"Bore Line" and Perceived Recoil
This is a discussion on "Bore Line" and Perceived Recoil within the Defensive Carry Guns forums, part of the Defensive Carry Discussions category; So I'm currently stuck on figuring something out about perceived recoil, and as the title indicates, it's what's been described to me as "bore line" ...
December 18th, 2007 11:50 PM
"Bore Line" and Perceived Recoil
So I'm currently stuck on figuring something out about perceived recoil, and as the title indicates, it's what's been described to me as "bore line" height.
At every course I've been to, and every range I've visited where the discussion of handguns has come up, I hear mention of "bore line". My basic understanding of what folks are saying is that the lower the bore line, the less perceived recoil you'll feel. The most cited examples of this are Glocks and 1911's. My own experience is almost entirely with Glocks; I grew up on a G17 specifically, and have always found myself to be pretty accurate shooting Glocks of all flavors.
So here's the question: is this "low bore line means less felt recoil" BS or legitimate? Physics wise, I can see where it has merit, but the height of the bore in a Sig compared to a Glock really isn't that different, is it?
(I mention Glock, Sig, and the 1911 specifically because the bore height appears to be the only thing non-Sig shooters knock about Sigs, and those three types of pistols are the three I'm hovering between for picking a near-future carry gun.)
December 19th, 2007 12:07 AM
Each person is different in their own perceptions. Personally, I think people make these topics far more complicated than they need to be. I really dont notice recoil anymore at all in the 3 major calibers, no matter the pistol unless I'm trying to notice to compare or whatever. It isnt that tough to shoot any pistol in the common calibers, so yes, in that sense I think its toro caca.
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December 19th, 2007 12:11 AM
December 19th, 2007 12:29 AM
I see your point Tubby, and that's consistent with the physics of the idea, but I couldn't honestly tell when shooting casually the difference between the .40 and .45 subcompact Glocks when I shot them, where physics would also dictate they would feel differently.
How well does the pen example translate to a firearm, though, all other things being equal? As I pointed out, while there is a difference in relative bore height between Glocks and comparable-sized Sig's, it isn't really very much of a difference, so I'm wondering if it's enough to produce a difference in felt recoil.
I find it hard to argue against "higher bore line" guns like Sigs considering what professionals use them, and I'm certainly not buying a gun for competition purposes.
December 19th, 2007 12:42 AM
It's legitimate physics. I won't go into it (it would break my brain to try to remember all of it), but if you feel saucy and want to read up on it, check this out.
In layman's terms, the muzzle rise of a given firearm is due to the force exerted by the reciprocating mass about the center of mass of the firearm. As the center of mass is brought inline with the direction of the applied force, the recoil changes as well, from a rising motion to a rearward motion.
December 19th, 2007 01:03 AM
I personally don't notice much difference in Glocks to any other brand on gun. XD's, HK's, 1911's ect all seem to be about the same in recoil.
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December 19th, 2007 01:03 AM
That was my illustration of the principle. I do not have the scientific knowlege to explain it.
Originally Posted by BAC
Some say it makes a difference, some say there isn't any measureable. I shoot Glocks and 1911s, both of which have low bore axis, so I have no experience with the high bore axis guns other than the Ruger GP100 revolver. That has a very high bore axis, even though it is apples to oranges, the felt recoil and ballistics are a twin of the full power 10mm. The GP100 will flip more with full power .357 Mag than my 1911 will with full power 10mm.
December 19th, 2007 01:05 AM
They sit pretty low in the hand.
Originally Posted by rocky
I've heard this claim a lot. Usually about the SIG bashers. I've never shot a SIG so I can't comment on the recoil characteristics of their fine weaponry. (Itching for a 220SAO).
December 19th, 2007 02:21 AM
I don't know about less perceived recoil, but it seems to have faster shot to shot times. The recoil argument makes sense when you picture the amount of displacement allowed as the height of the barrel increases. Kind of like having more torque with a longer lever arm.
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December 19th, 2007 07:03 AM
2 things - recoil force and muzzle flip
I think you have to separately define the concepts "recoil" and "muzzle flip" to talk about this subject. I think of recoil as the force backwards along the bore axis of the gun due to the pressure in the firing chamber. Because the cartridge case containing the pressure is in contact with the breech block of the gun, a backwards force is exerted, equal to chamber pressure times the area of the round base of the cartridge case. The force varies over time because the chamber pressure varies over time (as the bullet is traveling down the barrel).
I would define muzzle flip as the rotational torque exerted by the recoil force because the muzzle of a handgun normally sits higher than the center of mass of the gun, and also higher than the "hinge point" of the human wrist. The muzzle flip causes the gun barrel to rotate upwards somewhat with each shot, until the shooter and gravity bring the barrel back down on target for the next shot.
I don't believe that recoil force is affected by the bore axis of the gun relative to the shooter's hand or the gun's center of mass, because it depends on chamber pressure and cartridge diameter. But the muzzle flip does depend on hand position and gun geometry, as well as the strength or size of the shooter's hand and arm.
In "free pistol" competition, there have been some .22 target guns developed that try to minimize muzzle flip by positioning the shooter's hand very high relative to the gun's barrel. The Hammerli free pistol below shows this:
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December 19th, 2007 08:26 AM
The reason, of course, is that bore axis is not the only difference between Sigs and Glocks. There's: weight, grip ergonomics, gun construction. All these are factors, so you really can't determine the effect of bore axis in isolation.
Originally Posted by BAC
Keep in mind: since the Sig is heavier than the Glock AND you can't tell the difference in recoil, that tells me that the bore axis advantage is cancelling out the less-weight disadvantage.
December 19th, 2007 08:32 AM
I think perceived recoil is just that - how we perceive or sense it. But perception does not modify or change reality. Reality is, we have to deal with recoil whether we perceive it or not.
Although from years of personal experience shooting Glocks, Sigs, and 1911s, and more lately S&W M&Ps, my position is that perceived recoil is different with some guns. First I don't know how the 1911 gets the "low bore" category. Here are some measurements - measurements were made from the firing pin or striker to a similar point on the 'beavertail' of each gun. Obviously this results in a non-precise measurement because the point that is critical on the beavertail is ill-defined, so I tried to estimate the same point on each gun. But the differences will probably be surprising.
Glock...............13/16"; the M&P would be very close to the same.
Notice the 1911, Sig, and Beretta have essentially the same bore height, and to my surprise the XD has a relatively low bore height, and no surprise, the Glock and M&P are significantly lower than the other guns listed.
I can't tell you how many times I've read that a 1911 has a low bore height.
The differences are significant enough to produce significant variations in recoil. But there are other considerations as well, like the weight, and weight distribution of the gun, and in fact, how much ammo is in the gun.
It is possible that a gun with a higher bore on a steel frame (e.g. a 1911) may not produce any more muzzle lift than a gun with a lower bore on a polymer frame. Why? Like someone has already mentioned - inertia. The heavier weight of the frame resist motion in any and all directions, including lift and rearward thrust.
But, all things being equal, and they rarely are, a gun with a higher bore will produce more muzzle lift than a gun with a lower bore. Likewise, a gun with a lower muzzle will produce more rearward thrust than a gun with a higher bore.
When I shoot a Glock and Sig side-by-side, and I pay attention to recoil, the Glock's recoil seems sharper and the Sig's recoil seems to lift or roll more.
So which is better? I don't think it matters in the least. All recoil has to be absorbed, regardless if it's mostly straight back or more muzzle lift. I can not tell any advantage either way. The gun alignment is disturbed either way, and using my timer, I cannot see significant differences in recoil recovery. In fact, I seem to be able to shoot faster with a Sig DA/SA than with a Glock, which suggests that the trigger travel time and trigger characteristics, i.e. pull weight, travel distance, over travel, and reset travel may have as much to do with fire rate as recoil recovery.
If you are using proper techniques in grip etc., I doubt you'll be able to measure a lot of difference in the effects of bore height, or that you'll be able to isolate problems to bore height alone. After all, 1911s dominate bull's eye competition and they have one of the highest bore heights of any gun.
Ahhhh, dgg9, we were posting at the same time. After I posted, I read your post and see that we said just about the same thing.
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December 19th, 2007 10:45 AM
That's one reason instructors will tell you to get as high a grip as possible on your gun, so as to get that bore line down. There are other reasons too but it does help absorb recoil and keep the muzzle down.
For an exagerrated example, grip your gun low on the grip and fire it. Then get a high grip and fire it. You will feel the definite difference in muzzle flip. A high bore line isn't always noticable but can affect recovery times to a small degree.
December 19th, 2007 11:46 AM
December 19th, 2007 12:14 PM
Beyond bore height, IMHO I think that grip angle makes a huge difference.
For me the XD45 feels much more slide heavy than a Glock 21, which I attribute to the more severe grip angle on the Glock.
The more vertical the grip the more pressure is put on the top of your hand near the thumb which is the most unsupported place on your hand.
With a steeper grip angle, the recoil is coming more directly through your hand and into the arm.
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