The UK's Finest Independent Forum for Shooters and Gun Owners. Est 2010.

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Hi guys

At what point does the bullet reach maximum verlocity?

I imagine it is just before it leaves the barrel?

If the bullet is traveling as fast as it can, then obviously
It will be decelerating the moment it leaves the barrel?

Regards

ozone

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I guess it could start slowing in the barrel if the powder was nearly used and the pressure dropped.

As dogdyrog says, depends when the propellant has been expended! You get muzzle flash when excess powder is burnt as the bullet leaves the barrel. If you get no muzzle flash (and you're not using a muzzle break or flash hider etc) then the powder has most likely already burnt, therefore the bullet may have started slowing down in the barrel.

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Ah right, so the skill is to get the powder to finish burning
about 1mm from the end of the barrel and therefore the
pressure will be increasing right up to the end but not wasting
any excess powder by flashing out the end?

ozone

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Yes, but that skill is left to the scientists/engineers when formulating powder. We as handloads already know to use suitable powders for a certain calibre.

The aim is to make accurate ammo, makes no difference to me if there's no flash or quite a lot. Obviously one does not try to waste excess powder unnecessarily. I have a chronograph and so far I have not gone beyond the point of diminished returns whereby velocity no longer increases at the same linear rate as powder charge.

I'm hoping Laurie will come along and give a good discussion on this topic, I'm sure he can word my response a lot better with some corrections if necessary!

WelshShooter wrote:
I'm hoping Laurie will come along and give a good discussion on this topic, I'm sure he can word my response a lot better with some corrections if necessary!

Explanation was spot on, I understood you so it must have been good :-)
I find the subject very interesting and the skills of people involved are high.

Thank you

ozone

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I have no physics based learning on the subject but I'd be inclined to think that the bullet continued to accelerate just as it left the barrel still with gas pressure behind it but suddenly free of the friction between bullet and barrel.