The Firing Line Forums - View Single Post - First run .308 win. work up. Please check my work.

wrightme43 · January 13, 2013, 12:59 PM

Ok, I have a Lee breech lock kit. RCBS dies. Central Mach. Micrometer.

I have 7.62x51 CBC brass 2012 manufactured, I fired in my Ruger Gunsite Scout.

Lubed cases, full length resized, deprimed, swagged the primer crimps, resized to 2.008. (that is where my lee resizer stops and will cut no further) Hand polished cases, and beveled inner and outer neck.

Primed 2 sacrificial cases, measured grains of water. 54.4 grains of water. pretty dog gone close to the others I have read on here. Still starting low of course. I disposed of these cases.

Primed all cases with remington large rifle primers untill the primer was flush.

Using IMR 3031 and Hornady 150 grain BTSP I found loads using EDIT hornady load data book. EDIT I did not find 3031 in the hornady book for 150 grain btsp. I found that data at the IMR/Hogdon website.
Start load, 40.2, max load 43.5 Compressed

Bullet 150 grain BTSP

I wieghed all loads light after zeroing the scale and trickled up to the load.
I made
1 round @ 39.2 and labled it with a sharpie.
1 round @ 39.7 and labled it with a sharpie
3 rounds @ 40.2 and labled them with a sharpie
3 rounds @ 40.7 " "
3 rounds @ 41.2 " "
3 rounds @ 41.7 " "
3 rounds @ 42.2 " "
3 rounds @ 42.5 " "

I then seated all the bullets, COL is 2.770-2.775 based on deformation of the soft point.

My reasoning is this. I will start with the lightest loads, and work my way up, checking for any problems after every firing.
The max loads/never excede loads are all compressed loads, with this bullet, in a longer overal cartridge length. 2.800 max.
Since none of my loads are compressed, and I have a slightly (very slightly) smaller case capacity than lapua, or norma brass, I should not excede any pressure levels that can cause harm. Is this thinking correct?
I worked up to a 42.5 grain load because it is a Chuck Hawks pet load, with that powder and tha wieght and style of bullet.

I am not exactly following the Optimal Charge Wieght load plan. I will follow this as soon as I can, but I wanted to test these first.

Here is the Optimal Charge Weight link http://optimalchargeweight.embarqspace.com/

The basic concept (you guys most likely all know this but just in case) is that, if the bullet exits the barrel while the shock wave that travels up and down the barrel is at the crown it will make fliers, and if it exits as it at the breech the barrel will be more stable and produce more accuracy.

Its a neat idea. Maybe its all bunk. I dont know. I am really really really new to this. I keep good records and like to experiment so I am just going to see what happens.

Now if I have done something stupid please tell me. If you have a idea I would love to hear it.
Thank you
Steve

January 13, 2013, 12:59 PM	#1
wrightme43 Member Join Date: January 5, 2013 Location: Bowling Green KY Posts: 37	First run .308 win. work up. Please check my work. Ok, I have a Lee breech lock kit. RCBS dies. Central Mach. Micrometer. I have 7.62x51 CBC brass 2012 manufactured, I fired in my Ruger Gunsite Scout. Lubed cases, full length resized, deprimed, swagged the primer crimps, resized to 2.008. (that is where my lee resizer stops and will cut no further) Hand polished cases, and beveled inner and outer neck. Primed 2 sacrificial cases, measured grains of water. 54.4 grains of water. pretty dog gone close to the others I have read on here. Still starting low of course. I disposed of these cases. Primed all cases with remington large rifle primers untill the primer was flush. Using IMR 3031 and Hornady 150 grain BTSP I found loads using EDIT hornady load data book. EDIT I did not find 3031 in the hornady book for 150 grain btsp. I found that data at the IMR/Hogdon website. Start load, 40.2, max load 43.5 Compressed Bullet 150 grain BTSP I wieghed all loads light after zeroing the scale and trickled up to the load. I made 1 round @ 39.2 and labled it with a sharpie. 1 round @ 39.7 and labled it with a sharpie 3 rounds @ 40.2 and labled them with a sharpie 3 rounds @ 40.7 " " 3 rounds @ 41.2 " " 3 rounds @ 41.7 " " 3 rounds @ 42.2 " " 3 rounds @ 42.5 " " I then seated all the bullets, COL is 2.770-2.775 based on deformation of the soft point. My reasoning is this. I will start with the lightest loads, and work my way up, checking for any problems after every firing. The max loads/never excede loads are all compressed loads, with this bullet, in a longer overal cartridge length. 2.800 max. Since none of my loads are compressed, and I have a slightly (very slightly) smaller case capacity than lapua, or norma brass, I should not excede any pressure levels that can cause harm. Is this thinking correct? I worked up to a 42.5 grain load because it is a Chuck Hawks pet load, with that powder and tha wieght and style of bullet. I am not exactly following the Optimal Charge Wieght load plan. I will follow this as soon as I can, but I wanted to test these first. Here is the Optimal Charge Weight link http://optimalchargeweight.embarqspace.com/ The basic concept (you guys most likely all know this but just in case) is that, if the bullet exits the barrel while the shock wave that travels up and down the barrel is at the crown it will make fliers, and if it exits as it at the breech the barrel will be more stable and produce more accuracy. Its a neat idea. Maybe its all bunk. I dont know. I am really really really new to this. I keep good records and like to experiment so I am just going to see what happens. Now if I have done something stupid please tell me. If you have a idea I would love to hear it. Thank you Steve __________________ “Must be yearning deep in human heart to stop other people from doing as they please.” ― Robert A. Heinlein Last edited by wrightme43; January 13, 2013 at 02:03 PM.