Do some guns shoot "flatter"?

[Walt Sherrill]

I was just reading a post here on the forum, about the new Hudson semi-auto, and problems the new owner was having getting a part replaced. He mentioned that he liked the fact that the Hudson seemed to shoot FLATTER than other guns he has owned. I've read this sort of comment about other guns, as well, including the SIG P210 . (I owned a P-210-6 for several years, and it was very accurate, but I never felt it shot more flatly than other guns shooting the same ammo.)

it seems to me that the only thing that really affects the bullet's path is the bullet's velocity. Some other variables are listed in the indented section, below, but I don't know that they make that big a difference.

I understand that there can be differences in bullet performance due to 1) the projectile's shape [i.e. aerodynamics] 2) the barrel's rifling, [i.e., the amount of spin/twist imparted to the bullet], 3) bullet weight, and 4) barrel length [which can allow some additional powder to burn before the bullet leaves the barrel, and possibly increase velocity], but most of those variables will affect the bullet's path, and the same rounds used in a different gun with similar barrel lengths (and maybe twist rates) will perform in much the same manner. I seems that most of THOSE variables affect velocity -- and any differences in performance are likely due to velocity differences.​

If a heavier bullet travels at the same speed as a lighter one, fired from similar guns, they're going to hit the target at the same time -- so the bullet path should be the same. (The fact that some bullets drop more than other has to do with the effect of gravity. -- with slower bullets taking longer to hit the target, which means gravity has more time to drag the bullet down.

Am I overlooking something more basic? Do some guns really shoot more flatly? If so, why?

 

[mcb]

One common possible context of shooting flatter is not about bullet trajectory but about how the gun recoils. Over most typical handgun ranges the flatness of the actual bullet's trajectory is a non issue. How the gun recoils is more important. A flatter shooting handgun in that context does not have the muzzle climb up as high during the recoil as another gun. USPSA open guns use compensators to direct propellant gasses up to make the gun run flatter. A gun like the Hudson tries to control the muzzle flip that comes from recoil by getting the axis of the bore as low as possible relative to the shooters hands reducing the moment generated. A flatter running handgun should allow you to get your sights back on target faster for a second shot. This what I think of when someone says a flatter running handgun. Certainly not the only interpretation but a common one. Hope that helps

 

[Zaydok Allen]

it seems to me that the only thing that really affects the bullet's path is the bullet's velocity.

I agree.

4) barrel length [which can allow some additional powder to burn before the bullet leaves the barrel, and possibly increase velocity], but most of those variables will affect the bullet's path, and the same rounds used in a different gun with similar barrel lengths (and maybe twist rates) will perform in much the same manner.

Yep, sounds right to me again.

If a heavier bullet travels at the same speed as a lighter one, fired from similar guns, they're going to hit the target at the same time -- so the bullet path should be the same. (The fact that some bullets drop more than other has to do with the effect of gravity. -- with slower bullets taking longer to hit the target, which means gravity has more time to drag the bullet down.

Exactly. If I'm shooting 45 Colt from my 460 mag at 50 yards, I have to aim a little high. Same bullet weight in a 460 mag, shot from the same gun at the same distance, and I just hold the sights on the target. That gun shoots flat with the 460 cartridge out to 75 yards or so. No so much with 45 Colt. Slower velocity = more gravity time, so it'll hit a little lower, all other things being equal.

Am I overlooking something more basic?

I don't think so.

One common possible context of shooting flatter is not about bullet trajectory but about how the gun recoils. Over most typical handgun ranges the flatness of the actual bullet's trajectory is a non issue. How the gun recoils is more important. A flatter shooting handgun in that context does not have the muzzle climb up as high during the recoil as another gun. USPSA open guns use compensators to direct propellant gasses up to make the gun run flatter. A gun like the Hudson tries to control the muzzle flip that comes from recoil by getting the axis of the bore as low as possible relative to the shooters hands reducing the moment generated. A flatter running handgun should allow you to get your sights back on target faster for a second shot. This what I think of when someone says a flatter running handgun. Certainly not the only interpretation but a common one. Hope that helps

That is one interpretation, but I do think you and Walt are describing two different things. What you describe, I've always thought of as the gun "runs flatter" meaning the muzzle rise is mitigated by design or by alteration. But I don't shoot competitively like you, so your lingo may be more accepted than my understanding of it. Walt seems to be wondering about "shooting flatter" as in actual bullet path.

 

[mjsdwash]

its exactly what mcb said. Shoot a 92fs and a CZ 75 side by side, and you'll really see why "flat shooting" is a decent way to describe it. Only problem, "flat" is a well known phrase applying to a specific trait. "Fast acquiring" would be a better phrase.

 

[Walt Sherrill]

A flatter running handgun should allow you to get your sights back on target faster for a second shot. This what I think of when someone says a flatter running handgun. Certainly not the only interpretation but a common one. Hope that helps.

Different folks apparently mean (or understand) different thing when they talk about a gun shooting more flatly.

If HOW THE GUN RECOILS is the issue, some guns do shoot more flatly than others.

I also agree that the amount of observed or felt recoil can vary greatly from gun to gun, and the experience of those differences are based on grip shape (ergonomics) and the level of the bore axis above the grip, gun weight, and slide weight. But some of those factors can be modified by shooting technique, by using recoil reduction systems, or by using different weight recoil springs. (One pro-shooter I know uses lighter recoil springs with buffers to increase slide speed without causing damage.) But when I see the topic of reducing recoil discussed, those folks don't seem to mention "flatter shooting" -- and if that IS what others mean when FLATTER SHOOTING is discussed, then I see that this discussion topic may have already answered the question.

FLATTER RUNNING is a better way to describe the behavior -- because then, it seems to me, you're talking about how the gun behaves and not how the bullet behaves. But I'll consider using "flatter running" in the future when this topic comes up.

 

[ATLDave]

mcb and mjs' have it: In pistols, the term "flat-shooting" nearly always means how the gun is perceived to recoil vertically, as opposed to straight-back.

A good way to understand this would be to consider USPSA/IPSC open-division guns. These guns shoot either 38 super +P+ or souped-up "9mm major" - rounds that are basically duplicating light-and-fast .357 magnum ballistics. The inherent mechanical recoil generated by these rounds is considerable... but open guns have compensators that redirect a lot of the exhaust gasses upward. This applies a bunch of downward force to the barrel. When you watch open-gunners shoot, their gun makes a huge noise, and it definitely smacks them in the palm... but the barrel doesn't tilt up dramatically. It often jumps vertically much less than a service-type gun shooting rounds that, by the physics, have only 2/3 of the recoil energy. That makes these open guns very "flat."

Some shooters will experience this as "less recoil," but the gun definitely smacks backwards with some force. It's not really reducing recoil much - just keeping things "flatter."

Outside of compensators, there are a bunch of things that go into how we perceive some guns to shoot "flatter" than others. Here's a fascinating set of old articles about it, including some of the opthamology involved. https://web.archive.org/web/20171108122611/http://re-gun.com/tag/flat/

The last thing I would add is that this kind of "flatness" is almost exclusively of interest to people who are trying to shoot fast. The "flatness" of a gun doesn't matter in slow fire - recoil matters, but flatness doesn't.

 

[1911art]

I fitted a Kart barrel to a 1911 wad gun, it fitted up tight and shot very well. It “shoots flat”, the gun shoots the same setting on the Ultradot sight at 25 yds and 50 yds. I’ve been to a lot of bullseye matches and it’s most common to come up 2-4 clicks from 25 to 50 yds on red dots for 45 wad guns.

It’s a barrel-sight alignment thing not trajectory.

 

[Zaydok Allen]

Hmmm. Seems an odd way to label it then, to me anyway. But whatever. The accepted lingo is the accepted lingo I guess.

This conversation really makes me wish there was competitive shooting in my area. All the emphasis in my area is on hunting and defense, and some of the terminology just doesn't drift my way unless on THR. the nearest league is a one way 40 mile trip from me, and my work schedule doesn't allow for joining.

Maybe a lingo sticky.................

 

[ATLDave]

Different contexts/disciplines have different terminology. In USPSA/IPSC, the distances and target sizes are generally such that bullet drop is not that big a concern. You might shoot 20 matches and never see a single shot where "hold over" or drop is a thing you worry about or deal with. On the other hand, being able to keep the recoil from popping the gun up and down dramatically is a big deal, and something you're dealing with on basically every stage and most shots.

Here's a slo-mo video of a very good shooter (Charlie Perez) who has exceptional recoil control - and the ability to hold his gun very "flat" despite shooting major power-factor ammo (without a comp - he's shooting a Limited-division gun).



You can see from the fact that his jowls are jiggling on every shot that the gun is coming back at him just as hard as the ammo's momentum dictates... but he's able to keep the muzzle from rising very much thanks to a combination of gun setup and (mainly) his exceptional grip stength and good grip technique.

What you're seeing in that video is what people who talk about a "flat shooting" pistol (in the practical shooting world, as opposed to, say silhouette or hunting) are trying to get to. Various gun configurations can make that easier or harder to achieve.

 

[PapaG]

New concept to me. Every reference to "flat" shooting in rifled firearms and to do with trajectory. Now, with shotguns, flat is used to refer to poi/poa as "that 870 shoots flat" meaning you have to hold right on the bird, whereas that "bt99, you gotta float the bird as it shoots high".
POI can vary just based on bullet weight. I had a customer years ago with a Remington replica 45 Colt that shot about 10" high at 25 yards with factory 255 grain loads. I had to go all the way down to 155 grain hbswc from an old Lyman mould made for the cap and ball Remington to get it to hit "flat" or poa. Successive loads from 255 to 230 to 220 to 185 and finally the 155 gradually brought poi to poa.

 

[Walt Sherrill]

I fitted a Kart barrel to a 1911 wad gun, it fitted up tight and shot very well. It “shoots flat”, the gun shoots the same setting on the Ultradot sight at 25 yds and 50 yds. I’ve been to a lot of bullseye matches and it’s most common to come up 2-4 clicks from 25 to 50 yds on red dots for 45 wad guns.

It’s a barrel-sight alignment thing not trajectory.

If it's a barrel-sight alignment thing, not trajectory, you're addressing bullet travel, not barrel rise due to recoil. That's what I was addressing, but most folks here seem to believe "flat shooting" addresses the GUN'S behavior, and not the bullet's behavior. Either way is OK with me, but I think FLAT RUNNING is a better term for gun performance.

And if your gun shoots to the desired point of impact at 25 and 50 yards (when other's don't) something else has to explain WHY there is a difference. I think it IS barrel-sight alignment in your example, as you say -- but I think the reason why your gun seems to perform differently is not the reason you think (i.e., a properly fit barrel)..

Most ammo makers show expected trajectories at 25 yards, with the 25 yard point being where the ammo is peaking in it's rise -- and the bullet starts to drop there after. Most handguns come from the factory with sights that will allow the shooter to hit the point of aim at 20 or 25 yards.

One explanation for the "seemingly" level hits at 25 and 50 yards you describe with your gun is that YOU have your gun sighted in so that the bullet is still rising as it hits the 25 yard mark and then dropping somewhere between 25 and 50 yards. The curve of the bullet's path isn't a perfect arc, as the bullet begins to drop faster as it gets farther and farther our, due to a loss of velocity.

I suspect that if you were to start shooting at a target at 30 yards or so, the POI would be a bit higher than at 25 yards, and at 55-60 yards you might be hitting lower than you'd expect -- as I suspect your bullet's arc is peaking between 25 and 50 yards.

This all seems consistent with what you've described, and would also explain why others have to raise their sights 2-4 clicks to hit the bullseye at 50 yards with the way their guns are sighted in. They've sighted their guns in differently. And I also suspect that were they to run your ammo, their gun's performance wouldn't change much unless your respective loads are quite different. (But even then you might not see much difference.)

Here's a chart by Chuck Hawks which shows the trajectories of some .45 acp loads. As you can see in this chart, the bullet hasn't stopped rising at 25 yrds. Here's a link to the Handgun Trajectory Table: https://www.chuckhawks.com/handgun_trajectory_table.htm

Chuck has not used 25 or 50 yards as the zero point -- but some point beyond 50 yards.
---------------------------------
To save space, the following abbreviations are used in the table below: Wb = Weight of bullet (in grains); MV = Muzzle Velocity (in feet per second); BC = Ballistic Coefficient; yards = yds.; inches = "; MPBR = Maximum Point blank Range.


Note: An expanded version of this table can be found on the Tables, Charts and Lists Page.
----------------Wb-----MV----------BC------25--------- 50 --------100----MPBR
.45 ACP (185 at 1000) ----- .109 --- +2.2" --- +2.8" ---- -3.7" --- 96
.45 ACP (200 at 975) ------ .138 --- +2.3" --- +3.0" ----- -3.8" --- 97
.45 ACP (230 at 850) ------- .195 --- +2.6" --- +2.5" ---- -6.9" --- 88
.45 Colt (200 at 1000) ------ .138 --- +2.2" --- +2.9" ---- -3.5" --- 98
.45 Colt (225 at 960) -------- .158 ---- +2.2" --- +2.9" --- -3.9" --- 95

 

[1911art]

Walt, your description is how I picture the flight of the bullet. I don’t think the tight fitting of the barrel is a factor but the alignment of the barrel in battery relative to the sight .
It’s a desirable situation for bullseye but it just happened and I wouldn’t know how to repeat it in another gun.

The load is a 200g SWC @ 750fps

 

[ATLDave]

Either way is OK with me, but I think FLAT RUNNING is a better term for gun performance.

That's fine, and I see your point in concept, but you've only got a few tens of thousands of practical shooters to convince. Calling guns "flat" or "flat-shooting" has been "a thing" for many years now in those circles.

 

[Walt Sherrill]

I'm not going to try to convince them, but when I deal with this topic in the future, I'm probably going to use both flat shooting/flat running for "flat shooting" and otherwise say clearly whether 'm talking about bullet behavior or gun behavior, and not leave it open to interpretation.

 

[ATLDave]

Truly, you are a gentleman and a scholar.

Although, as you note, there's no way physics can allow a gun to magically alter the flatness of trajectory of a bullet other than through velocity.* So someone talking about one 9mm service-sized gun versus another being "flatter shooting" is necessarily talking about muzzle rise.... or believes in the ballistic tooth fairy. I try to be a charitable reader, and so I will give them the benefit of the doubt unless the context dictates otherwise.

* At extended ranges, bullet spin stabilization does have some impact on effective BC, so that's something other than muzzle velocity that could cause a flatter or trajectory... but even that is only operating through its impacts on velocity at later points in the trajectory.

 

[Walt Sherrill]

I think a lot of shooters believe in the ballistic tooth fairy.

I think a lot of them also believe in the accuracy fairy who helps them consistently shoot sub-2" groups, off hand, at 25 yards, and the in the DA/SA transition training fairy who helps them shoot tight DA/SA groups with the first and second (or third) rounds at the start of a scenario. (I read about those results all the time, but seldom see it at the range or when scoring targets at a match. Guess the shooters where I shoot just aren't up to snuff -- or their eyes, like mine, just don't work like they used to work.)

I agree about bullet spin and bullet shape affect bullet performance, and mentioned it in my first comment. But as you say, it's at the greater distances that this really matters.

 

[ATLDave]

And of those two, a gun can only alter one... I mean, unless the feeding mechanism is really mangling the round on the way into the chamber!

 

[lysanderxiii]

If a heavier bullet travels at the same speed as a lighter one, fired from similar guns, they're going to hit the target at the same time -- so the bullet path should be the same. (The fact that some bullets drop more than other has to do with the effect of gravity. -- with slower bullets taking longer to hit the target, which means gravity has more time to drag the bullet down.

Exactly. If I'm shooting 45 Colt from my 460 mag at 50 yards, I have to aim a little high. Same bullet weight in a 460 mag, shot from the same gun at the same distance, and I just hold the sights on the target. That gun shoots flat with the 460 cartridge out to 75 yards or so. No so much with 45 Colt. Slower velocity = more gravity time, so it'll hit a little lower, all other things being equal.

You are assuming the two bullets loose velocity at the same rate, i.e., their drag in the same. Which is not a good assumption.

A 220 grain round nose .308 hunting bullet with a muzzle velocity of 2300 fps is going to have a completely different trajectory than a 220 grain boat-tail match bullet with the same muzzle velocity...and both will be different from a 150 grain flat base spire point at 2300 fps.

 

[ATLDave]

You are assuming the two bullets loose velocity at the same rate, i.e., their drag in the same. Which is not a good assumption.

I think in this case it's a fine assumption because the question was whether the GUN would make for a flatter trajectory - not different bullets.

Then we cleared up the confusion and established that the phrase "flat shooting" was being used to refer to recoil characteristics, not trajectory.

 

[Zaydok Allen]

I think in this case it's a fine assumption because the question was whether the GUN would make for a flatter trajectory - not different bullets.

Then we cleared up the confusion and established that the phrase "flat shooting" was being used to refer to recoil characteristics, not trajectory.

Yup, and we are talking autoloaders in the pistol forum.

@lysanderxiii

Not rifle rounds. But I do agree, bullet type is important when talking rifle cartridges.

 

[JR24]

That's fine, and I see your point in concept, but you've only got a few tens of thousands of practical shooters to convince. Calling guns "flat" or "flat-shooting" has been "a thing" for many years now in those circles.

Agreed.

I honestly thought this was common parlance in the gun world. It never once occurred to me that people would somehow link the trait to ballistic properties when referring to handguns.

 

[ATLDave]

I honestly thought this was common parlance in the gun world.

Just proof that there is not one “the gun world.” There are several! And they each have their own dialect.

 

[Walkalong]

So the gun doesn't shoot "flat", the shooter shoots "flat".

his exceptional grip stength and good grip technique.

Amen to that, wow is all I can say.

 

[entropy]

Well, a projectile will go farther the faster it goes, gravity being what it is. It may not be more accurate at a faster speed, due to other factors.

Never heard of 'flat shooting' being used for pistols; Of course, there are 'flat shooting' pistols, but they are usually in rifle calibers........

 

[Walt Sherrill]

Well, a projectile will go farther the faster it goes, gravity being what it is. It may not be more accurate at a faster speed, due to other factors.

But, if a round is faster -- i can be just as accurate and drop less for a given target than a slower round. That's a given

Never heard of 'flat shooting' being used for pistols; Of course, there are 'flat shooting' pistols, but they are usually in rifle calibers........

I started this discussion.

I've heard the term used with pistols, but in seemingly two different ways. And it has been stated in this discussion, rightly I think, that "flat shooting" is used differently by those who shoot in the (hand-)gun games and those who are more focused on rifles.

With the gun gamers, "flat shooting" seems to refers to less visible barrel rise during recoil -- i.e., how the GUN behaves. A few of us never quite understood that. The rifle folks tend to use :"flat shooting" to describe how the bullet behaves. But a lot of handgunners don't shoot in the gun games.

I was never much into rifles, but have done a lot of handgun shooting along with a bit of gun gaming. I heard the term "flat shooting" used, but never in a consistent manner; when I saw or heard it used, some folks seemed to think it addressed guns that shot with less recoil, while others felt that some guns just made bullets behave differently.

Like you, I appreciate that velocity and gravity are the main factors that controls the bullet's behavior. (Some other factors are bullet shape/aerodymics and spin rate.) I think everyone here generally understands that velocity and gravity are key, but not everyone involved in this discussion has fully come to understand that the two groups have been using the term "flat shooting" differently.

As I said, I'm going to try to say flat shooting/flat running when I describe GUN behavior.