Another Basic Question - Why weigh and sort brass?

[memilanuk]

Steve,

I use mostly Excel 2007... had to learn fast when my 'puter crashed right at the beginning of my stats class and the new one had 2007 on it... somewhat of a change of pace from 2003

I've used R, but sadly still not proficient with it. The others are too rich for my blood

Monte

 

[boogershooter]

I have'nt spent much time weighing cases, so just gonna throw this out there. If water volume is not repeatable, how about the use of something more dense like some # 9 lead shot or another heavy metal??? Or mercury? You guys got my wheels turning. You need something heavier to show a greater variation maybe.

 

[Steve Blair]

I am going to try using some AA 2520 tomorrow. If you have ever used this powder, you will know why. It should be uniform and easy to strike across the case mouth. If it provides repeatable results, it may be a good way to go.

 

[Steve Blair]

What were the group sizes at 300 yards?

Joe,

I did not save the target scans. I used "On Target" to locate the group centers. They were ~1.2 & ~1.4. The rifle shoots in the low .2 range with a good load at 100 yards. It is an 8" twist, 22" Hart barrel. The single-target attachment was shot today with the same rifle, 75g Berger VLDs and 25.1 8208 XBR at 100 yards.

Shooting good 300 yard groups at SBR&GC means getting there at 8am and getting it done quickly. By 10am, it is usually gusty to windy and tough to judge the crosswinds. Because of the slope and high berms, you can only see one flag through the scope.

Today was a good example. I was shooting a McGowen-barreled Savage 12F .308. at 300 yards. 30" bull barrel, complete SSS tune with Evolution trigger and Nightforce 12-42BR from a Farley rest and Edgewood Minigater rear bag. The load was 44.0 8208 XBR in Lapua brass, CCI-BR2 and Lapua 155 Scenars. This is a very accurate rifle and load, shot from a good rest. But, today was windy. The multi-target attached image is one of the targets. These are 600 yard MR-63F centers reduced for 300 yards that I made. I shot target 1 in a gusty headwind and put on 3 clicks right. The wind started switching quickly while I was shooting target 2. The edge shot is actually from the next target paper. I shot target 4 and was getting frustrated and decided to shoot one aiming point to see what was really happening instead of chasing the conditions. I shot target 3 holding center for all five shots. You can see what the wind was doing at that point, it was switching right to left. The vertical was very good and indicative of what the rig and load can do. The horizontal leaves room for improvement.

When we have wind from the south (behind the firing line), it hits the 200 yard berm and blows the bullet up as much as 2" at 300. When it comes from the north, it comes down the slope and can push it down as much as 1". The range is in rough terrain and the Mexican border is just a couple miles south. Here is a link to Google maps so you can see the site.

http://www.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=South+Bay+Rod+%26+Gun+Club,+1020+Marron+Valley+Road,+Dulzura,+CA+91917&sll=32.988446,-117.093329&sspn=0.015299,0.016222&ie=UTF8&hq=South+Bay+Rod+%26+Gun+Club,&hnear=1020+Marron+Valley+Rd,+Dulzura,+CA+91917&ll=32.607974,-116.771836&spn=0.007682,0.008111&t=h&z=17

Sorry for the long reply.

 

[Ackman]

[quote author=Ackman] I've posted about this several times.

I am not trying to provoke you, but posting does not constitute evidence. I asked whether you have anything to validate what you say. ?
[/quote]

There's more bs in the shooting world than anyplace I can think of. And people just love to get buried with data and make things more complicated than they need to be.

Gator you need to understand something. I don't have to prove anything. Believe me or not it doesn't matter, makes no difference and doesn't change anything. That afternoon spent with .223 brass was done to satisfy my own curiosity, not for people on an internet forum. The sheet of results is around somewhere and will turn up, but I'm not gonna spend time looking for it. Benchresters are the fussiest, pickiest, most anal shooters anywhere and even they don't agree about weight sorting. Believe what you want about any of this stuff.....whatever floats your boat.

 

[Steve Blair]

That's what I thought.

 

[Ackman]

That's what I thought.

Listen jerk, don't go there. Don't you or anyone else say I'm making things up. It's been a few years and I've posted on this with numbers.

 

[Steve Blair]

Sir,

I said no such thing and your defensiveness is a little hard to understand. This forum is about sharing knowledge and experience. Even if you had anecdotal experience, that is OK. I was just trying to determine whether you had some basis for your statements. If you had evidence that contradicted mine, I would re-evaluate my methods and conclusions. That is how truth is determined. I am not reluctant to acknowledge when I am proved wrong. If you say that you have evaluated weight sorting previously, I accept that at face value. No one expects you to keep records on a subject you think is closed. But that is all you needed to say. Resorting to name-calling is not helpful.

 

[TonyR]

Using powder to measure volume might be just the thing. I am thinking about Ramshot Magnum which is made up of tiny little balls and is about as compressable as concrete. I worked up a ladder in QuickLoad for my 284 Shehane and once the base of the boat-tail came in contact with the powder, that was it for seating depth. i shoot compressed loads occasionaily with other powders, but i've never experienced anything like this before.

 

[Steve Blair]

That was my thinking, Tony. AA 2520 is the same. It looks like very small, uniform, black ball bearings. As soon as I finish the taxes I will try measuring the same case 20 times and see what repeatability is possible.

 

[Ackman]

This forum is about sharing knowledge and experience. Even if you had anecdotal experience, that is OK. I was just trying to determine whether you had some basis for your statements.

Ok let's get something straight. I'll post about things if I've done them. There's no "anecdotal". I don't repeat as fact things from some board or magazine article, or "heard," or assumed. I'll mention what someone else has done only if I've seen them do it, or know the person well enough to vouch that they absolutely know what they're talking about and what they tell me is absolute fact.

 

[Steve Blair]

Ackman,
"Anecdotal" does not mean secondhand or fabricated. Please note definition 2. I was not impugning your veracity, honor, methods or approach. Anecdotal experience, absent scientific method, can still provide valuable information. If something works, but the users do not know why or have not investigated, it still works.

an·ec·dot·al adj.
1. also an·ec·dot·ic or an·ec·dot·i·cal Of, characterized by, or full of anecdotes.
2. Based on casual observations or indications rather than rigorous or scientific analysis.

 

[Ackman]

And it also means based not on facts or research therefore not reliable. Let's cut this crap. I measured case volume of lightest and heaviest cases and in between. There was no correlation between volume and weight. One headstamp the heaviest also held the most. The other headstamp, second heaviest held the most. With both, the lightest case didn't hold second most. One headstamp had at least 2 times the weight variation heaviest-lightest of the other but only 1/3 the volume variation. That's the way it was and it's not anecdotal. If you don't agree, then don't. But just cut the crap.

 

[TonyR]

Ackman.
Does your last post describe comparisons of cases for the same cartridge but from different manufacturers ("headstamp")? I have never done that comparison and it would be interesting to know what might happen. Most of the articles I've read about case prep talk about keeping cases from the same lot or at least brand together and your results would certainly illustrate why, , if that is what you did test. The only testing I've done has been with cases from the same lot fired the same number of times since annealing.

 

[Steve Blair]

There is no crap. You are wrong on the definition of anecdotal. It just means not scientifically or rigorously derived. If I told you that I shot a .234" group Friday and showed you the target, that is anecdotal. It is a fact and, if you believe I shot it, is reliable. It just may not have a sound scientific or statistical basis.

The problem here is that you are saying that your experience applies universally and there can be no other conclusion. All I said was that this was my experience, how it was derived, the sample size and my conclusion. If you have a problem with my method or conclusion, tell me how you think I erred. I will read what you have to say and consider it. I have no reason to doubt what you say about your results. It is entirely possible that both our results stem from insufficient sample population size. A reasonable discussion of that might produce some new insight.

 

[BoydAllen]

If you touch a piece of red hot steel and burn your hand and then, for the rest of your life avoid doing so, you have made a decision based on anecdotal information. Most of what we know is anecdotal information. That does not mean that it is less reliable, just that it is not the result of a scientifically conducted study. What irritates me the most, when I share some little bit of experience, is when some jackass asks "what's your reference" as if its appearing in print somehow bestows superior authority. Give me a break. The other thing that gets my goat is when someone acts as if there should automatically be some study or written authority to base every decision on. This is the same guy who invariably spouts statistic speak. Studies have their place, as do statistics, but they are not always useful when dealing with an individual situation, being more useful for making decisions that have broader application, but they can lead you astray when dealing with an individual case. There is no substitute for acute observation of what is in front of you.

 

[Steve Blair]

Boyd gave a better anecdotal example than I did and is exactly right. There are however, some things that must be measured to know.

The early nickle-steel Springfield receivers had highly variable heat treatment and some were brittle, resulting in a small number of failures. It was determined that ordnance workers judged the receiver temperature by eye, based on how brightly it glowed red. General Hatcher's investigation determined that receivers were overheated on bright, sunny days and underheated on dark, cloudy days. Pyrometers were subsequently introduced so that all receivers were heated to approximately the same temperature, regardless of ambient light.

 

[Steve Blair]

Tony,
It looks like AA2520 is a non-starter, at least for me. The first five .308 cases filled from a 4" drop tube and struck level were:
232.76
234.94
233.48
234.22
234.68
That is >2 grains difference. I can get to .1 grain water using a light to judge the meniscus concavity/convexity and adjusting.

 

[TonyR]

Thanks for the update, Steve. That is similar to the variation I was getting with the burette. It is amazing what a small drop of water weighs when you can measure to 0.02gr. I have tried controling the meniscus by adding 25% alchohol to the water and adjusting for the change in density. The densities of various mixtures are on the web. But I have been thinking about something like the mirror some mechanical balances use behind the index marks to insure a constant meniscus. I think if I was shooting 1000 yard benchrest I would spend more time on this, but I have found that weight sorting large numbers of cases from the same lot into very tight weight groups, along with a bunch of other tedious boring things, is giving me execellent vertical on the F-Class targets. I would be very interested in anything you come up with.

 

[wapiti25]

I like the work that sleepygator has done and documented. I have one comment that I think comes into play on the volumne issue. New cases are not sized absolutly the same form the mfg., once fired cases (same lot) with the same load (pressure) fired in the same chamber would give the best chance to measure volumne. The brass work hardning/ spring back comes into play. Thank you for the good work that you have done.