Please answer what ought to be a simple question about POI

[chris_]

My brain is fried tonight.

If I took a fixed sight 40SW gun and bored it to 10mm and shot the same 180 gr bullets out of it, only now moving 200-300fps faster, I am assuming my POI is going to go UP and I am going to need a taller front sight, yes?

 

[JHRosier]

Faster bullets leave the barrel sooner in the recoil cycle & will shoot lower.
You move the front sight in the opposite direction that you want to move the POI.
A shorter front sight will be needed.

Jack

 

[2 dogs]

Normally the above is true. Unless you were shooting a much lighter than 180 grain bullet out of your 40. Mostly, you have to go sit down and shoot it on paper. When working on something like that, I take loading tools to the bench so I can sight in the load...

 

[s4s4u]

Shoot it first and see. The faster load will exit earlier, but the faster load should also recoil more which will affect the muzzle rise. Even with the faster velocity, because the muzzle will be a wee bit higher on exit it may come out in the wash. If you use a heavier bullet, it will print higher.

 

[Wyandot Jim]

You Guys need to watch the slow motion in Top Shot.
The bullets look like they are 1-5 feet in front of the muzzle before the muzzle flip :lol: :lol: That was with the Vaquero with light loads and the auto with Std. loads. :wink:
Don't know why or how and don't want to think about it. Will make my weee little brain hurt :roll:

 

[Jimbo357mag]

I have shot the exact same medium weight bullet with three different loads of the same powder in the same gun and each increase in velocity caused a POI higher on the target corresponding to the more recoil higher shooting theory. It might be different for different guns or for lighter bullets but that's my story... :shock: :shock:

 

[s4s4u]

You Guys need to watch the slow motion in Top Shot.
The bullets look like they are 1-5 feet in front of the muzzle before the muzzle flip :lol: :lol: That was with the Vaquero with light loads and the auto with Std. loads. :wink:
Don't know why or how and don't want to think about it. Will make my weee little brain hurt :roll:

That is when you notice the flip. The bullet notices it much sooner, we are talking about .001's of inches and milliseconds.

 

[Snake45]

You Guys need to watch the slow motion in Top Shot.
The bullets look like they are 1-5 feet in front of the muzzle before the muzzle flip :lol: :lol: That was with the Vaquero with light loads and the auto with Std. loads. :wink:
Don't know why or how and don't want to think about it. Will make my weee little brain hurt :roll:

That is when you notice the flip. The bullet notices it much sooner, we are talking about .001's of inches and milliseconds.

Correct answer. :wink:

If you think the muzzle's not rising before the bullet leaves the bore, lay a straightedge on your sights and look at the down angle the barrel is making with that line. If the muzzle's not rising, why are you not shooting a couple feet low?

 

[wildcatter]

Like 2 dogs said, you have to put it on paper to see, just to many variable to give any positive answer, gun balance change from another barrel, will you grip it the same, POI can change in the same caliber if you change from running the same bullet with a different powder to same velocity, handguns are kinda like woman, change the way you treat em in any way at all, they WILL REACT DIFFERENTLY!!! you can be sure of that!!!!

 

[Iron Mike Golf]

Also, shoot off a rest and really try to hold the gun down against the rest. Compare that with shooting standing, two handed.

 

[Pal Val]

+1 to putting a group on paper before deciding anything. There are just too many variables at play to make an exact prediction, unless you have a PhD in physics and a mainframe computer available.

Even then, you're likely to make a bad prediction... :roll: :roll:

 

[chris_]

I decided there were too many factors against this being what I wanted it to be so I passed on the gun. Too bad, though, I think it would be super cool to have a 10mm or even a 41 in a Vaquero. Shooting hot 10mm in my Blackhawk is like shooting 38 in an Sp101.