23 October 2005, 21:32
hglassBrass Volume??
My general question is: Is there a difference in volume between Norma brass and Winchester or Remington brass.(I've been using Norma)
My reason for asking is as follows: With my 7x57 M98, my loads always seem to be hot. I don't have this problem with any other rifle I reload (aprox 8 different cals.) I usually am .010-.015 off the lands. I use manuals and quickload for guidance. Any advice would be helpful.
Any good loads for a 140 grain Partiton for the above cal. would be appreaciated.
23 October 2005, 23:24
schromfquote:
Norma brass and Winchester or Remington brass.(I've been using Norma)
My data points are all on my old stuff, I haven't bought any 7x57 in years, so new generation brass could be different.
The old R&P brass had the smallest case volume with 52 grs water capacity
In the Middle is Norma brass with 53 grs
Winchester brass has the most volume with 54.2 grs
These are ish numbers but you get the drift the Norma has a case smaller volume than the new Winchester, so you need to adjust your powder charges just a tad downward for the same velocity.
Your talking tenths of grains on your powder charge though.
When you say your charges are "hot" are you getting pressure indications?
23 October 2005, 23:49
mhoWeigh the brass, or measure volume with either water or fine corned solid substance (e.g. a ball powder).
- mike
24 October 2005, 04:50
asdfWeigh the brass and divide the difference in weights by 8.5 to get the difference in water capacity. The 8.5 is the specific gravity of cartridge brass.
To try to keep the pressures the same between different brass lots, keep the density of loading the same. This is the ratio of the charge weight to the water capacity (gn water)
below the seated bullet.
24 October 2005, 04:56
Ralph HyrlikIn 22-250, Norma has less capacity than RP and requires one grain less powder to reach the same pressure.