200 vs. 230gr .45 ACP's

[44 AMP]

No,what force is pushing up the slide is not an opinion of what may be pushing up the slide if at at all during recoil.

I'm not sure what you are trying to say here...
Unload your pistol or use anything "L" shaped in your house (hair dryer, carpenter's square, etc.) Hold the grip normally in one hand, (one arm of the "L") slap or push sharply on the far end of the other arm, straight back simulating recoil.

What does the gun try to do? Twist (rotate) in your hand. Slide movement isn't happening, but the muzzle still rises. The same rise happens in revolvers, single shots, rifles, shotguns, any and every thing where the weapon is held or mounted below the line of the bore.

If you can't wrap your head around this, then I suggest seeking a different hobby.

[polyphemus]

This thread was about bullet weight affecting trajectory.Reloading topic.
Then Sir Issac showed up and next,came suggestions of wrapping heads around things and changing hobbies,nice going moderator.Not a reloading topic.
So in the interest of furthering understanding why don't you open a thread where it belongs and a discussion of the subject can take place with firearms based evidence and not carpenters square analogies.?

[Unclenick]

Polyphemus,

You are digging yourself into a deeper hole. The recoil physics being discussed are precisely what change the vertical POI with bullet weight which is what the OP wants to find a way to compensate for. They also explain why he will have a difficult time trying to achieve matching POI by loading the lighter bullet hotter.

Here's what you seem to be missing: When pressure is made in the case, force is applied to the base of the bullet to propel it forward and, simultaneously, an equal and opposite force is applied to the breech end of the gun by that same pressure. That is the force creating the muzzle rise. Here is the mechanism:

In illustration 1., below, you see a force applied to an object with a pivot and it is not directed straight into the axis of the pivot. The result is torque which turns the object around the pivot. This is the same principle as pushing on a wrench handle to turn a stubborn bolt. If you then add a side extension that is aligned with the direction of the previous force, you get the same result (see figure 2.). It's no different than pushing on the wrench handle would be if your forearm suddenly got longer. If, as in figure 3., you reshape the pivoting object and extension like a gun, and you replace the force from your arm with the equal and opposite bullet propelling force and move the pivot to the center of support from the flesh of your hand, you can see you get torque that turns the gun on the vertical plane.

The force is applied all during the time the bullet is in the barrel, so the rotation has to be accelerating during that time, even though part of it is absorbed by starting the slide back, it also starts the barrel back if it is a locking design, tipping the muzzle up. Even in a straight blowback design, force is being applied against the frame through the recoil spring and through cocking effort. Unless you can make that zero, the muzzle will start to rise before the bullet gets out. And in a revolver or single-shot handgun, you don't even get that level of recoil absorption.

If the barrel were lined straight up with the pivot point, no torque would result and the muzzle would not rise. This is the idea behind barrel placement in a bullpup military rifle design. It is to eliminate muzzle rise in full-auto fire. Also, in the 1950s the Russians had Olympic rapid fire pistol designs that placed the barrel straight in line with the shooter's arm and had the sights extended way up above the barrel. The extensions made the barrel look like an inverted hacksaw frame, so these were referred to as hacksaw guns. I believe they were banned by the rules, as controlling muzzle flip was considered part of the competition. At any rate, they disappeared. But that gives you an idea how handgun design would have to change to avoid this issue of POI changing with bullet mass.



So, why is the change in bullet mass causing a POI shift? Even if the load pressure and amount of gas were identical for the two bullet weights, as they are in an airgun, the heavier bullet's greater inertia will cause it to take longer to exit the bore than a light bullet does. This gives that same force more time to accelerate the gun mass around the pivot before the bullet clears the muzzle, so the bullet exits when the barrel is more elevated, raising the angle of departure and, with it, the vertical POI.

Handgun shooters have long observed that bullet weight has more effect on point of impact than charge weight does. Increasing charge weight will raise the POI a little by pushing harder on the bullet and increasing the equal and opposite reaction force on the breech end. However, this also means the bullet gets out of the barrel faster so the greater force doesn't act for as long. It's not proportional because acceleration is a square function, but you do have to add a lot of charges to raise the POI of a lighter bullet to meet that of a heavier one, and it often isn't withing practical pressure limits of the cartridge.

An exception often occurs at longer range. A big, heavy bullet will have a high, arcing trajectory and since gravity accelerates heavy and light bullets at an equal rate, you can often find a distance where the heavy bullet has fallen to intersect the trajectory of a lighter, faster bullet. At that magic range, POI will match. Beyond it, the heavier bullet's POI will be lower. But for the short ranges most folks use a defensive handgun with, heavy bullets will impact higher and unless you are comparing a much reduced heavy bullet target load to a hot lighter bullet load, you won't likely make up the difference.

[F. Guffey]

Search the web and you'll find slow-motion video that shows the gun move and rotate before the bullet leaves the barrel.

Good luck; I made an effort to convince the same group gas escapes past the bullet and out of the bore before the bullet makes its appearance. There were many reloaders that invested a lot of time being rude with no way to get back.

I explained to them I had a picture that was over 100 years old that won a beauty contest and was considered art. The picture explained the sequence of events that took/take place when a round is fired.

F. Guffey

[polyphemus]

Thanks UncleNick
Long response there with much to mull over plus I'm in a deep hole so it may take me a few posts.OP's arm is a commander style 1911
The bullet is dragging the barrel along on its way out plus miscellaneous springs slide mass and friction are delaying recoil untill the bullet exits.In other words your barrel has had precious little time to do this rise and precious little slide momentum to pivot anything when it could have had an influence on aim.After that it is irrelevant.

[Metal god]

WOW , I feel there's a ghost of Jeephammer lurking about

[polyphemus]

This is not about annealing.

[Metal god]

Agreed it's about a member unwilling to except facts , but hey maybe we are just spewing the same old dogma .

[polyphemus]

If Jesus had a gun , he'd probably still be alive !

And we probably not have christianity.
Show me the facs I'll accept them

[USSR]

polyphemus,

Don't change the subject by going after somebody's signature. You've got all the facts you need and you refuse to accept them. Unclenick spent a lot of time putting together post #28 simply for your benefit. What's not to believe about it?

Don

[Metal god]

It's all good , I deserved a little pocking back , I was having a little fun with the Jeephammer remark .

As far as show you the facts , I did in the video I posted showing a revolver recoiling/moving before the bullet leaves the barrel . Then there's Newtons "law" but you may not be familiar with that word in that context . In that context it means to be true without debate . If we're not throwing out Newtons law then you are wrong period and that's MG's law

[polyphemus]

So, why is the change in bullet mass causing a POI shift? Even if the load pressure and amount of gas were identical for the two bullet weights, as they are in an airgun, the heavier bullet's greater inertia will cause it to take longer to exit the bore than a light bullet does. This gives that same force more time to accelerate the gun mass around the pivot before the bullet clears the muzzle, so the bullet exits when the barrel is more elevated, raising the angle of departure and, with it, the vertical POI.

But they are not identical,we are increasing the velocity and momentum by raising the powder charge.
So the impulse force is greater for the lighter bullet but momentum is the same
mxV ok? Air guns.recoiless rifles revolvers they handle opposite forces in different ways and to mix them for the purpose is simply disingenuous

[Metal god]

revolvers they handle opposite forces in different ways and to mix them for the purpose is simply disingenuous

No they don't , All firearms have the same initial physics when the hammer hit the primer , gases start to expand and bullet starts to move . All that happens exactly the same regardless of the type of firearm . As soon as the bullet starts to move forward there is and equal and opposite reaction . All of that happens before anything opens or starts sliding rearward .

[44 AMP]

The bullet is dragging the barrel along on its way out plus miscellaneous springs slide mass and friction are delaying recoil untill the bullet exits.

No, they don't delay recoil. Recoil begins as soon as the bullet starts moving down the barrel. Don't confuse recoil with the mechanical movements of the firearm which USE recoil for their energy.

In other words your barrel has had precious little time to do this rise and precious little slide momentum to pivot anything when it could have had an influence on aim.After that it is irrelevant.

Yes, there is precious little time involved. With a bullet travelling over 800 fps down a barrel less than 5 inches long, the time involved is very short.
You are correct that recoil doesn't have an influence on AIM, but it does have influence on point of impact. Gunmakers take this into account.

Neither you nor I can recognize the small amount of muzzle rise from recoil while the bullet is still in the barrel, but it is there, and it does have an effect.

[polyphemus]

The Phyisics are the same but the Mechanics are not.
Read up on floating chambers that may prove instructive

[Brutus]

OK so the bottom line is shell out $70 bucks for some 230 grainers to shoot out of my fixed sight commander, get a different front sight or live with it and compensate. Guess I'll compensate for the time being.
Thanks for all the feedback it is very interesting if not somewhat brain numbing.

[74A95]

Originally Posted by Brutus

OK so the bottom line is shell out $70 bucks for some 230 grainers to shoot out of my fixed sight commander, get a different front sight or live with it and compensate. Guess I'll compensate for the time being.
Thanks for all the feedback it is very interesting if not somewhat brain numbing.

A 2" difference in POI is not much, but you now know that the POI is different, so compensating, or just adding a 2" measurement to your final POI is not difficult.

[pete2]

If you are gonna stick to the 200 gr bullets, replace or file down the front sight. I shoot 200s in my .45s. I have had to file the front sights on some of them, they'd have been low with 230s also. In fact I don't notice much difference in impact between 200 and 230 in my 1911 guns, whether 5" or Commander. Recoil seems to have more effect in revolvers in my experience. The longer the bullet stays in the bbl the higher the impact on the target. I once shot some 110 gr .357s in a gun sighted for 170 gr bullets, the 110s shot about 6" low at 25 yards.
In the .45 sighted dead on with 200s will only be a couple inches high with the 230s. For me 2" high is great, preferred in fact. Except for Bullseye competition, 2" high is better. I want to see the target, not hide it under the front sight.

[polyphemus]

No, they don't delay recoil.

From the words of the Creator:
and as on
firing a shot the inertia of the heavy breechslide
and of the barrel delays the rearward
movement of these parts until after the bullet
has passed from the muzzle of the barrel,
But of course you know better than Browning,right?

[polyphemus]

Recoil (often called knockback, kickback or simply kick) is the backward movement of a gun when it is discharged

It is what it is

[Bottom Gun]

I would try slowing the 200 gr load down to make the bullet spend more time in the barrel as it's rising.
OR
Try a different powder in hopes of changing the POI.

I would try reducing the powder charge first to see how much difference it makes in your POI.

[polyphemus]

Thanks for all the feedback it is very interesting if not somewhat brain numbing.

Don't say that man,just tweak your loads untill you get it right,you will eventually and all this controversy will have meant zip.

[74A95]

Originally Posted by polyphemus

From the words of the Creator:
and as on
firing a shot the inertia of the heavy breechslide
and of the barrel delays the rearward
movement of these parts until after the bullet
has passed from the muzzle of the barrel,
But of course you know better than Browning,right?

Let's hope Browning didn't mean that there is no movement of the slide until after the bullet has left the barrel, because we know that isn't true, and it would defy physics, which it doesn't.

The video link I posted earlier is visual evidence that the slide does indeed move before the bullet exits. If Browning really thought that it didn't, he was clearly wrong, proven by his own gun.

[74A95]

Browning might also have been using the term 'delay' to mean something different. Delay, might mean slowing down. But this different than using the term delay to mean preventing, as might be the definition used by some folks here.

[44 AMP]

From the words of the Creator:
and as on
firing a shot the inertia of the heavy breechslide
and of the barrel delays the rearward
movement of these parts until after the bullet
has passed from the muzzle of the barrel,

note the bolded text. It doesn't say the parts don't move only that their inertia delays movement until the bullet is out of the barrel.

However, this is beside the point. The force of recoil lift the muzzle of the pistol beginning as soon as the bullet begins moving and continues to lift the muzzle after the bullet has cleared the barrel. A lighter bullet, moving faster, spends less time in the barrel as it raises in recoil than a heavier one. The heavier, slower bullet takes longer to exit the rising barrel, and therefore strikes higher on the target than the lighter bullet.

This same principle is at work in revolvers and single shots, it has nothing to do with slide movement or timing. Now the mass of the moving slide. and its sudden stop, and its movement forward again, and that sudden stop does affect what you feel in your hand when firing. This is "felt recoil" and is subjective. All the energy of all the moving parts comes from the powder gas, the moving parts of a semi auto don't change that, they just alter the way we feel it.

As I and others have suggested, if you reduce the velocity of the 200gr so it spends the same amount of time in the barrel as the 230gr, it should strike the same point of impact as the 230. These will feel like very light loads, but shout hit the same point of aim, at regular pistol distances. Longer range has additional factors which can change things.