April 23, 2017, 07:57 PM | #1 |
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Sorting Bullets
What tolerance for weight variation do y'all allow for match loads? Bryan Litz says that sorting by weight isn't that useful with most quality match bullets since the tolerances are so close. I have verified 3 full boxes of a lot of 1k Hornady ELD 225 gr bullets I have, the extreme spread is .4 gr, or 0.0017 (17/100ths of 1%). My software says, all else equal, it takes 3.0 full gr to change my barrel time by 0.02 ms, which changes my POI at 1k yards by 3 inches.
Now, to hold POI the same, accounting for the difference in velocity, pressure, and flight which occurs with the difference weight, it takes 1 gr difference in Bullet weight, all else equal to move POI 1" at 1,000 yards. At 11/10 of a gr in this case my barrel time doesn't change enough to register a difference. (Note this is for a 225 gr bullet, I'm sure 1 grain makes a much bigger difference on a 77 gr match king at long range) I guess I'm posing a suggestive question since their is technically a difference between POI at 1k, albeit slight. One thing Litz suggests is sorting by bullet base to ogive, I'm sure he knows what he is talking about and the software backs it up, a change of just 2/1000 will change poi more than 1" at 1k yards. I'm just not sure dividing and sub dividing helps unless you are shooting true 1k international benchrest where 10/100 of 1" can be the difference between 1st and off the leaderboards. I know in the end that it is a lot of little things that add up, but I wonder if there are other things to focus heavily on and others that really just won't make any difference. Last edited by Stats Shooter; April 23, 2017 at 08:05 PM. |
April 23, 2017, 08:44 PM | #2 |
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If you're going to sort by weight, you'll need to do an accuracy and R&R study on your scale. I'm surprised you're getting that much variation in weight.
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April 23, 2017, 09:04 PM | #3 | |
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April 24, 2017, 08:23 AM | #4 | |
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April 24, 2017, 08:30 AM | #5 | |
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Which means, bottom line, no need to sort. However, I still think weight checking can be useful if for no other reason than catch the one or two oddballs that are well outside the normal boundaries. I.e. in this case a bullet that is a full gr heavier than average and use that bullet for barrel fouling shots |
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April 24, 2017, 08:56 AM | #6 |
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I weighted bullet's years ago. Sierra Match Kings. Boy was that a waste of time. I weighted some old Herter bullet's once too. They were all over the board. I quit and just shot them up. Probably should have melted them for the lead!
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April 24, 2017, 10:38 AM | #7 |
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Mississippi, here's a little "experiment" you can try to see if your scale is repeatable. Take ten bullets and number them (you don't need to actually put numbers on them, sit them on a piece of paper with the paper marked as to which bullet is which). Weigh them from 1 thru 10 and again do it 10-1. After that, weigh them at random and see if you get the same number each time. Make sure the scale is warmed up before starting. This will tell you whether or not the scale is repeatable. Repeatable is good, but it doesn't tell you if it's accurate or not. You'd need check weights to measure accuracy. However, for shooting purposes accuracy isn't as important as repeatability. Let us know what you get.
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April 24, 2017, 11:19 AM | #8 |
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This is Bryan Litz or sorting bullets
Bryan recommended sorting by “Base to Ogive”. Litz noted that: “Sorting by overall length can be misleading because of the nature of the open-tip match bullet. You might get a bullet that measures longer because it has a jagged [tip], but that bullet might not fly any different. But measuring base to ogive might indicate that the bullet is formed differently — basically it’s a higher resolution measurement….” I'm sure he's not posting about Hornady bullets.
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April 24, 2017, 12:13 PM | #9 |
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In regards to my own anal-retentiveness, not competition shooting...
I usually look for less than 1% deviation from average - weighed average, not advertised weight - and try to get below 0.5%. But I don't sort good bullets unless I'm just bored and curious about how they compare to past experience. I typically only weight-sort bulk purchases of 'mid-grade' bullets or seconds/blems. But, even then, it sometimes turns out to have not been necessary. A few years back, I sorted 1,000 6mm 95 gr Hornady SSTs that I bought as "blemished plastic-tipped hunting bullets". It was actually the first time I ever saw a proper bell curve with a single peak. I had always had multiple peaks and humps overlapping, prior to that. (Copied and pasted from an old discussion Average weight 95.1 gr (95.103). Minimum 94.9 gr. Maximum 95.3 gr. Min and max weights only deviate 0.2% from the average. The count: 1,000 total (exactly 1,000 - no extras). 94.9 gr - 26 (2.6%) 95.0 gr - 95 (9.5%) 95.1 gr - 715 (71.5%) 95.2 gr - 151 (15.1%) 95.3 gr - 13 (1.3%) The blem? A boogered cannelure.
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April 24, 2017, 01:33 PM | #10 |
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Yea I only brought this all up because many of these rounds will be fired at 1k yards. Now, the X-ring is 1/2 MOA and the 10 ring is 1 moa. So at 1k yards that is 5"=X and 10"=10. Im already shooting on average, in the "Expert" class which is near 190 in my case....or 570 total. However match winners are shooting 595-600 with X's often being the deciding factor.
I am relatively new to competitive shooting, and I never did much weight sorting simply because I didn't shoot very long range and it takes a relatively big difference in weight to matter at <300 yards....but 1k yards is a different story where 1/2% makes a measurable difference. Not HUGE, but measurable. But there are always trade-offs right? It takes time to prep 75 or so cases for a match, annealing, body sizing, neck sizing, neck turning, trimming, etc etc. And there are things that make a much bigger difference, like consistent bullet hold, consistent case volume, consistent ignition. I am 34 with a full time job, side consulting business, and 2 kids. So Not retired and do not have too much time. I just try and address the things that make the most difference, and try to become a better wind reader/shooter. Now I am fully aware that bughole accuracy is the culmination of a lot of little things. But, if I can eliminate a step and it won't really change things much, then that is a big help. |
April 24, 2017, 06:09 PM | #11 |
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Weighing projectiles
Mississippi:
When I recently started buying bulk bullets, I weighed them out of curiousity. My experience is somewhat limited, but here it is for what it is worth. Hornady 68 gr and 75 gr BTHP Match bullets in .223 Remington were the most consistent weight. I bought a 500 round bulk box of 68 gr from MidwayUSA recently and all of them weighed 68.0-68.1 grs. I bought a 100 round pack of the latter over the counter and all of them weighed 75.0-75.1 grs. I bought a 500 round box of Hornady 55 gr and Hornady 500 round box of 62 gr FMJ also .223 Remington from MidwayUSA. Approximately half of each were 0.1-0.3 grs light and the other half were 0.0-0.4 grs heavier than the stated weight. My experience with .45 ACP is that Missouri and Extreme is about the same: half were 0.1-0.3 grs light and half were 0.0-0.4 grs heavier than the stated weight. Berry's were a little better. I don't know whether sorting and reloading any of these projectiles by weight produced better results, but I feel it eliminated one potential variable. With me, the biggest problem with my groups opening up is the shooter. |
April 24, 2017, 06:23 PM | #12 |
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Wow, we really need to buy you guys a tv...
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April 26, 2017, 09:43 PM | #13 |
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So I went and weight sorted the entire batch of 1000...Recall that they are 225 gr hornady ELD-M. I set a benchmark of extreme spread of approximately 1/4% or 0
5 gr. I also verified my scale with some weights, and by re checking its measurements previously found on some bullets. I said in the OP that the ES was 0.04 but forgot to include "0" (embarrassing ) so it was actually 0.5 on the first 400. On the remaining 500 I found 12 that were below 224.8 and 43 over 225.2, but only by about 0.2 gr. The extreme spread of the whole batch though was 1 gr, or less than 1/2%. So the question is, does it matter? Well, if so maybe I just added a couple points or X's to my score... If not, I just spent 2 unnecessary hours looking at my scale. But at least I'll know that any flyer wasn't because of an off weight bullet. |
April 26, 2017, 10:07 PM | #14 |
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Does it matter?
To me? No. To you? Yes. And now that you know which bullets are at the "extreme" ends of the spectrum, you can cull them and just use them for practice. You did segregate, didn't you? Or... shoot a 50-round group at 500-600 yards, while tracking the bullet weights, and see if you can identify a correlation with POI. (I did such with .220 Swift and a huge lot of 55 gr bullets almost 10 years ago. Turned out to be a waste of time. But... at least I knew that it was a waste of time, and didn't have to wonder any more.)
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April 26, 2017, 10:18 PM | #15 | |
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April 27, 2017, 11:21 AM | #16 |
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To check accuracy of the scale, throw a charge into the pan and trickle it to right on. Now try to set the measure to throw that. Got it? Now throw 10 charge's and weight them. If you were throwing ten gr charges, the load should come out right at 100grs. If it doesn't, it's the powder measure. With a balance beam scale I don't know of one that is guaranteed to better than +/- 1/10th grain. I think I read somewhere that digital's are the same, +/- 1/10th. I measured out a tenth grain of Varget I thing it was, a few days ago and a tenth grain ain't much powder!
BTW, to check the scale use ball or flake powder! Meter's much better! |
April 27, 2017, 12:23 PM | #17 | |
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April 27, 2017, 02:37 PM | #18 |
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I appreciated the suggestions for scale checking, but I was already aware of the different methods.
The first and "best" method is to in fact use certified check weights. Most scales come with one for calibration, but if you really want to see how accurate your scale is to the "True" weight it is reading, a series of check weights will accomplish this. I have several allowing me to go from 20 grains all the way up to 2,000. If you don't have check weights, the next best thing is to do as others on here have suggested and weigh a series of items, brass cases, bullets, etc..keeping track of what the scale said, and then weigh them again. You can also double it up or use other items to check a range of weights. This method will not tell you if your scale is weighing the "true" weight of the item, but it will ensure consistency which in many cases is good enough. I.e. if you scale weighs 0.2 gr too heavy, but it always weighs 0.2gr too heavy then it will work just fine. But I digress, after weighing the bullets, I will be confident that at 1,000 yards, if I throw a flier, it wont be because of inconsistent bullet weight. |
April 27, 2017, 08:07 PM | #19 |
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First you start weighing and sorting bullets by weight. Next you will be sorting a sized headstamp by internal volume...
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April 27, 2017, 11:04 PM | #20 | |
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I don't like to have to count more than 1 hole |
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