jhibbard24
Well-Known Member
how much weight variation is allow-able in weight sorting brass. any special processes before weighing (prepping, trimming, etc.). lets hear some input
how much weight variation is allow-able in weight sorting brass. any special processes before weighing (prepping, trimming, etc.). lets hear some input
Forget shortcuts. Case weight in itself is meaningless.lets hear some input
You are 100% correct and in short anyone who says different is just plain wrong period.
Sorry BH but I have to disagree.
When cases are sized the same and prepped the same differences in weight indicate
differences in wall thicknesses that will vary case volume. the only dimensional differences
will be differences in extractor grove depth and there is little or no difference if it is quality
brass or of the same lot #
Volume testing these different case weights have confirmed that it will show different volume's
to a reasonable accuracy.
Volume testing is very slow and if not done correctly will give false volumes and will not be as
accurate as weight sorting .
Weight sorting is much easier and with good electronic scales very accurate and most people
will not get discouraged with the process.
Like everything else, consistency is the name of the game and anything that will make brass
more consistant will improve accuracy.
When I started shooting (Over 50 years ago) I simply full length sized and loaded. As I improved
in my shooting skills I found my reloading to be inadequate and with every step accuracy improved
and scores climbed. I have since found through testing different methods that my ammo was more
consistant and some things do make a difference, and that good ammo takes work.
When I started loading ammo, there were full length sizing dies and neck sizing dies. Now there are
specialty dies that adjust neck tension,shoulder to case head dimensions.micrometer adjustable
bullet seaters and so on. Most of the serious shooters use them and anything else that will improve
there odds of a clean one shot kill or a winning score, and some will tell you that they just load and
shoot so they don't have to share there secrets to good performance with you.
It is true that if a person hunts under 200 yards it doesn't make that much of a difference as long as
the rifle will shoot 1 minute of deer, But if they want 1/2 MOA at all distances, every thing makes a
difference.
This is just my opinion and just because someone does not agree with me does not make him wrong
it just means that he disagrees.
J E CUSTOM
Well if that is your opinion then you are certainly entitled to it. Just because you do not have the means to accurately measure the internal volume that is a process issue that you must resolve. I myself was skeptical of this at first because I wanted an easy way to measure the interior volume of cases. My smith who is a HOF Shooter and has held world records in more than one discipline conducted extensive testing to determine if weighing cases was a valid method for determining volume using Lapua brass for his 6mm PPC and found that it was not.
My testing involved the use of Lapua brass made by Norma (300 win) and it confirmed this conclusion. You are right in that it is a time consuming and tedious process. If it makes you feel better and gives you more confidence at the line then by all means go ahead and do it.
I agree with JE Custom in principle. I recently however ran calculations using Quickload to measure the effects of a 1 grain weight difference. The concept is that cartridge brass has a specific gravity of 8.56 compared to water with a specific gravity of 1.0. Therefore a case with 1 grain less brass increases the case capacity by 0.117 grains of H20. .
My calcuation assumed a 300 Win Mag shooting 190 grain Bergers at 1000 yards. I assumed SAAMI seating depth and 75 grains of VV-N560 powder ( a load I use) with a 24" barrel. The increase in case volume (in this example from 93.0 to 93.117 grains reduces the camber pressure and in this calculation dropped the velocity from 2959 to 2957 ftps. The calculated drop at 1000 yards (standard metro and sea level) changed from 311.7 inches to 312.2 inches. A difference of 0.5 inches.
Is a half inch at 1000 yards important? It could be the difference between winning or loosing a 1000 yard benchrest match. It could matter if you're shooting prairie dogs.
I also checked the effect of a 1 grain change in propellant weight. Going from 75 to 76 grains changed the velocity from 2957 fps to 2999 fps, a difference of 40 fps which changes the drop at 1000 yards by 9.5 inches. I think any long range hunter would agree that's significant.
Can brass weight vary without a proportional change in case volume? Yes. When brass is fired the case walls and neck conform to the chamber dimensions, but differences in the case head diameter or the volume of the extractor groove are not reflected in the interior chamber volume. If the weight difference is in the neck it can have other other effect which affect velocity and accuracy.
Neither sorting for weight uniformity or volume uniformity is a guarantee that the walls and necks are symmetrical.
For it to make sense to sort brass to 1 grain it should be obvious that one must also measure charge weights to 0.05 grains or better to make weighing cases have more effect than charge weight. I do both. My powder scale resolves .02 grains and I weigh each charge to +/- .02 grains. To get better uniformity of the case head diameter and extractor grooves I don't mix headstamps or manufacturer batches.
Well if that is your opinion then you are certainly entitled to it. Just because you do not have the means to accurately measure the internal volume that is a process issue that you must resolve. I myself was skeptical of this at first because I wanted an easy way to measure the interior volume of cases. My smith who is a HOF Shooter and has held world records in more than one discipline conducted extensive testing to determine if weighing cases was a valid method for determining volume using Lapua brass for his 6mm PPC and found that it was not.
My testing involved the use of Lapua brass made by Norma (300 win) and it confirmed this conclusion. You are right in that it is a time consuming and tedious process. If it makes you feel better and gives you more confidence at the line then by all means go ahead and do it.