLine") was at the top.
I fired very slowly, not because the barrel heats up with that load but because I could see my heartbeat in the scope and waited until it was at minimum excitement. I have had the trigger "slicked up" so I can literally touch it off between heartbeats.
The range was 100 yards.
The results? Here is my 18 shot group.
101122