NewportNewsMike
Single-Sixer
The following applies to handgun bullets of varying weights and their differing point-of-impacts (POI).
Like many folks on this Forum, I have observed that, from the same gun, using the same point-of-aim (POA), lighter weight bullets will have a lower POI than their heavier weight cousins. Sometimes, depending on weight difference, a large variation of POI – on the order of multiple inches at a range of 15 to 25 yards. This effect is very observable, and very repeatable (does it every time).
Because I had no contrary evidence and it sounds very plausible, I have always accepted the explanation from many different sources that this phenomenon is the result of the presumably faster light weight projectile spending less time in the barrel which is rising from recoil when fired. Less time means earlier exit from the muzzle (which would be at a lower rotational position), and thus the bullet is given less "arc" on its way to the target, resulting in a lower POI.
Until now –
We are into the fourth season of "Top Shot" which is a television show aired on the History Channel. One of "Top Shots" treats is their outstanding high-speed photography. They have amazing footage of bullets in flight, bullets hitting targets, targets exploding / shattering, and bullets leaving the muzzle – all in glorious slow motion splendor.
This high-speed photography showing bullets leaving the muzzle is what this post is all about. In all the various guns shown – semi-automatic pistols, single-action revolvers, double-action revolvers – the bullet is well away (an inch or more) from the muzzle before the gun starts its recoil rotation / movement. This shows that barrel rotation / elevation caused by gun recoil cannot be having any effect on the flight path of the bullet. The bullet is well out of the barrel before there is any barrel or shooter's arm movement.
This seems to be in direct opposition to the well-publicized and accepted theory above on why lighter bullets have different POI than their heavier cousins.
Has anyone else observed this on the high-speed photography?
Any other thoughts or theories about what is happening here to cause differing POI's?
Like many folks on this Forum, I have observed that, from the same gun, using the same point-of-aim (POA), lighter weight bullets will have a lower POI than their heavier weight cousins. Sometimes, depending on weight difference, a large variation of POI – on the order of multiple inches at a range of 15 to 25 yards. This effect is very observable, and very repeatable (does it every time).
Because I had no contrary evidence and it sounds very plausible, I have always accepted the explanation from many different sources that this phenomenon is the result of the presumably faster light weight projectile spending less time in the barrel which is rising from recoil when fired. Less time means earlier exit from the muzzle (which would be at a lower rotational position), and thus the bullet is given less "arc" on its way to the target, resulting in a lower POI.
Until now –
We are into the fourth season of "Top Shot" which is a television show aired on the History Channel. One of "Top Shots" treats is their outstanding high-speed photography. They have amazing footage of bullets in flight, bullets hitting targets, targets exploding / shattering, and bullets leaving the muzzle – all in glorious slow motion splendor.
This high-speed photography showing bullets leaving the muzzle is what this post is all about. In all the various guns shown – semi-automatic pistols, single-action revolvers, double-action revolvers – the bullet is well away (an inch or more) from the muzzle before the gun starts its recoil rotation / movement. This shows that barrel rotation / elevation caused by gun recoil cannot be having any effect on the flight path of the bullet. The bullet is well out of the barrel before there is any barrel or shooter's arm movement.
This seems to be in direct opposition to the well-publicized and accepted theory above on why lighter bullets have different POI than their heavier cousins.
Has anyone else observed this on the high-speed photography?
Any other thoughts or theories about what is happening here to cause differing POI's?
