Weight sorted brass and ES

E

Eric K

Guest
Ok, I now have 500 pieces of 6.5x47l Lapua brass weight sorted to .1 grains. I will test 5 pieces of brass at the low, middle, and high end of the weight scale. This should be an interesting test. With any luck I will post the results after the weekend.

Eric
 
only if the sort was done after full prep.
case length adds wieght, but not volume( as bullets are seated the same).
primer pocket truing removes weight but no internal volume change,as the primers are seated to bottom of the pocket.
debur the inside of the primer fire hole removes wieght and adds volume.
neck turning removes wieght but not volume .....

oh and did you do the same with the bullets...sorted ??

and how is the powder measured ?? a beam scale ruins the test....
need a lab scale at 0.0x sensitivity.....

make it a valid test....
can't just control one component and claim a valid test.

mike in co
 
Last edited by a moderator:
Mike agreed re: all the variables. But how does a beam scale invalidate a test ?
 
Eric K said:
Ok, I now have 500 pieces of 6.5x47l Lapua brass weight sorted to .1 grains. I will test 5 pieces of brass at the low, middle, and high end of the weight scale. This should be an interesting test. With any luck I will post the results after the weekend.

Eric
Click to expand...

You GO Eric!!! THIS is how it's done..... test stuff and find out if it matters.

good for you

al
 
It would be grand if weighing brass was that simple. Some years ago when I tested things like that, I had on hand
a new box of Lapua ppc cases. Nearly 20 % was 2 plus grains higher than the rest. Checking the extractor grooves
with a blade micrometer, it was clear something changed in a secondary operation. Chrono readings all good and no
different than the rest.
 
it aint accurate enough to cover the small volume differences involved in the cases.
the beam scale is plus or minus .1 on a good day..and most days are not good.
plus or minus 0.1 means your powder will be :example...45.5 as an ideal and the spread 45.4 to 45.6.....that much powder change will hide small volume diff of the cases....
mike in co

Flouncer said:
Mike agreed re: all the variables. But how does a beam scale invalidate a test ?
Click to expand...
 
before loading the brass, check the volume.
install old primers inverted, weigh, fill with aprox 77degree water and re wiegh,,,the diff is vol .
if no discernable vol diff don't bother the load test.

when all brass is from a single lot, when the wieght is different..the exterior is the same( or see the post above) then the vol will be different...is it enought to affect..accuracy, i don't know..i don't have enough experience, but my single test says it does...( 500 pc one lot, had one lot of 30 pcs that wieghed the same AND had the same volume).
mike in co
 
Hi Mike,

I thought about the brass prep, but I will not trim to length until after the case has been fireformed at least once. Lets look at volume from my point of view. A lighter case should have more volume than the heavier one. Once the brass has been fireformed the volume will remain uniform per weighed case in the same grouping. I use a Sartorius/MX123 scale to check my final powder weight. I don't have a full blown lab grade scale, but this scale can discern a change in weight with just one kernal of H4350. Bullets are sorted by weight and bearing surface length. The only variable in the test should be case weight.

Eric

Lapua Brass from same lot

Brass Weight by grain total pc's
158.7 1
158.8 16 test
158.9 31
159.0 35
159.1 81
159.2 78
159.3 84 test
159.4 71
159.5 55
159.6 29
159.7 8 test
159.8 3
159.9 2
160.0 6
 
mike in co said:
it aint accurate enough to cover the small volume differences involved in the cases.
the beam scale is plus or minus .1 on a good day..and most days are not good.
plus or minus 0.1 means your powder will be :example...45.5 as an ideal and the spread 45.4 to 45.6.....that much powder change will hide small volume diff of the cases....
mike in co
Click to expand...

JMHO, but drift is a problem with electronic scales, a big one with the cheaper scales. With beam balances, gravity is a constant. I use analytical electronic balances in the lab & even they need re-zeroing before a measurement.

With either type, the measurements are +\- something. I do not prefer electronic reloading scales for the same reason I do not like electronic test indicators for truing work in the lathe.

Regards, Ron
 
Brass weight

I weighed a box of Lapua brass once and it was all within +/- 1 grain. I weighed some WCC 04 brass and that had a range of over 15 grains; that I sorted in .5 grain groups after I prepped it and it shoots very well. Brass is 8X as dense as water so before you'd see .1 grains difference in water volume you'd have .8 grains difference in weight. - nhk
 
which is why i said full prep first and the powder must be wieghed on something other than a beam scale...sorry i should have said on a lab scale.
mike in co

nhkuehl said:
I weighed a box of Lapua brass once and it was all within +/- 1 grain. I weighed some WCC 04 brass and that had a range of over 15 grains; that I sorted in .5 grain groups after I prepped it and it shoots very well. Brass is 8X as dense as water so before you'd see .1 grains difference in water volume you'd have .8 grains difference in weight. - nhk
Click to expand...
 
yes i should have qualified the statement..a quality lab type scale...the mx123 or something close.
gravity maybe constant but so is dust...pivot point changes...go read the beam scale threads....
mike in co

RJM said:
JMHO, but drift is a problem with electronic scales, a big one with the cheaper scales. With beam balances, gravity is a constant. I use analytical electronic balances in the lab & even they need re-zeroing before a measurement.

With either type, the measurements are +\- something. I do not prefer electronic reloading scales for the same reason I do not like electronic test indicators for truing work in the lathe.

Regards, Ron
Click to expand...
 
i would love to see the results, but it really has to be a controlled test where the volume/wieght difference is the only variable.
this has gone on for years with no real test data.
5-6 years back a guy made a statement on 223 brass that sorting was a waste..."cause he did it and it was a waste"....what he did was wieght sort 500 pcs of 223 brass and volume check from each end. he cliamed no big difference. the problem was it was MIXED RANGE BRASS...not from one lot....a complete waste of time.

good luck with the test

mike in co
 
Hi all

I read the Accurate Shooter Daily Bulletin article last Friday about the Sartorius GD503 analytical balance. It costs twice as much as the iBalance 211 I recently bought, but they both have the glass box around the scale with sliding doors for access that are essential in a precision electronic balance to minimise the effect of air movement.

I bought the upgraded RCBS powder trickler-2 to suit the electronic balance but then ordered the Omega 2-speed electric powder trickler I saw mentioned in the Sartorius GD503 review. Trickling single kernels means good bye forceps! Interestingly, Dandy Reloading Tools also sell the Handy View to view the tip of a beam scale more easily (an RCBS 10-10, no less).

Even with my new balance I still maintain that a good beam balance like an Ohaus/RCBS 10-10 is hard to beat. Then again I haven't posted 5 times already in this thread so I might lack credibility. ;-)

I weight sort prepped and fire formed brass but I don't bother with measuring the internal volume. Don't forget that the volume of the combustion chamber that imparts energy by burning powder and hence velocity to the bullet includes the volume of the barrel. Except with extremely overbore cartridges small differences in cartridge volume make very little difference to the expansion ratio.

Regards
Ben
 
I had a world champ BR shooter tell me one time that after he gets his Harrells set, how many clicks hes gonna shoot that day, he dont even weigh the charge again with vv 133. My Harrells will vary a .1. Theres other factors thatll mess with you more.
 
Weighing vs. dumping powder

It's long been a practice of benchrest shooters to dump charges. +/- .1 grain at 100-200 yards isn't going to have much effect on vertical. Long range shooters mostly weigh charges. I'll dump ball powder, but weigh extruded powder. A granule of Varget weighs about .03 grains so my extruded charges are +/- .03 grains to the best of my ability. My long range loads have an SD of 9 fps or less and the velociy has peaked so there is very little vertical. - nhk
 
powder throwers are very dependent on your technique and the powder being thrown.
oem 8208 throws around plus or minus .05...
imr 8208 throws around plus or minus .09
n133 throws around plus or minus .2 with excursions to .3

when you have done a 100 throws onto a lab scale....come back and tell me how great your thrower is.
i have done all three powders listed.
i dont know if plus or minus 9.1 will effect at 100/200...but prove to me you do plus or minus 0.1.....no beam scale readings...just a waste of time.
n133 is not plus or minus .1 in a harrells....

mike in co
 
Mike, I wasnt tellin ya how great my Harrells was. I was tryin to say a .1 dont effect your group at 100 yds. much using 133. I weigh every charge with extruded too.That Harrells dont throw it any better than any of my other measures.
 
and what i was saying is that THROWN CHARGES OF N133 ARE NOT PLUS OR MINUS 0.1
mike in co
Doug Casner said:
Mike, I wasnt tellin ya how great my Harrells was. I was tryin to say a .1 dont effect your group at 100 yds. much using 133. I weigh every charge with extruded too.That Harrells dont throw it any better than any of my other measures.
Click to expand...
 
You must log in or register to reply here.
Back
Top