.40 unique 180gr XTP Data?

BarbreJ · January 9, 2011, 05:46 PM

I got some 180gr Hornady XTP's for Christmas and some Unique.

Checking my Lyman book it shows min: 4.9 and Max: 5.6, but on the Alliant website it shows 6.7gr so even if I drop it 10% thats still a staring charge of 6.0gr.

The Alliant data is for Speer GDHP, and the Lyman book is for 180gr Jacketed HP. I know I am new but is there that big of a difference between two different bullets that as far as I know are the same thing basicaly?

I am sure the right answer is start at 4.9gr and work my way up till I am happy with the load, but it got me thinking because for my 165gr Rainer/Berry's I have been using the 165gr TMJ data in the Lyman book...with no issues, and thought as long as I wwas using data from the same kind of bulltet, I was good to go.

Thanks,
John

Is it ok to use a similar bullets data as long as you start at the bottom and work up?

jmortimer · January 9, 2011, 05:48 PM

I go with Alliant's data. If it were me I would go with 6 grains of Unique. If you are at the upper end of Unique data you get cleaner gun and better accuracy.

BDS-THR · January 9, 2011, 06:10 PM

+1. I tend to go with the latest published (paper or web) load data from powder manufacturers.

Some powder manufacturers do vary powder formulation and load data have changed over the years for some powders. If there's any change in the formulation, powder manufacturers would be the first to change the load data.

Stick_man · January 9, 2011, 06:41 PM

When using data for one bullet that specifies a different make of bullet, remember that not all bullets of the same weight are the same. Measure overall length of the bullet itself, and of the COL of a loaded round. Different makes need to be seated to different depths and therefore could result in unwanted pressure spikes. If you have two same-weight bullets that are the same length and need to be seated to the same depth, you should be good to go with that data. If different lengths, be extra careful about what loads you use.

Good luck and be safe.

BarbreJ · January 9, 2011, 09:12 PM

Good info as always guys!

Thanks again,
John

January 9, 2011, 05:46 PM	#1
BarbreJ Member Join Date: June 5, 2010 Location: St. Louis Posts: 59	.40 unique 180gr XTP Data? I got some 180gr Hornady XTP's for Christmas and some Unique. Checking my Lyman book it shows min: 4.9 and Max: 5.6, but on the Alliant website it shows 6.7gr so even if I drop it 10% thats still a staring charge of 6.0gr. The Alliant data is for Speer GDHP, and the Lyman book is for 180gr Jacketed HP. I know I am new but is there that big of a difference between two different bullets that as far as I know are the same thing basicaly? I am sure the right answer is start at 4.9gr and work my way up till I am happy with the load, but it got me thinking because for my 165gr Rainer/Berry's I have been using the 165gr TMJ data in the Lyman book...with no issues, and thought as long as I wwas using data from the same kind of bulltet, I was good to go. Thanks, John Is it ok to use a similar bullets data as long as you start at the bottom and work up?

January 9, 2011, 09:12 PM	#5
BarbreJ Member Join Date: June 5, 2010 Location: St. Louis Posts: 59	Thanks, Good info as always guys! Thanks again, John

January 9, 2011, 05:48 PM	#2
jmortimer Junior member Join Date: January 24, 2010 Location: South West Riverside County California Posts: 2,763	I go with Alliant's data. If it were me I would go with 6 grains of Unique. If you are at the upper end of Unique data you get cleaner gun and better accuracy.

January 9, 2011, 06:10 PM	#3
BDS-THR Senior Member Join Date: June 12, 2010 Posts: 479	+1. I tend to go with the latest published (paper or web) load data from powder manufacturers. Some powder manufacturers do vary powder formulation and load data have changed over the years for some powders. If there's any change in the formulation, powder manufacturers would be the first to change the load data.

January 9, 2011, 06:41 PM	#4
Stick_man Senior Member Join Date: October 18, 2008 Location: Salt Lake City, Utah Posts: 241	When using data for one bullet that specifies a different make of bullet, remember that not all bullets of the same weight are the same. Measure overall length of the bullet itself, and of the COL of a loaded round. Different makes need to be seated to different depths and therefore could result in unwanted pressure spikes. If you have two same-weight bullets that are the same length and need to be seated to the same depth, you should be good to go with that data. If different lengths, be extra careful about what loads you use. Good luck and be safe.