Eric Stecker
Well-Known Member
- Joined
- Jul 27, 2007
- Messages
- 292
Dave,
The effect of weight variation on performance is a commonly misunderstood concept and rightfully so. It is reasonable to believe that if everything were precisely the same that performance will be as optimized as is possible. Although this seems reasonable it is rather true that certain characteristics can vary and produce little to no negative influence on performance.
You don't need to take my word for it as the test for this is simple and will give you a clear result. If you (or anyone) are interested in testing this situation it takes 60 shots to produce a clear result. You can use fewer shots but the fewer you use the less certain you'll be of the results.
I recommend that you read all the information below before you start sorting. You'll be working to gather bullets into the four following groups:
The first group consists of bullets that are exactly the same weight as each other and are the average weight of the population. Example: When you weigh the bullets and find that they run from 174.9 grains to 175.4 grains, you want bullets that weigh the average or 175.2 grains. You need 20 each.
The second group consists of bullets that are exactly the same weight as each other and are the lightest that you find in the bullets you sorted. Since the number of bullets at the extreme edges of the population will be smaller you can use bullets that are more plentiful but not quite on the edge of the weight you find when you sort them. Example: Even though you found a bullet that weighs 174.7 grains it may be the only one so don't use this as your lightest weight group but rather use 174.9 grain bullets of which there are more available. You need 20 each.
The third group consists of bullets that are exactly the same weight as each other and are the heaviest that you find in the bullets you sorted. The same situation that applied to the light group applies to this group. Use a weight that is the heaviest and has enough bullets in it to conduct this test. You need 20 each.
The fourth group consists of 5 bullets from each of the other three groups. After you have gathered together 20 bullets each of the other three groups, take five bullets from each of these three groups and blend these bullets together to make up the fourth group of bullets.
At this point you will have four groups of 15 bullets each. Three of these groups have bullets that are exactly the same weight but each group represents the lightest, average and heaviest weights of the bullets you sorted. The other group is a mixture of all three groups. It is important that you blend the bullets in the fourth group together so that you don't know which 5 are light, average or heavy.
The most important part of this test is that you are very careful to keep the groups separated and clearly identified. This is the only way to ensure that you will trust the results.
Load ammo using the four groups of bullets keeping them separated and clearly marked. All the ammo using all four groups of bullets needs to be loaded the same way, using the same components. When you've finished loading the ammo it is time to go to the range.
There are a few different ways you can fire the groups for this test. The first is to simply rotate between the groups and shoot at separate target bulls. In this test you want to shoot each of the four weight groups by shooting 5 separate groups that are 3 shots each (15 shots). You will end up with 20 bulls, each of which will have one 3 shot group. It is best if you rotate between the four weight groups as you shoot to even out the effects of changing wind conditions on your results.
NOTE: 3 shot groups are better for testing equipment and load than 5 shot groups. I was taught by a prominent short range BR Champion that "3 shots tests the equipment, 5 shots tests the shooter". I've found this to be true in my own shooting and testing.
An alternative way to shoot the groups involves covering the tips of the bullets with different colored marker ink. This allows you to mix the ammo and shoot the bullets of the different groups at the same time and into the same target bull. The ink on the tips of the bullets will allow you to identify which group each shot was from. Frankly, I believe this is the better testing method since no weight group gets the advantage of a brief let up or stabilization of the wind. By color marking the bullets you can shoot one 12 shot group on one bull which will consist of 3 shots from each weight group.
I recommend that you mark up a few and try them first to make sure you are transferring the color to the target effectively. It will be a bummer to put dozens of shots downrange and then learn that you didn't get the ink transferring to the target properly. Keep in mind that you shouldn't shoot all 60 shots into one target bull but using this method you can shoot 12 shots into one bull. Also, shooting at longer range will make it easier to identify the color of individual shots if you use this method.
I will make the prediction that all the bullets will group in generally the same area. There will be no discernable and consistent increased performance that can be clearly identified as existing within any of the four weight groups. In fact the fourth group will shoot as well as the other three even though these bullets are of mixed weight. It will also be observed that the groups end up in the same general location on the target. In other words, you won't find that the lightest group prints higher (or lower depending on how far you shoot) when the difference in weight between the bullets is this small.
The truth is that weight differences at this level (+/- 0.3 grains in bullets 150 grains or heavier) have very little if any influence on flight performance. Factors such as drag, balance around the axis and dimensional consistency influence performance to a much greater degree than the actual weight of the bullet. In the end you can be confident that bullets that fall within our tolerances will perform as expected. Having said this, I still believe that sorting is not a waste of time. I'm not saying that you need to break the bullets up into very tight weight groups but rather I suggest sorting to ensure that you don't have an anomalous bullet that falls far outside the tolerance which can effect performance. We work hard to keep tight weight tolerance control but to say that an odd weight bullet does not get through from time to time is not realistic or the truth.
I realize this is a long response to your post but this is something that comes up often so I wanted to take this opportunity to expand on this subject for the sake of others who are reading this thread and who aren't aware of this situation.
Regards,
Eric
Hope you are doing well.
