What has more effect on POI, muzzle velocity or recoil.

[Doug Fay]

Hey! I just noticed I've been promoted to 40 Cal on the forum - whoopie! Is that just because I've made a certain number of posts?

 

[russellshaffer]

Mr De Land did start this in the muzzleloading handgun section, so here is my two bits worth. Stock design has a lot to do with muzzle rise due to recoil - a Kentucky type or revolver will move a lot more than a TC Patriot due to the thrust line. A light pistol will move more than a very heavy one and I think most people will agree. So, a light Kentucky will move more than a heavy Patriot with the same load. Still agree? We have to get to a pretty long pistol range before velocity and trajectory affect poi very much. Rifles are different of course. It's an interesting question but you still have to work up the right load for each gun. Exactly why impact point changes really doesn't matter much. We just have to know that it happens and load accordingly. It's fun discussing it.

 

[Doug Fay]

Mr De Land did start this in the muzzleloading handgun section, so here is my two bits worth. Stock design has a lot to do with muzzle rise due to recoil - a Kentucky type or revolver will move a lot more than a TC Patriot due to the thrust line. A light pistol will move more than a very heavy one and I think most people will agree. So, a light Kentucky will move more than a heavy Patriot with the same load. Still agree? We have to get to a pretty long pistol range before velocity and trajectory affect poi very much. Rifles are different of course. It's an interesting question but you still have to work up the right load for each gun. Exactly why impact point changes really doesn't matter much. We just have to know that it happens and load accordingly. It's fun discussing it.

I'm going to say I think you're right in most cases. But for my .62 cal flintlock pistol they seem to matter a lot (which is my main reason for jumping in here).

In fact, when I fire the darned thing at a target, I'm more likely to get a crow flying overhead than hit the target - well that's a bit of an exaggeration, but pretty close.

I've worked out an equation of that addresses relative "kick" or recoil you feel as a function of pressure generated by the propellant, mass of the round ball, and length of the barrel. It's useful for answering questions like, "what if the barrel were half as long?", and what if the caliber was 30% smaller?", What if I used round balls made of iron instead of lead"... that sort of thing. Anyway, one thing it tells me is that the large caliber and 12" barrel length has a lot to do with it. Anyway, I'll post that here when I'm sure it's correct.

And then, as you say, how that "kick" translates into barrel rise depends on a whole lot of things, like whether the gun is somehow bolted firmly to the earth (no muzzle rise), how firmly I hold it,) how far my wrist "pivot point" is below the center line of the barrel, etc.

Anyway, my hope is to figure out how to hit more targets and not be as much of a danger to birds with my flintlock pistol

 

[oldschoolhunter55]

If you hold the rifle upside down will the barrel go up or down?

good question

 

[flatcreek]

Not really! the stock is not in line with the bore and being it is lower than the barrel the barrel goes up! "For every action there is an equal reaction" !

Newton's third law is an opposite and equal reaction, the bullet goes straight out the barrel the barrel goes straight back. Everything else is caused by outside forces. ie the person holding the gun.

 

[LME]

Newton's third law is an opposite and equal reaction, the bullet goes straight out the barrel the barrel goes straight back. Everything else is caused by outside forces. ie the person holding the gun.

Right! My target rifle has a straight stock and it recoils straight back but my hunting rifles have a typical rifle stock and rises!!

 

[Doug Fay]

Right! My target rifle has a straight stock and it recoils straight back but my hunting rifles have a typical rifle stock and rises!!

I've noticed a lot of shooters (including competitive) putting the butt of the stock into their shoulders right at the top of the butt, almost on the top corner. Makes me wonder: at least for high precision shooting, why aren't the middles of the stock butts made to be more in line with the centerline of the barrel?

 

[LME]

I've noticed a lot of shooters (including competitive) putting the butt of the stock into their shoulders right at the top of the butt, almost on the top corner. Makes me wonder: at least for high precision shooting, why aren't the middles of the stock butts made to be more in line with the centerline of the barrel?

If they were made that way the sights would have to be way to high. A stock drops down so your eyes will be able to see down the sights.

 

[russellshaffer]

High stock butts are not a new idea. It has been done before.

 

[Doug Fay]

High stock butts are not a new idea. It has been done before.

View attachment 347408

Very cool! So old it almost looks modern

 

[SOLANCO]

Any effect of recoil will be largely related to a tendency to flinch.

 

[nkbj]

it is all about barrel whip.
that is why when you shoot .38 ammo out of a gun that was sighted in with .357 ammo hits a foot high. It stays in the barrel longer

Thank you for stating the obvious only to be ignored. Have you noticed that happens a lot around here?
Percussion revolvers behave the same way because it doesn't matter one iota that they don't use brass cartridge cases. Change the bullet weight and/or the powder charge and you'll get a change in elevation.

 

[Rum River]

it is all about barrel whip.
that is why when you shoot .38 ammo out of a gun that was sighted in with .357 ammo hits a foot high. It stays in the barrel longer

It actually works out the other way for me. I can't help it, the target paper didn't lie to me.
Lighter recoiling calibers in whatever firearm never print higher for me. It's always either the same as or lower than a heavier recoiling caliber.

My opinion on why this happens is that while a slower projectile is in the barrel longer - a faster projectile is also producing a larger amount of recoil.

Example - I personally witnessed this, for real, I was only a spectator.
Group of young guys sitting in the living room of a house trailer with an unmentionable revolver. Said firearm had been sighted in with heavy loads. Group of fools decided it was okay to target practice with primer-only powered "synthetic" ammunition using an empty KFC bucket - which was sitting on the dust cover of a stereo turntable.

The result was a very tidy group - that was several inches below point of aim and went through both sides of the stereo dust cover.

By the way, I'm really enjoying this thread - lots of give and take.

 

[#BPBReloadingFFL]

This vid shows a tiny amount of muzzle movement, but movement does start before the bullet leaves.
I'm going to try and find a slow mo video of some muzzleloading examples.

While the video shows reward movement it does not show rise.
Ported vs non ported
Once upon a time I took several firearms and set cardboard on the bench next to the muzzles. Taped a marker on the muzzle. Set firearm in a rest-string on trigger-touched off the cartridge. You'd be surprised at the jump.
Now holding onto a firearm and touching one off is different than sitting in a fixed rest.

Sitting at a bench,(your position); vs off hand has a different effect on felt recoil as well as rise. You have the flinch factor-anticipating the shot-your physical size-weight of firearm so on & so on.

You want to see what happens ? Set a camera facing your side while you shoot. Not for one shot but your entire range time. The look at the video and see your inconstancies, stance, seated & rest positions.

If your thinking about all the possibilities they are distracting you - then your not concentrating on shooting!

 

[Rum River]

Does a flattened trajectory from velocity increase have more effect on vertical sight adjustment or does increase recoil and subsequent muzzle rise?

Well - it depends.

I still like my original answer..............lol.

 

[russellshaffer]

I agree with Rum - it depends - on a whole lot of variables. A person could settle it for himself by firing a bunch of rounds with varied charges and projectiles through the same weapon at different ranges. Then when you are done, you will have results that only apply to one shooter and one weapon and one firing position. I don't have that much powder, bullets, balls, and time. Or enough curiosity.

 

[M. De Land]

I agree with Rum - it depends - on a whole lot of variables. A person could settle it for himself by firing a bunch of rounds with varied charges and projectiles through the same weapon at different ranges. Then when you are done, you will have results that only apply to one shooter and one weapon and one firing position. I don't have that much powder, bullets, balls, and time. Or enough curiosity.

I posed the question realizing it is a multifaceted one and would require a number of pertinent answers.
I always start with load development to find a consistently accurate load capable of the distance and accuracy requirement needed and once the groups are equal to the task start the relatively easy part of the equation by making the sights center the group at the distance needed.
I always prefer the six o'clock hold for target , gong or game as it gives the most open sight picture, light gather and holds/registers both windage and elevation better than any other sight picture.

 

[Doug Fay]

Any effect of recoil will be largely related to a tendency to flinch.

Thanks - I have a strong feeling I'm doing that. I'll ask somebody to video me and then start working on it.

 

[Doug Fay]

A day or so ago, I said I'd work a formula to see how various changes might affect the amount of "kick" you feel when shooting. I call it "kick", but the technical term I use it for is "Impulse", or change in Momentum.

I'll put the formula below and talk about what it means for me with my .62 caliber flintlock - it really surprised me. But I've attached a more detailed explanation and derivation of the formula in a pdf document. Note: this version is for a gun shooting a round ball. The formula is:

"Impulse is proportional to the Diameter of the bullet, raised to the 5/2 power, times the square root of: [Pressure of the propellant gases times the length of the barrel times the density of the bullet material]" (used W for density):

Or, I ~ (D)^5/2 x (P x L x W)^1/2​

Anyway, one of the key realizations is that small changes in the diameter make big changes in the Impulse. For example, double the diameter, and the Impulse, or kick goes up by a factor of more than five. However, double the barrel length, and the kick goes up by less than 50%.

I'm no longer surprised by the kick and barrel rise of my 62 caliber Flintlock.

Anyway, this was fun to do, and I hope it's helpful. I also hope it's correct - if you find and problems or questions, let me know.

 

[Pete G]

Until the laws of physics are repealed, recoil begins the moment the bullet begins to move.