Rimfire concentricity,weight and rim thickness

Sorting

Two rounds that are identical in weight are indeed identical..... in weight. The bullet being the largest contributor to the total weight of the cartridge might allow one to draw many conclusions ie the rounds are identical and should shoot to the same point of impact or possibly one has a big void in the bullet and the other has no powder. They weigh the same but are not going to shoot alike. Pietr mentions a lot of work for a small gain. The law of diminishing returns applies here. In a contest that is won by thousandths of an inch the little things count. And then some one proves me wrong sometimes. I have neither the equipment or skill to compete at a competitive level outside my own little circle but I do buy the ammo that my guns perform well with. I have Eley, RWS , Lapua, Fiocchi, and PMC Target 22 on hand. I don't sort any of it because I'm comfortable with it's performance.[/I]
 
Who said anything about two rounds being identical simply because their weights are identical? I'll try this another way. Ignore your thoughts on sorting. You think sorting does work? Fine. You think sorting doesn't work? Fine. You think sorting can work? Fine. You think sorting can't work? Fine. All completely besides the point. Ignore the answer to any of those questions. Ignore the act of sorting and anything it could or could not accomplish. You've never heard of sorting in your life and have no idea what it might be. OK? This is just a simple exercise, and you can resume believing your previous beliefs immediately after taking part in this exercise. But right now, during the exercise, you have no beliefs on the subject because you've never heard of it. Now, on to the exercise. There are only two questions. Answer each one with only a yes or no, nothing more.

1) In the first case we have a 50.8-grain round and a 51.7-grain round. Do you think the chances are very high of these rounds being similar?

2) In the second case we have a 51.3-grain round and another 51.3-grain round. Do you think the chances of these two rounds being similar are higher than the rounds in the first case?
 
My little foray into this venture: I bought a scale, got all set up, ten little trays, brick of Wolf ME, sorted by 0.1grs. took forever to do, very very boring, I thought to myself, what the heck are you doing. Got all done with the brick, I thought, I'm gonna check my work and guess what? Weighed one tray and got new values, what a waste. Then I lumped them into three piles 0.3grs, figured the largest pile would shoot the best, it didn't, what a waste o time. Thanks, Douglas
 
We had this discussion a few years back, weighed and variances were about 1 grain. And what we discovered was the shorter barreled rifles (under 20") shot better groups with the ammo that was closer in weigh i.e. heavy with heavy and light with light. But when shot in a long barrel like Anschutz 690mm (26.7") or a Remington 40X (I think 28") it was not such a difference (but then again much better rifles). As I remember it someone later did the same experiment but considering velocity and choreographed it and the velocity range were larger on a short barrel vs. long. However they were closer on short barrels when weight was similar. Thus I have started buying longer barreled rimfires so I don't have to worry about sorting my bullets. yep lazy.
 
I did some experimenting.Weiging has some influence,as does rim thickness.But the most influence has bullet runout.I sorted the really bad ones(up to 1/10mm and yes it's Eley match)and they shot groups about 5mm bigger as usual.
As posted in the other topic inserting the round fully by hand helps too.
 
Sorted Some Master-M Last Weekend

Weight sorted some Lapua Master-M (X-Lot) this last weekend and here is what I found:

1000 rounds sorted

≈ 20 rounds between 51.65-51.85 grains
≈ 400 rounds 51.6 grains +/- 0.05 grains
≈ 560 rounds 51.5 grains +/- 0.05 grains
≈ 20 rounds between 51.25-51.45 grains

I was able to sort an additional box [of 50] from the lot and easily end up with 1000 rounds between 51.45-51.65 grains.

This was A LOT of work to sort out less than a box worth of outliers and I doubt it will have an impact on my groups (we'll see once it warms up enough to get out to the range) but what else is a snowbound bloak from up North supposed to do with his free time.

RG

3/1/09 - Sorted another 1000 from the lot. Here's the new totals.

≈ 60 rounds between 51.65-51.85 grains
≈ 930 rounds 51.6 grains +/- 0.05 grains
≈ 980 rounds 51.5 grains +/- 0.05 grains
≈ 30 rounds between 51.25-51.45 grains

Now if it ever gets warm enough to do some shootin, we'll see if it makes any difference.
 
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Randy,

Try your two extremes together in four or six shot groups and see if they are worse than the normal.

Concho Bill
 
Do a statistical analysis if you really want to do this correctly. It has been done by others sorting other flavors of ammo. The answer seems to be it does not matter, but a true statistical analysis would really help put a final answer to this question.

Brent
 
You'll just ignore the results if they don't agree with your already made up mind anyway. *shrug* (There are statistically significant results out there already that show it can help, just depends on the ammo in question. It doesn't help with all ammo, but how that translated into "It doesn't work at all, with any ammo, ever!! n00b!!!" on this site is beyond me.)
 
Sadly, yet another opportunity to inject some objectivity is rained upon.

Shorty, I don't have a dog in this fight, so I don't have a preconceived opinion.

If you know of "statistically significant" tests, wherefore art they?

Those that I have seen have shown no effect. That's not my preconceived notion. That's the facts. Are you the one shrugging?

Brent
 
I've seen tests that say it does/can help, and tests that say it doesn't/can't. (Spend some time with google if you want to read about ammo sorting tests. I've no desire to do that searching again.) Even done some testing of my own, and with cheaper ammo (such as Eley Target Rifle) it helped, and with more expensive ammo (such as Eley Match and Tenex) any differences that may be there were so small they got lost in the noise. Like I said, all depends on the ammo you're using to run the tests with. Obviously when weeding out oddballs it is harder to spot the difference when the difference between the majority and the oddballs is smaller, as is usually the case with more expensive ammo. Are you going to notice a .25" difference? Are you going to notice a 0.025" difference?

Whenever the sorting discussion crops up, the people that are against it seem to conveniently forget that part of the reason sorting by things such as rim thickness can be such a waste of time these days is because competitive shooters used to sort by rim thickness in the past. Sorting by rim thickness used to make a big difference. Manufacturers caught wind of the practice, saw a business oppurtunity, and decided to tighten up their manufacturing techniques, giving us closer tolerances in rim thickness straight out of the box today, and charged us more money for the tighter tolerance ammo. The practice itself worked before this change came about. And anyone that debates that is off their rocker. I'm not saying the practice is still relevant today, not in all cases. But the theory behind the practice is solid. The fact that manufacturers took it upon themselves to give us ammo that no longer benefited as much from the practice, by essentially removing the variable for us, doesn't change the fact that the theory is solid. Just means they've done something about the reasons the theory was developed in the first place.
 
In the past on another forum, I have presented statistically data in a number of experiments that showed there was no difference when sorting by weight to anything close to a 95% confidence level. In one experiment, I presented data using Eley Club, Eley Match, Wolf Match Target and Lapua Super Club. The highest confidence level I got was P = .778 that there was a difference. I was accused of not knowing how to perform statistical tests and in the case of the Eley Match, the unsorted actually had slightly smaller groups than the sorted and Shorty accused me of fudging the data because his pre concieved notion was that that could not happen. Since I spent a career of designing, running and evaluating experiments for the semiconductor industry, I thought I knew how to evaluate experiments but Shorty convinced me that I didn't so the data was removed.

As he pointed out, you either believe or you don't and no amount of hard data will change your mind. But let one guy claim "I got better groups sorting ammo X by ....." and some will jump on the band wagon. I guess on cold winter nights, it is better than drinking yourself into a stupor.

Just My honest opinion because I no longer present facts.
 
_Shorty said:
I've seen tests that say it does/can help, and tests that say it doesn't/can't.
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Which is to say that almost certainly most, if not all of these tests did not do statistical evaluation. And there in lies the problem.

Are you going to notice a .25" difference? Are you going to notice a 0.025" difference?
Click to expand...

If that is my objectiven and I design a statistically appropriate test - yes, of course.




Sorting by rim thickness used to make a big difference.
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I do not dispute it. But I live in the present, not the past.


MKnarr understands the issue quite well. And I have a good deal of faith in the results he posted. Hence my initial comment.

Now RandyG has sorted some ammo to test this idea on another make and model, and Bill Winn made a good suggestion of how to set up a comparison. All that is needed is some statistical analyses and perhaps there may begin to be enough consensus to lay this puppy to rest at last. Or maybe their results really will be different. I'll be interested to see them.
 
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If I get bored enough I might just sort the other 3 bricks as well. This will give me many more data points and increase the sample size of the outliers. As Concho Bill suggested, I will group the low and high outliers together and see how they shoot. I will then compare that with those that have a tighter distribution. The problem here is that the VAST majority of this lot is very tight weight wise. I have done this on some Remington Subsonic HP's I was hoping to hunt with. These had an extreme spread of over 5.0 grains. Even though I did not do a statistical analysis on these (sorry Brent) there was no doubt in my mind that the heavier ones that measured the same shot the best.

I understand the "prove it" attitude all to well and do not have a problem with that. I've worked in electronics industry for going on 25 years. I'm currently in the Process Engineering Dept. where I work. I've worked with some very brilliant people over the years. These people (I would call them funny people but that phrase is already taken) have an unbelievable understanding of Physics, Quantum Mechanics, etc.. If they cannot explain something they start going off in directions that you will never be able to get me to buy into (a fourth dimension?). I actually enjoy working with them. They'll come up to me and ask for my help in running a test for them or something. I'll say to them "that will never work" and they get a real perplexed, almost annoyed look on their face. They scoff and tell me to run it anyway. Then when it fails, they ask why it failed. I'll say I don't know and then they walk off muttering something about my mama. Sometimes there is an art to doing something and it cannot be explained. Sh@t happens, and if you can't explain it, oh well move on.

If I had to guess (and I really shouldn't put this out here) I would say the individual who mentioned the possibility of voids in the bullet might be onto something. If the void was in the center of the bullet, there would be little/no change in the impact location. This could explain why some of the most extreme outliers do not drop out. Others could have the void considerably off center and result in a flier. This might also be happening throughout the samples that measure good also. I could imagine that a larger bullet with just the right size void could measure good but still fall out if the void was off center.

Oh well, life goes on. I'll let you know what happens with my test once it gets a little warmer up here. I'll try and be as scientific as I can. If however nothing explainable comes out of it, I'll crack a beer when I get home and get on with my life.

Cheers,
RandyG
 
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MKnarr, you believe your data, but not someone else's data because it disagrees with yours. Even if their data makes a stronger case. Nobody can possibly run a good test besides you, because everyone else is inept. You believe your data is more sound, and so anyone that has data showing something else has to be a fool. Unless I'm mistaken and it was someone else, you even thought the statistics professor who was in on the discussion didn't know anything about statistics. You remind me of Archie Bunker.
 
MKnarr said:
In the past on another forum, I have presented statistically data in a number of experiments that showed there was no difference when sorting by weight to anything close to a 95% confidence level. In one experiment, I presented data using Eley Club, Eley Match, Wolf Match Target and Lapua Super Club. The highest confidence level I got was P = .778 that there was a difference. I was accused of not knowing how to perform statistical tests and in the case of the Eley Match, the unsorted actually had slightly smaller groups than the sorted and Shorty accused me of fudging the data because his pre concieved notion was that that could not happen. Since I spent a career of designing, running and evaluating experiments for the semiconductor industry, I thought I knew how to evaluate experiments but Shorty convinced me that I didn't so the data was removed.

As he pointed out, you either believe or you don't and no amount of hard data will change your mind. But let one guy claim "I got better groups sorting ammo X by ....." and some will jump on the band wagon. I guess on cold winter nights, it is better than drinking yourself into a stupor.

Just My honest opinion because I no longer present facts.
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Hey, if you're going to take your valuable time and effort to do tests then please post it up here. There's always going to be someone that takes issue or gripes but it's a worthy excercise and lots of guys who never post do, in fact, appreciate it. You're providing a community service, keep it up.
 
An interesting topic, but either way you go it's now common to have most shooters who care at least a little about winning will weigh their RF ammo and those who do always shoot better and with the same gear than those who don't bother to weigh their match grade ammo.

It's pretty simple to watch shooters and see what ammo they use and then see their scores after the smoke clears, the stock Eley Match gets the nod, but other cheaper ammo that is weighed does nearly just as good, the problem with the cheaper stuff is the vast difference in weight, and that means an awful lot of plinking rounds are left over.
 
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