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Re: Shooting high

Posted: 20 Jun 2021 19:36
by Reese-Mo
Sigh. Its proportional. You cant get around the physics.

Just go read Hatcher. All the math is there, and its fairly easy to understand.

Re: Shooting high

Posted: 23 Jun 2021 07:43
by Blind Hawg
I went with a 5/8" tall patridge front blade and filled it down to work with the safety aperture rear. Its been said that you can center that bullseye on the top of the flat blade surface easier. Brass beads fall off, at least mine did.
***Make sure whatever front blade you get that it is oversized for Rossi dovetail.

Re: Shooting high

Posted: 23 Jun 2021 11:14
by Moe Mentum
I also put a taller sight on my 92, was shooting high at 50 yards.

Re: Shooting high

Posted: 23 Jun 2021 14:55
by Blind Hawg
No thanks, math hurts my brain

Re: Shooting high

Posted: 23 Jun 2021 18:00
by Reese-Mo
I JB welded a SureHit bead on my Win/Miroku. These have a groove that captures a standard bead, but aint too usable on Rossi

Re: Shooting high

Posted: 24 Jun 2021 22:10
by HarryAlonzo
Thanks for the referral to Hatcher! I did not know of his book. I received a copy of the 640 page 1962 Stackpole reprint from the library today.

I went straight to the 20 page chapter "The Theory of Recoil." The biggest revelation for me was the influence of the powder mass on the system momentum. It's not only the bullet that's accelerating through the barrel, but the expanding gasses of the powder.

Regarding our particular discussion, I think the disconnect is rifle versus handgun. He doesn't discuss the impact of recoil on POI with rifles, but he does with handguns (Subchapter "Effect of Recoil on the Jump of Revolvers"). This is due to the elevated bore axis of the handgun, and the more pronounced rotation due to recoil. I would have defended my argument with handguns, too, but I bow to the science.

Re: Shooting high

Posted: 24 Jun 2021 23:21
by Reese-Mo
Its just a matter of degree with rifles. Also the ejecta of gasses from the barrel.... explains why shotty "brakes" dont work so effectively.

Re: Shooting high

Posted: 25 Jun 2021 12:16
by Archer
The gas effects can be a huge part of the energy and momentum equations.
That was part of the calculations in the barrel length calcs I mentioned before. It probably makes my point even more as the powder being burned outside the barrel adds no recoil but it's really hard to get a measure of that effect without quite a few oddball experiments. Even assuming the same gas effects the recoil was less in the short barrels due to the reduced velocity of the .308 or 5.56.

Re: Shooting high

Posted: 25 Jun 2021 18:41
by Reese-Mo
The total recoil energy consists of three parts.

1. The projectile in the barrel
2. Half the mass of the powder/gasses whole in the barrel
3. The volume of gas and its velocity as it exits the barrel

Using a pendulum, it was determined that the .30-06 gained about 40 percent of its total recoil from #3, known as the rocket nozzle effect. Different bore sizes change that effect, assuming volume and velocity remain constant..... why shotty brakes are minimally effective.

Re: Shooting high

Posted: 25 Jun 2021 22:20
by Archer
"The total recoil energy consists of three parts."
From the standpoint of the cartridge...

Recoil felt by the shooter is also going to include the effect of the weapon mass, in the case of semi autos the amount of energy that the action takes to function and the fit of the weapon to the shooter.

Or in other words, more mass in the weapon gets less acceleration toward the shooter.
Semi automatics tend to absorb some of the energy or spread it out in time while chambering another cartridge.
A grip or stock that fits the shooter spreads the energy out over more of the shooter. Bad weapon fit can concentrate that energy in less area and time and result in a painful experience.

Muzzle rise is going to take into account bore above support effects into account.
One of the reasons the AR has gotten popular is, in addition to the fact that .223/5.56 is a popgun round, is that the action/recoil/support path is pretty much all on the same axis so there's just not a lot of torque in the system.