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Although some people claim the bearing surface of a bullet (the sides of the bullet that touch the rifling as it travels down the barrel) has more impact on a bullets flight, variations in weight also have an impact although the degree of impact is up for debate. We can all agree that a 35gr bullet would fly much differently than a 80gr bullet shot out of the same rifle. But is does a 54.8gr bullet fly noticeably different than a 55.3gr bullet?
Regardless of whether there is a measureable difference based strictly on bullet weight, I believe the weight of the bullet is strongly correlated to the bearing surface. To illustrate lets look at an extreme example: We have 2 bullets of the same caliber and type. Bullet A has a measured bearing surface of 0.4″, and Bullet B has a measured bearing surface of 0.5″. If they are the same caliber and type, that means they are the same material and presumably have very similar densities. If that is true, and the bearing surface is that different you would have to expect there to be a proportional difference in the weight of the two bullets. My theory is just that the inverse of that is also true, meaning a difference in weight likely indicates a proportional difference in bearing surface … or at they are at least correlated.
Like most things in handloading … the more uniform one round is to the next, the more uniform ballistics you can expect. So I weight sort my bullets, and for my match grade ammo I only load bullets that have exactly the same weight (down to 0.1gr). Here is some of the data I collected regarding the weight variance/distribution from a 250 count box of Hornady 22 Cal (.224) 55gr V-MAX Bullets. It essentially indicates the level of quality control and uniformity you can expect from Hornady’s V-MAX bullets.
Bullet: Hornady .224 Caliber 55gr V-MAX
Mfr Part #: 22716
Lot #: 2111363 (Purchased Jan 2012)
Here are some of the calculated aggregates from the data:
- Standard Deviation = 0.098 grains
- Extreme Spread = 0.5 grains
- Extreme Spread % = 0.9%(the extreme spread as a percentage of the overall weight)
