Mr. EISENBERG. Can you characterize those, or explain them in lay terms?
Mr. SIMMONS. Well, against a shorter target, the probability is still
almost 0.7, which is a relatively high value. The effective-range
increase is beginning to show, however, because at 270 feet the value
of 0.4 tends to be small.
Mr. EISENBERG. Does 0.4 mean you have 4 chances in 10 of hitting?
Mr. SIMMONS. Yes.
Now, our assumption throughout all of this is that the actual target
was probably not either a small--the small area, but tending to be a
larger area, as indicated by the crosshairs in these targets which we
placed at this point.
Mr. EISENBERG. Now, you have given us probabilities of hit with three
variations of aiming error. You have selected these three variations in
what manner, Mr. Simmons?
Mr. SIMMONS. These were actually the three values which were
demonstrated in the experiment.
Mr. EISENBERG. But each of those values is associated with one target?
Mr. SIMMONS. Yes.
Mr. EISENBERG. However, you have applied them to all three targets?
Mr. SIMMONS. Yes.
Mr. EISENBERG. Did you have a special reason for doing that?
Mr. SIMMONS. No. We are victims of habit, and we tend to provide such
information in parametric form.
Mr. EISENBERG. Now, Mr. Simmons, of course the assassin's aiming error
must be unknown. But do you have any opinion concerning the probable
aiming error of an assassin using this weapon against the aiming error
displayed by the three riflemen you employed?
Mr. SIMMONS. Well, it looks like to achieve hits as indicated, the
accuracy, overall accuracy of the three rounds would have to be of the
order of 1.2 mils. And this is really not a small number as far as
marksmanship goes. There have been many exercises in which we have been
involved where the aiming error turns out to be much smaller, smaller
than this. And in match competition, of course, the numbers actually
turn out to be--the total aiming error turns out to be about equal to
the round-to-round dispersion.
Mr. EISENBERG. When you make the reference to many exercises, are you
referring to exercises solely with skilled riflemen?
Mr. SIMMONS. If we have skilled riflemen, the values for aiming error
tend to be of the order of 1 mil. As a matter of fact, to qualify as
expert on Army rifle courses, about a 1 mil aiming error is required--a
standard deviation of 1 mil.
Mr. EISENBERG. Is that with a rest or without a rest?
Mr. SIMMONS. This would be without a rest. This would be the actual
aiming error from the fixed position, firing range.
Mr. EISENBERG. And is this with open or telescopic sights?
Mr. SIMMONS. This would be with the peepsight on the conventional rifle.
Mr. EISENBERG. Have you exercises which you feel would be applicable to
the assassination--that is, exercises conducted with--under noncombat
conditions, with a telescopic sight and a rest?
Mr. SIMMONS. The only experience that we have with the telescopic sight
with which I am familiar is the exercise using this weapon. There have
been experiments made using telescopic sights, but these are of limited
interest militarily.
Mr. EISENBERG. In your opinion, what effect does the introduction of a
rest and telescopic sight have on probable aiming error?
Mr. SIMMONS. From a position where the movement of the weapon is not
great, and where the target is slowly moving, the fixed position on the
telescope should enhance the probability of a hit.
Mr. EISENBERG. Do you think a marksman who is less than a highly
skilled marksman under those conditions would be able to shoot in the
range of 1.2-mil aiming error?
Mr. SIMMONS. Obviously considerable experience would have to be
in one's background to do so. And with this weapon, I think also
considerable experience with this weapon, because of the amount of
effort required to work the bolt.
Mr. EISENBERG. Would do what? You mean would improve the accuracy?
Mr. SIMMONS. Yes. In our experiments, the pressure to open the bolt was
so great that we tended to move the rifle off the target, whereas with
greater proficiency this might not have occurred.
Mr. EISENBERG. Could this experience in operating the bolt be achieved
in dry practice, Mr. Simmons?
Mr. SIMMONS. Yes; it could be, if sufficient practice were used. There
is some indication of the magnitude of change with one of our shooters
who in his second attempt fired three-tenths of a second less time than
he did in the first.
Mr. EISENBERG. Mr. Simmons, has data been compiled showing the effect
of the time taken between shots on the accuracy of the shots?
Mr. SIMMONS. There have been experiments run where aiming error has
been measured as a function of the time one has to aim.
Mr. EISENBERG. Do those experiments show that aiming error is directly
proportionate to the length of time one has to aim?
Mr. SIMMONS. Not directly proportionate, but aiming error decreases
as time increases. But once you get to the area of about 4 seconds in
time, then there is very small decrease in aiming error for increase in
time.
Mr. EISENBERG. Translating that to this weapon, does that mean that
taking more than 8 seconds between three shots should not appreciably
affect the degree of accuracy?
Mr. SIMMONS. The 8 seconds I was referring to is between shots.
Mr. EISENBERG. You said 4 seconds, I thought.
Mr. SIMMONS. I beg your pardon.
Mr. EISENBERG. And I was saying, if you took 4 seconds between the
first and second, and 4 seconds between the second and third, for a
total of 8 seconds, on the basis of this data would that mean after
8 seconds you would not be substantially increasing your accuracy by
taking more time?
Mr. SIMMONS. That is correct.
Mr. EISENBERG. Approximately how many bullets did you fire in the
course of your tests?
Mr. SIMMONS. We fired 47 bullets.
Mr. EISENBERG. Did you have any misfires?
Mr. SIMMONS. None.
Mr. EISENBERG. Were you aware when you performed your tests of the
conclusions of any other body concerning the accuracy of this weapon?
Mr. SIMMONS. No; we were not.
Mr. EISENBERG. Are you aware of such conclusions at this point?
Mr. SIMMONS. No; I am not.
Mr. EISENBERG. Mr. Chairman?
Mr. McCLOY. You said that these riflemen, or one or two of them at
least, had the rank of master. What is that?
Mr. SIMMONS. I again fall back on my comment earlier that I am not
a shooter myself. A master is one of the ratings given to highly
qualified riflemen by the National Rifle Association. These men have
all participated in national match competitions in the National Rifle
Association.
Mr. McCLOY. Is that a higher grade than sharpshooter in the Army?
Mr. SIMMONS. There is really no comparison between the rating of master
in the NRA and the rating of sharpshooter in the Army.
Mr. EISENBERG. I am not sure whether or not you answered this question,
but do you feel that if the target was moving, rather than having the
rifleman move, there would have been a difference in aiming error,
increased or decreased aiming error--if the target was moving 5 to 10
miles an hour?
Mr. SIMMONS. I think the movement of the target in this case would have
practically no effect on the accuracy of fire, because from the map we
are led to believe that the movement was primarily away from the firer,
so that the back of the President was fully exposed to the rifleman at
all times.
Mr. EISENBERG. Could you explain your reference to a map? You have made
several references to that.
Mr. SIMMONS. I refer to the survey plat which is dated December 5, 1963.
Mr. EISENBERG. And how were you supplied with that?
Mr. SIMMONS. To the best of my knowledge, you gave it to one of the
employees in my office.
Mr. EISENBERG. Mr. Chairman, this is a plat made by a licensed surveyor
of the area immediately adjoining the Texas School Book Depository.
I would like to introduce it into evidence solely to show the basis
which Mr. Simmons was using in his test, and not for the truth of the
measurements which are shown in here.
Mr. McCLOY. It may be received.
Mr. EISENBERG. That would be Commission 585.
(The document referred to was marked Commission Exhibit No. 585 and
received in evidence.)
Mr. EISENBERG. I have no further questions.
Mr. McCLOY. I have no further questions.
Mr. EISENBERG. Is there anything you would like to add to your
testimony?
Mr. SIMMONS. I think not.
Mr. EISENBERG. I wonder whether we could have a copy of your table?
Mr. SIMMONS. Yes.
Mr. McCLOY. From your experience, Mr. Simmons, do you feel that with
a man who had been in the Marine Corps, with the rifle instruction he
had there, using this rifle, and what you know of the shots that killed
the President--do you think he was an extraordinarily good shot, do you
think he was just shooting in accordance with what might be taken to be
the skill that service in the Marine Corps would give him?
Mr. SIMMONS. Well, in order to achieve three hits, it would not be
required that a man be an exceptional shot. A proficient man with this
weapon, yes. But I think with the opportunity to use the weapon and to
get familiar with it, we could probably have the results reproduced by
more than one firer.
Mr. McCLOY. I think that is all.
Mr. EISENBERG. One thing, Mr. Chairman. May I have this admitted as
586, this table which Mr. Simmons prepared, from which he was giving
testimony earlier? This is "Table I, Hit Probability as a Function of
Range and Aiming Error."
Mr. McCLOY. It may be admitted.
(The table referred to was marked Commission Exhibit No. 586 and
received in evidence.)
Mr. EISENBERG. When you say proficiency with this weapon, Mr. Simmons,
could you go into detail as to what you mean--do you mean, accuracy
with this weapon, or familiarity with the weapon?
Mr. SIMMONS. I mean familiarity basically with two things. One is the
action of the bolt itself, and the force required to open it; and two,
the action of the trigger, which is a two-stage trigger.
Mr. EISENBERG. Can familiarity with the trigger and with the bolt be
acquired in dry practice?
Mr. SIMMONS. Familiarity with the bolt can, probably as well as during
live firing. But familiarity with the trigger would best be achieved
with some firing.
Mr. EISENBERG. Why is there this difference between familiarity with
the bolt and familiarity with the trigger in dry firing?
Mr. SIMMONS. There tends to be a reaction between the firer and the
weapon at the time the weapon is fired, due to the recoil impulse. And
I do not believe the action of the bolt going home would sufficiently
simulate the action of the recoil of the weapon.
Mr. EISENBERG. One further question.
Looking at the figures for aiming error, as discounted by
round-to-round dispersion, how would you characterize the actual
performance of men with this rifle--that is, not the accuracy of the
weapon, but the accuracy of man and weapon.
Mr. SIMMONS. I am not sure I understand your question.
Mr. EISENBERG. Do you feel on the basis of the aiming error, discounted
for round-to-round dispersion or including it, that this weapon is an
easy one with which to be accurate, or a difficult one?
Mr. SIMMONS. It appears to be relatively conventional in that regard,
I assume. The telescope helps in the accuracy against a target which
is well displayed, as was the case here. And the weapon is reasonably
conventional. So that I think it would not be significantly different
from any other weapon.
Mr. McCLOY. If you were having a dry run with this, you could certainly
make yourself used to the drag in the trigger without discharging the
rifle, could you not?
Mr. SIMMONS. Yes. But there are two stages to the trigger. Our riflemen
were all used to a trigger with a constant pull. When the slack was
taken up, then they expected the round to fire. But actually when the
slack is taken up, you tend to have a hair trigger here, which requires
a bit of getting used to.
Mr. McCLOY. This does not have a hair trigger after the slack is taken
up?
Mr. SIMMONS. This tends to have the hair trigger as soon as you move it
after the slack is taken up. You achieve or you feel greater resistance
to the movement of the trigger, and then ordinarily you would expect
the weapon to have fired, and in this case then as you move it to
overcome that, it fires immediately. And our firers were moving the
shoulder into the weapon.
Mr. McCLOY. I have no further questions.
Mr. EISENBERG. That is all.
Mr. McCLOY. Thank you very much. You have been very helpful.
We shall recess now until 9 o'clock tomorrow morning.
(Whereupon, at 5:25 p.m., the President's Commission recessed.)
_Wednesday, April 1, 1964_