Quote:
Originally Posted by Spawndn72
I am confused.
For a 158 grain lead SWC Accurate shows a starting load of 9.1g and a max of 10.1 as follows
"158 (L) LC SWC 9.1 1,041 / 10.1 1,183 33,228 1.580"
Lyman 49th edition shows doesn't have a 158 grain, but it goes have a 155 grain which I would think would at least be close, but it shows:
"155 (L) SWC 10.8 893 28,300 / 12.0 1146 41,300"
How in the world can the be that far apart?
|
I have noticed the discrepancies since 1967....and after 50 years there are still discrepancies but there are just so many variables..
One of the reasons Lyman's might be different is the bullet they used. the 155 gr. SWC #358156 is cast of hard Linotype (BH hardness 22 to 24)and fitted with a Gas Check . The accurate bullet is a Laser Cast lead , bevel based (no gas check) bullet , according to their site BH hardness is 24.
So although the bullets are quite similar...that little copper cup on the base of the Lyman allows it to be loaded to a bit higher velocity. The plain bevel base of the laser cast is a minor difference but could explain the discrepancies....
Then again...I could be totally wrong...maybe the guys at Lyman are just more "adventurous" in their testing ????
I cast and load the #358156 in 357 magnum with accurate #5 and have not found Lyman's data to be excessive with this bullet, hard cast and gas checked.
I would use Accurate data with softer cast plain or bevel based bullets.
About all we can do is pay attention to the variables , use the data that fits the components we are using and use some good old fashioned common sense.
The little details can and do matter...sometimes a lot so pay attention to the details.
Gary