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Ammuniton accuracy. free pistol, handgun, rifle

Posted: Thu Jan 10, 2013 2:29 pm
by J
Some very interesting comments on ammunition selection for a variety of guns have appeared on some TT discussions. These were particularly interesting from the point of view of people who don't use these guns in competition, and for whom a 600 free pistol score is at the beginner level and will not pass go for actual work.

These comments may have absolutely no relevance for those in competition shooting, but they still might be of interest.

Reprinted with permission, but without reference to source.

The following may be total junk for target shooters, but they may be something to think about. They are a summary of views from people who design and make precision guns, or use them for non-competition purposes mostly.


Ammunition:

What is the most important, and worth doing to get similar performance ammo?'

Cartridge dimension consistency, bullet mass and concentricity, symmetric bullet mass distribution, chemical consistency of the powder, grain size, and moisture content of the powder are important, but hard to sort after the cartridge is assembled. Best to "equalize" these by starting with cartridges that basically are well made. Most of the W European mfrs are in that category, and also in the past, the Olymp Moscow ones (not so much the TEMP). Examples range from SK/WolfMatch, Lapua, Eley, RWS, Fiocchi, GECO except the CCI produced ones, but there are others.

Once the general category of ammunition is chosen, the first sort is density of powder packing. The main factor in muzzle velocity and barrel vibration pattern is the flame temperature and burn speed. This is most sensitive to the free space between the powder grains, and is proportional to the cube of 1/(free space). Easiest way to measure this is by indirectly measuring the consistency of seating depth of the bullet. This is done by sorting using the top to bottom length of the cartridge, and sort to within .1 mm or .02" in groups.

This is especially important with cartridges that are "filled" with powder, like some 9mmXanything, or the 7.62 Tokarev, but also with those that are not filled completely. The design of the .32SWL WC cartridge minimizes the packing variation most of the time, making sorting by length usually not worth while for that particular cartridge, if the manufacturer is good.

Sub-sorting within groups by overall weight can help further, but to be honest, in the above mfrs, the powder and moisture content is so well controlled, usually there is very little difference. Usually the powder is pretty consistent between cartridges. What can differ is moisture content, which this also measures.

The third option in sorting is rim thickness in .22RF, but this actually has little effect. Primer ignition is a piezoelectric effect, with little dependency on rim thickness. Primer burn rate and temperature vary a bit with rim thickness, but not enough to be worth measuring. In the past, rim thickness measurement did help a bit, but it should not have. I think the reason it did help is what with lower quality cartridges and poor manufacturing methods (pre 1970), the rim thickness disparity was identifying poorly made cartridges in general.

The above method applies to all cartridges. With the best RWS and sometimes, the best Lapua and Eley cartirdges, consistency is so good, that there is no difference notable.

For testing the cartridges IN the gun, the ammunition DOES need to be matched to the gun for best accuracy. The reason primarily is barrel vibration pattern, which really is very important for all free pistols. For selecting cartridges, the gun must NOT be clamped on the barrel, because that changes the vibration pattern. Some feel it must be done handheld to duplicate what occurs in actual firing, but a pistol rest can help reduce the effect of hand tremor, if that is a problem. Some groups, such as a few in Europe, further insist that the "rest" must duplicate the geometry and mass distribution and head position of the human and his grip on the gun, to take into account coupling effects or effects of the grip or stock on aim.

Some factories test the guns with the barrel clamped, because it suppresses barrel vibration when their 100 kg clamps are used, and gives a falsely high degree of accuracy.

This also is the reason that in some free pistols (rarely), the HV ammunition is more accurate than the SV ammunition: the different vibration pattern produced, even though the muzzle blast effect is adverse. Also, the vibration pattern affects not just the barrel, but the entire gun. The feedback or interaction between the barrel vibration and that of the rest of the gun is significant.

Once an optimal ammunition is found, if the pistol has auxilliary weights (for example, some free pistols, the GSP, 208-215 series Hammerli guns, etc) , these can be adjusted to tune the feedback dampening vibration to improve accuracy further. An example is the Steyr system. This does not work well with the "air weight" system, but does work with any weight that is firmly attached to the gun and mechanically linked to the barrel. The TOZ35 add-on front piece that couples the metal front end to the barrel also can be used in that way.

As to chamber fit, in general the tighter the chamber fit, the more consistent the firing due to less gas loss. However, the tight fit can create a problem in extraction. This is an area of compromise. The tighter the fit, the less gas loss and more consistent will be the gas loss until full seal occurs. Remember, in a rim fire cartridge, the seal occurs just forward of the rim area, rather than at mid cartridge as in the rimless cartridges. If the cartridges stick, the inner part of the chamber can be coated with MoS2, or one of the organic antitstick agents, as can the cartridge casing. Regarding the latter, lubrication will not affect the seal IF the coating is in the forward 3/4 of the cartridge. The seal is at the rear 1/5 of the cartridge just forward of the rim. MoS2 however can affect the seal IF it is in that most rearward part of the breech area.

Of course, when evaluating what is good and what is bad, desired accuracy is all a matter of what one desires. For some, all 50 or 100 shots in the 10 ring is fine. For others, the objective is all rounds contained within a 6 or 7mm circle at 50M.

Aim:

As to the aim, there are basically two methods, one the static, and one the dynamic method (firing while the gun is moving downward to the target point). In FP shooting, the dynamic may work better as muscle fatigue is less. The dynamic method shooting with the gun moving) takes a little practice to learn, but with the FP, the learning is easiest as the movement of the gun is disturbed so little by pulling the trigger. The same method can be used with other guns as well, but the heavier the trigger pull, the more difficult this method becomes.


The dynamic method also reduces the effects of hand and arm tremor. If using the static method, do NOT lock the arms, but leave them slightly flexed at the elbows to reduce tremor. Also it may be necessary to learn to "time" any tremor present.

The inverse dynamic approach, of raising the gun and shooting as the gun rises, also can be used. The advantage of that is clearer view of the target point, and better ability of the brain to time the movement of the gun. Also remember to focus NOT on the overall target, but on a specific 2x2mm spot of the target as your aimpoint.

The perception of drawing a line to the target by the dynamic method is a perception only. The actual mechanism is that the brain and optic system are extremely good in timing and advance targeting of moving objects, physiologically called "anticipation" targeting. This accuracy is so good, even in lowly humans compared to birds or cats, that the timing and targeting of the anticipation method can be better than the static method.

Muscle tremor primarily is a static phenomenon, that is suppressed partially or completely during movement. As a result, the moving gun method avoids or at least markedly reduces the error from tremor. The brain also is more adept (hard wired) for advance or anticipation targeting, than it is for timing tremor and adjusting the aim to compensate for that.

With a free pistol the trigger pull should be light enough that you do not actually pull the trigger consciously to fire the gun. It should fire as soon as you think about firing. This relates to the details of brain control of motor movement more than anything else, which are a 2 stage process with dual circuits that can override one another.

In the end, whether the static or dynamic method is better depends in part on the individual shooter, and how their brain works (or malfunctions).

To further confuse the situation, rarely one comes across an individual whose accuracy consistently is better than should be possible with the gun and ammunition used. Some of these individuals accomplish this by remembering variation the gun has with each shot in the sequence, and adjusting for it. However, that doesn't explain the whole picture, and other things must be talking place, which are pretty hard to understand.

Posted: Thu Jan 10, 2013 5:29 pm
by Rover
Love this "real" stuff. I found the rim thickness comments especially interesting.

I'd like to see more of this and less BS.

Posted: Thu Jan 10, 2013 6:50 pm
by Gnr527
Speaking as a two month pistol tyro I think it is brilliant - particularly the 'aim' information - discusses a lot of the questions rattling around my head.

Thanks

John

Re: Ammuniton accuracy. free pistol, handgun, rifle

Posted: Fri Jan 11, 2013 12:55 am
by jliston48
J wrote:Some very interesting comments ...
INTERESTING to say the least!

I think that it borders on the irresponsible to print information such as:
J wrote:The inverse dynamic approach, of raising the gun and shooting as the gun rises, also can be used. The advantage of that is clearer view of the target point, and better ability of the brain to time the movement of the gun. Also remember to focus NOT on the overall target, but on a specific 2x2mm spot of the target as your aimpoint.
when new shooters are trying to make sense of the basics of pistol shooting.

I have never heard anything like this in my 40+ years of competitive pistol shooting. There is NOTHING in this above statement that is pertinent to Olympic Pistol shooting (the topic of this forum). I would not even attempt to go through the exercise of trying to focus on a 2mm x 2mm spot on my 50-metre target. For one, I could not see it, secondly, it would encourage "snatching" the trigger if you could see it and third, it destroys the whole concept of area aiming that has an excellent theoretical basis.

Posted: Fri Jan 11, 2013 2:57 am
by RobStubbs
Looks to me like the OP has plagiarised someone elses 'work' without any references...

Most of the section on 'aim' sounds like garbage and is best ignored (IMHO).

Rob.

Posted: Fri Jan 11, 2013 6:01 am
by Gnr527
Coming up into aim, down onto aim, attempted steady aim and reducing tremor are just several of the aspects of air pistol shooting bothering me at present.

Viewing some championship videos indicate examples of each and my searching and reading has not been as helpful as I would wish.

The OP's post gave me grist for the mill - it would be nice to see some reasoned responses.

I have found a lot of good helpful information on this site.

Thanks

John

Area Aiming

Posted: Fri Jan 11, 2013 9:54 am
by J
A summary of the theoretical basis for the "concept of area aiming that has an excellent theoretical basis" would be appreciated. Underlying equations appreciated if available, but not essential.

Except for nuclear weapons and quantum singularity devices, I'm not so clear on the theoretical basis.

As to use of the material, usually plagarism implies without permission. That is not the situation. The permission was granted by the individuals and organizations only if the sources were not cited in the information release. The published background data on dynamic vs static aiming is extensive, most recently summarized in a 2 volume DARPA-Air Force and othe military agencies study and a related 4 volume data compendium summary from the 1980s, Human Capabilities Engineering. These data and results then were used in Navy contract work in the late 1990s.

If anyone wants to test the methods, the area vs. point aim approach can be tested with just 20-50 rounds. It takes a bit longer to try out the dynamic vs static aiming, but 50 rounds with the "new" method (whichever it is for the shooter) will be enough to give an indication of whether it will help or not. As mentioned above, there is individual variation in whom it helps.

Since the original comments came from sources that in general, do not compete in an target shooting but only use the same guns for other purposes, it may well be that "There is NOTHING in this above statement that is pertinent to Olympic Pistol shooting (the topic of this forum)". If so, perhaps the moderators would want to just delete this entire forum. If they do not, one clarification: the dynamic method does NOT necessarily involve moving the arm. In that method, usually the movement is limited to the wrist, for more precise control. It can be done with the forearm or entire arm, particularly if wrist arthritis or such is present, but that is not the usual method.

Another issue raised in some of the comments, of how to aim at a target one can not see, is a very cogent and real issue for the people from whom these comments originated, but probably not one for this forum even if it extends beyond Olympic shooting.

Other comments raise some very specific issues regarding vibration patterns in guns and their effects. Of primary interest to automotive and aircraft designers in this day and age rather than marksmen, perhaps this might be a useful discussion later, separate from this one.

Posted: Fri Jan 11, 2013 10:09 am
by Greg Derr
Real world or theory? Most of the OP points have some vague merit, but they are more based on theory and perception than reality.

Ammo testing can be grossly overdone, but it is needed. If not for the practical( yes this ammo groups well) then for the mental aspects (Is my ammo the cause of my failures) Clamping the barrels is just the easiest method since there are many types of FP and AP designs and both have very little physical support structure to clamp them on, second barrel vibration is a relatively shot barrel is not a cause for major bullet deflection.

The aiming stuff is BS and should be ignored as someone said.

Energy is best put into training, both mental and physical as oppossed to the theoretical.

sorry for any mispellings today.

Posted: Sat Jan 12, 2013 1:54 am
by jliston48
If you're expecting some high-level theoretical explanation of the basics of sighting a pistol, you're in the wrong place. The basics of ISSF pistol shooting are not that difficult to understand. The theory I refer to is that which has served beginning and champion shooters well for many years.

Once the theory is understood, the greatest component of gaining mastery is the many hours of practice.

The theoretical basis for area aiming is based on the fact that a shooter can not hold the sights perfectly still so to attempt to aim at a particular point on a target is impossible.

The next best thing FOR A BEGINNER is to try to limit the movement of the sight picture (the aligned front and rear sights) within an area.

For a beginner, this area should be about the size of an 8-ring on a 25m precision target or on an air pistol target. The problem with this is that is is often not easy to align black sights on the black part of the target.

So, if we generate an 8-ring diameter area below the black, it would be a circle drawn between the 1-ring and the 6/7-ring in the white part of the target. Of course, sights will need to be adjusted so that any shot fired in this area will strike the target within the 8-ring.

This allows the beginning shooter to try to keep his/her sights aligned and moving in this area while squeezing the trigger until the shot breaks. It also provides a basis for teaching shooters how to "call their shots" so they are able to recall where the sights were when the shot broke and compare that with where the shot actually hit the target. (Calling shots is a higher order skill but the best time to learn it is at the beginning of the training program.)

As the shooter gains more skill in restricting the movement of the pistol, s/he will be able to reduce the aiming area. By this time, the shooter will also determine where the best place is for the area to suit him/herself.

This is also about when they can decide (after many shots fired) whether they are more comfortable settling into the aiming area from above, below or wherever.

A final note here is that the focus of the eye cannot be simultaneously on the rear sight, the front sight and the target so the eye should be focused on the front sight. The target will be blurred and that is where the area aiming also helps - keep the top of the front sight aligned with a slightly blurred rear sight within a very blurred aiming area below the black.

This can be practised during dry firing or live firing. Many top shooters and champions use dry firing more often than live firing. Live firing is used to affirm that the technique is correct. But for beginners, pistol shooting is all about firing shots so go out there and fire lots - but try to do it properly.

Books that support this are: "Competitive Pistol Shooting" by Dr Laslo Antal, "The Target Gun Book of Pistol Coaching" by John Chandler and also "Competitive Shooting Techniques" by A A Yur'yev. All are old books but the basics have not changed. There is another book by Laslo Antal and Ragnar Skanaker (now there's a wealth of knowledge!)

The other ergonomic elements to become familiar with in addition to Sight Alignment are: Stance, Position, Grip, Breath Control and Trigger Control - all of these covered in the above books.

Posted: Sat Jan 12, 2013 5:37 am
by Gnr527
Thanks for all the foregoing -

From my point of view, I do practice as directed but hope discussions like this thread will save a lot of unproductive practice.

Much appreciated.

John

Theory, hypothesis, urban and folk legend

Posted: Sat Jan 12, 2013 10:06 am
by J
Thanks for the explanation of "theory". I had assumed the term was being used in the scientific or engineering connotation. The concepts listed are very interesting, in part because they are quite contrary to the data and resultant theories and formulations from studies on human neurophysiology, target acquisition, target tracking, and weapons activation by humans in the engineering and scientific studies mentioned above.

As mentioned, the outline I'd provided above derives from development and use of weaponry for purposes other than sports competition. The thought was that the methods might be useful, IF only accuracy of the gun and accuracy under psychological stress or physical fatigue were in question. I realized that the "setting" was different, but didn't realize that the concept of what was a theory and how it could be proven also would differ. Clarification of that distinction is appreciated.

If the data and (scientific or engineering) theories in the technical sense are not of use to target shooters, my apology for starting this line of discussion. Also, my apology for offering the guns to USA target shoooters as they become surplused from the other uses.

Regarding unproductive practice, as mentioned above, which method of aim and targeting is best for the individual can be defined in 10 rounds for the point of aim options, and within 30 rounds for the method of gun aim (static vs dynamic). That is somewhere between 10 seconds and 3 minutes of practice time, depending on the shooter.

Fortunately, no one has asked about methods for shooting at targets one can not see, or techniques and methods that will image both the gun sight and the distant target at the same time.

I really appreciate all the comments, especially those that note my postings have no place in discussions of olympic competition or have no basis beyond pure speculation. Personally, I always appreciate insights from those with far fewer years of experience than I have.

One thing that had puzzled me, is why the "standard" of accuracy, defined by the target itself, has not changed much since the first Olympiad in 1896. There have been changes requiring greater accuracy, but they are not huge, with none of major significance since the 1930s. This really odd in a "technology based" field. Usually the standards become much higher and tighter each decade, if not every few years.

The comments posted, and the reasons for the shift in handgun gun preferences in the last few years explains much of this.

The references; horizontal tracking

Posted: Sun Jan 13, 2013 5:11 pm
by J
A few have asked for the specific references for the technical theory and underlying data mentioned above. My apology for my error in the title. The correct titles for the fundamental references are Handbook of Perception and Human Performance (2 volumes) and Engineering Data Compendium: Human Perception and Performance (4 volumes). These are the non-classified, non-proprietary publicly released items from DARPA and the Air Force, as well as other US military agencies.

Some have asked about dynamic tracing and aim in the horizontal plane. This of course is used when the target is a moving object. However, due to the arm drift due to gravity, it is more difficult to learn, than the vertical dynamic aim method. Circular dynamic aim, where the gun is moved in a spiral or arc, probably is something cats and birds can do with ease, but humans find it much more difficult.

Re: Theory, hypothesis, urban and folk legend

Posted: Mon Jan 14, 2013 3:16 am
by RobStubbs
J wrote:<snip>One thing that had puzzled me, is why the "standard" of accuracy, defined by the target itself, has not changed much since the first Olympiad in 1896. There have been changes requiring greater accuracy, but they are not huge, with none of major significance since the 1930s. This really odd in a "technology based" field. Usually the standards become much higher and tighter each decade, if not every few years.

The comments posted, and the reasons for the shift in handgun gun preferences in the last few years explains much of this.
Pistol shooting is not really a technology based sport. The most important aspect is the shooter and evolution is a slow process. Targets have however changed but not very much, in precision events. I would suggest though there is no need to change until people are shooting scores like they are in the rifle disciplines (air and prone). Until then there's enough room to pick the best 8 shooters for the final.

Rob.

Posted: Thu Jan 17, 2013 2:38 am
by John C
I, for one, really enjoyed this thread. I think the ideas put forth are intriguing, even if I don't necessarily agree with them. I think discussing new ideas can only strengthen the sport.

-John