Explain something to me

[74A95]

Try a different browser. It did not show figures/tables in Chrome, but it did in Firefox.

I was saying that IF you shoot a lighter bullet over the same powder charge used for a heavier bullet the lighter bullet will go faster than the heavier bullet does.

The table 2 shows the opposite result.

[74A95]

Hey, I got it to work!




Figure is from: https://www.shootingtimes.com/editor...ves-edge/99399

[44 AMP]

Alright, thank you. I don't understand why that table goes against decades of information I have, so there is clearly something about how they got that data I do not understand.

I looked through Lyman, Hornady, Speer and other reloading books and a dozen or so different cartridges in each, and all had the same pattern, which is 100% the opposite of that shooting times table you were kind enough to show me.

Where the difference in bullet weight was very small (like 50 vs 55gr in .22 cal) using identical charge weights of powder the velocity was essentially the same. Where the difference was a larger percentage (say 40 vs 55gr), the lighter bullet was faster, though I did find a couple of examples where the bullet weight difference was 20% and delivered the same velocity. I looked at rifle and pistol rounds ranging from .22 to .45 caliber and in no case was the lighter bullet ever slower than than the heavier one, over the same charge of powder.

Might you have any idea why that table showed the exact opposite of over 50 years worth of printed data from numerous independent sources??

I have seen many strange things happen with guns and ammo velocities, unexpected differences and even complete overturning the established norms, but every one of those has been the result of something unique to the firearm or ammo being tested, and not something generally applicable overall.

For example, I've seen a 4 inch revolver turn in a higher speed (barely, 15fps than an 8 inch firing the same ammo, but that was the result of a particularly "fast" barrel in the 4 inch and a spectacularly slow one in the 8 in gun.

I've seen different guns with "identical" barrel lengths turn in as much as 100fps difference shooting the same ammo. Not common, but I've seen it.

I'm not disputing what they got, but absent a lot more information, I cannot understand how it happened, and I do not consider it applicable in general.

Ok, I guess I could look at it as "the exception proves the rule" but IF, generally speaking a lighter bullet moves slower than a heavier one, over exactly the same type and amount of powder, why is this not common knowledge and widely known?

Thank you for the table showing the data, but I remain unconvinced it is a general result, and not a unique "one time" thing.

[74A95]

It might be an exception to the rule. I don't know. But you're right, when I look through manuals it shows the lighter bullet going faster or as fast as the heavier one with the same powder charge, at least for the stuff I looked at. Chalk it up to 'life is full of mysteries'.

[Unclenick]

I suspect it has to do with the powder choice, with slower powder needing more inertial resistance from the bullet to provide enough confinement to light up promptly and burn thoroughly. Folks playing with very light-for-caliber bullets or with light bullets in sabots find these bullets can scoot down the barrel so fast the powders they usually use can't maintain their burn well, so they wind up with disappointing muzzle energies and a lot of unburned powder on the ground in front of them. Going to faster powders corrects for that.