Ballistic Calculator


Users Currently Browsing This Topic:
0 Members and 2 Guests are viewing this topic.

Author Topic: Ballistic Calculator  (Read 2273 times)

Online Richard Smith

  • Hero Member
  • *****
  • Posts: 3664
Re: Ballistic Calculator
« Reply #8 on: June 30, 2022, 04:16:08 PM »
According to Marina he spent at least two months preparing for the Walker shooting and you suggest he didn't practiced with the the rifle!

Any doubt that you're genuine Nutter material has now been eliminated.

 Thumb1:

I thought it was contrarians who didn't believe Marina?  Going on and on asking for "corroborating" evidence of what see observed.  LOL.  Try to be consistent.  Oswald missed Walker only because his bullet deflected off the window frame.  You can see the damage in photos.

JFK Assassination Forum

Re: Ballistic Calculator
« Reply #8 on: June 30, 2022, 04:16:08 PM »


Online Richard Smith

  • Hero Member
  • *****
  • Posts: 3664
Re: Ballistic Calculator
« Reply #9 on: June 30, 2022, 05:29:19 PM »
Based on your premise that Marina, being Oswald's own wife, would be the Nutter's preferred witness.

Perfectly consistent.

 Thumb1:

Good.  So you finally agree that Marina saw a "rifle" in the blanket and took the BY photos!  Progress.

Online Richard Smith

  • Hero Member
  • *****
  • Posts: 3664
Re: Ballistic Calculator
« Reply #10 on: June 30, 2022, 09:53:38 PM »
No, I simply pointed out that a nutjob who believe in the Walker fantasy can't put together a coherent argument.

BTW, did you work out why he only brought one round?

LOL

So you cast doubt on Marina when she says that she saw a "rifle" but then suggest in another context that it is unreasonable for someone to doubt her testimony about Oswald practicing with a rifle (something you have argued yourself).  But then suggest that others here believe in a fantasy.  And finish with the standard LOL as though you have proven something (which should be SOL in your case).   The rabbit hole beckons. 

JFK Assassination Forum

Re: Ballistic Calculator
« Reply #10 on: June 30, 2022, 09:53:38 PM »


Offline Brian Roselle

  • Jr. Member
  • **
  • Posts: 65
Re: Ballistic Calculator
« Reply #11 on: July 01, 2022, 01:31:30 AM »
Joe,

Your analysis approach looks interesting and inputs look pretty good to me. Nice job pulling it together.

I've only used a trajectory calculators briefly before and don't have much experience with them so I wondered if you are familiar enough with this trajectory calculator to have any sense on how sensitive gravitational drop distance might be to muzzle elevation?

I am actually asking this because of the first shot that missed. That is the shot I have spent some time on and I am in the camp of a pretty early missed shot that would necessitate a fairly steep muzzle elevation deviation from horizontal toward vertical, and if the bullet drop distance, relative to say a laser line of sight, is largely related to flight time (while gravity is acting), it may simply be that be the muzzle elevation doesn't have much effect.

Maybe running the calculator by changing only the muzzle elevation from 0 to -30 degrees or something would give the same drop in a given time versus the respective bore site. I suspect the calculators don't make a distinction between X (horizontal) and Y (vertical/gravity) direction of travel relative to the effective ballistic coefficient used.

Just sort of curious on these trajectory calculators. I have never done any hunting is why I never really used them, but I have done some target shooting in the past and I think I might have gotten a marksman merit badge in cub scouts, but I was told I wore pants that looked like Maggie’s drawers.

Online Charles Collins

  • Hero Member
  • *****
  • Posts: 2706
Re: Ballistic Calculator
« Reply #12 on: July 01, 2022, 02:13:57 PM »
The information provided by Joe regarding the ballistics appears to me to be to be enlightening with respect to the scope limitations when attempting to zero-in at 100-yards. There are multiple aspects to consider regarding zeroing-in the side-mounted scope. But to focus on one of them, it appears to me that if the scope was originally mounted by using the typical bore-sight method, then, elevation-wise, it should have been closely matched to the stationary iron sight’s 200-meter zero-in distance. This is due to the ballistics calculator showing only about a -0.1” impact (in elevation) from the centerline of the barrel at that distance.

Looking again at the ballistics calculator data for this rifle and ammunition, we can see that at 100-yards the impact of the bullet is 5.76” above the centerline of the barrel (bore sight line). The scope is an inexpensive relatively small (compared with a typical high-powered hunting rifle scope) scope. It is more typical of one we might put on a .22 caliber rifle and use to learn to shoot with (similar to what I had as a teenager). When reading Robert Frazier’s description and diagrams as testified to the Warren Commission, it appears to me that the adjustment necessary (5.76”) to zero-in the scope at 100-yards is close to (if not exceeding) the range of adjustment available in the mechanism of that scope. And I suggest that the description of a “defective” scope that has become common in this case, is not accurate. I believe that a more accurate description would be that the limited range of adjustment of that scope doesn’t allow it (as mounted on that rifle) to be easily zeroed-in at 100-yards.

Taking this further (and making some assumptions) it appears to me that LHO did make some detailed plans before he attempted to shoot General Walker. Also, it seems to me that if the scope on the rifle was defective and/or useless, that he would have taken it off. So, when we look at the ballistics calculator again for the distance of the shot at Walker (only ~100-feet, or 33-yards) the impact of the bullet is only about 2.5” above the centerline of the barrel (bore sight). If I am thinking about this correctly, the available range of adjustment of the scope should allow this much smaller amount (compared to the 5.76” required at 100-yards). But I could be wrong, so please feel free to correct me. So, it seems to me that it is probable that in all the careful planning that was apparently made for the Walker shooting, the distance of the shot should have been noted and estimated. And that the scope could have been zeroed-in at that distance when practice shooting the rifle. And if that is what happened, then it seems to me that (assuming normal careful handling of the rifle) when the rifle was used in Dealey Plaza that the scope was probably still at or close to that setting due to an apparent lack of time to zero-in the rifle again before the shots were taken.

Offline Bill Chapman

  • Hero Member
  • *****
  • Posts: 6436
  • 'Pristine'..yeah, sure
Re: Ballistic Calculator
« Reply #13 on: July 01, 2022, 03:22:16 PM »
The information provided by Joe regarding the ballistics appears to me to be to be enlightening with respect to the scope limitations when attempting to zero-in at 100-yards. There are multiple aspects to consider regarding zeroing-in the side-mounted scope. But to focus on one of them, it appears to me that if the scope was originally mounted by using the typical bore-sight method, then, elevation-wise, it should have been closely matched to the stationary iron sight’s 200-meter zero-in distance. This is due to the ballistics calculator showing only about a -0.1” impact (in elevation) from the centerline of the barrel at that distance.

Looking again at the ballistics calculator data for this rifle and ammunition, we can see that at 100-yards the impact of the bullet is 5.76” above the centerline of the barrel (bore sight line). The scope is an inexpensive relatively small (compared with a typical high-powered hunting rifle scope) scope. It is more typical of one we might put on a .22 caliber rifle and use to learn to shoot with (similar to what I had as a teenager). When reading Robert Frazier’s description and diagrams as testified to the Warren Commission, it appears to me that the adjustment necessary (5.76”) to zero-in the scope at 100-yards is close to (if not exceeding) the range of adjustment available in the mechanism of that scope. And I suggest that the description of a “defective” scope that has become common in this case, is not accurate. I believe that a more accurate description would be that the limited range of adjustment of that scope doesn’t allow it (as mounted on that rifle) to be easily zeroed-in at 100-yards.

Taking this further (and making some assumptions) it appears to me that LHO did make some detailed plans before he attempted to shoot General Walker. Also, it seems to me that if the scope on the rifle was defective and/or useless, that he would have taken it off. So, when we look at the ballistics calculator again for the distance of the shot at Walker (only ~100-feet, or 33-yards) the impact of the bullet is only about 2.5” above the centerline of the barrel (bore sight). If I am thinking about this correctly, the available range of adjustment of the scope should allow this much smaller amount (compared to the 5.76” required at 100-yards). But I could be wrong, so please feel free to correct me. So, it seems to me that it is probable that in all the careful planning that was apparently made for the Walker shooting, the distance of the shot should have been noted and estimated. And that the scope could have been zeroed-in at that distance when practice shooting the rifle. And if that is what happened, then it seems to me that (assuming normal careful handling of the rifle) when the rifle was used in Dealey Plaza that the scope was probably still at or close to that setting due to an apparent lack of time to zero-in the rifle again before the shots were taken.

My understanding of factory-zeroed-in-at-230m means that the sights do not have to be adjusted between 0-230m

JFK Assassination Forum

Re: Ballistic Calculator
« Reply #13 on: July 01, 2022, 03:22:16 PM »


Online Charles Collins

  • Hero Member
  • *****
  • Posts: 2706
Re: Ballistic Calculator
« Reply #14 on: July 01, 2022, 03:32:32 PM »
My understanding of factory-zeroed-in-at-230m means that the sights do not have to be adjusted between 0-230m

If you are referring to the factory iron sights on the Carcano 91-38 rifles, it is my understanding that they are fixed (non-adjustable). And according to Joe’s ballistic calculator data, impact of the bullet would be 5.76” high at 100-yards. It would be ~0.1” low at 219-yards (200 meters). So, the shooter has to compensate accordingly when shooting at an distance other than the 200 meters that he factory iron sights are made for.

Offline Bill Chapman

  • Hero Member
  • *****
  • Posts: 6436
  • 'Pristine'..yeah, sure
Re: Ballistic Calculator
« Reply #15 on: July 01, 2022, 08:46:25 PM »
If you are referring to the factory iron sights on the Carcano 91-38 rifles, it is my understanding that they are fixed (non-adjustable). And according to Joe’s ballistic calculator data, impact of the bullet would be 5.76” high at 100-yards. It would be ~0.1” low at 219-yards (200 meters). So, the shooter has to compensate accordingly when shooting at an distance other than the 200 meters that he factory iron sights are made for.

Seems to me that when one is on the battlefield trying to avoid having
to learn German eventually, one can simply point-and-shoot at a Nazi torso
without needing a personal nerd tagging along with his degree in math.

___________________________________________________________

Shooting the 6.5 X 52 mm, 7.35 x 51mm Cartridges and the Carcano Rifles,
an article by Dave Emary, Senior Ballistician of Hornady Manufacturing


____________________________________________________________

The 6.5 X 52 mm cartridge has taken a great deal of criticism as being
underpowered and anemic. From a ballistic standpoint this is a little hard
to justify. The Swedish 6.5 X 55 mm cartridge is considered an outstanding
cartridge yet it is only able to produce 100 fps more velocity with a
156-grain bullet in the M96 rifle. The 6.5 X 55 requires a maximum average
pressure of 55,000 psi and approximately 6 more grains of powder to
produce this meager gain in performance. The . 30-30 Winchester, regarded
as an adequate deer rifle and known to have killed many moose and bear
produces 2,220 fps in a 24” barrel with a 170 grain bullet. The 6.5 X 52
mm fires a bullet with a higher ballistic coefficient, at a higher
velocity, shoots flatter and has far more penetration capability than the
.30-30. From the standpoint of a service rifle cartridge the 6.5 X 52 with
its relatively low operating pressure, coupled with its modest powder
charge would result in much less barrel throat erosion and wear. This
would equate to longer barrel life and decreased operating cost. In fact,
much of what was done in the Carcano rifle/ammunition system was aimed at
long barrel life, as will be shown later. From my point of view the 6.5 X
52 is a very efficient cartridge, offering adequate performance for what
it was intended.

The only fault that one might level against the 6.5 X 52 as a military
cartridge is that it had relatively humane terminal ballistics. The very
long, blunt nosed bullet coupled with the fast twist rate of the gun
resulted in a bullet that was very stable with a very high resistance to
tumbling. The cartridge was known to have inflicted many “through and
through” wounds, just leaving a small wound channel. The bullet
typically would not tumble inside its’ target unless it encountered
something hard such as bone. When it did tumble the wounding effect is
well known.

____________________________________________________________


The original 6.5 X 52 mm Carcano design used a gain twist barrel. The gain
twist results in a very slow initial twist in the barrel progressively
getting faster until the full twist rate is attained at the muzzle. The
slow initial twist results in substantially less torque being imparted to
the bullet during the highest loading phase of the interior ballistic
cycle. This results in significantly less barrel wear in the throat. This
coupled with the very deep rifling of the barrel would result in barrels
that would have a very long wear and accuracy life. This in fact is the
case. Many M91 model rifles show signs of considerable amounts of
ammunition being fired through them, because of the crazed/frosted
condition of the bore, yet still show very strong rifling and shoot well
with the proper size bullets. The 7.35 X 51 mm Carcano rifles used a
standard fixed twist barrel. The Carcano bolt is the model of a simple,
easy to field strip bolt. It is about as fool proof as you can get for a
common soldier. The Carcano trigger has taken a considerable amount of
criticism. The trigger is basically a Mauser type two-stage trigger. In
almost all cases if you find the trigger rough or creepy simply polishing
the sear and trigger mating faces result in a very acceptable trigger for
a military rifle. For the most part I have found Carcano triggers have
less creep, are more crisp and lighter than the majority of Mauser
triggers I have encountered.

The materials used in the Carcano are excellent. These rifles were made
from special steels perfected by the Czechs, for which the Italians paid
royalties. If you have ever tried doing any work on a Carcano receiver you
will find out just how hard and tough the steel is. The Carcano has also
received a reputation as being a “weak” design. Nothing could be
further from the truth. The Italians made a small run of Carcanos early in
WW II chambered for 8 X 57 JS. The Germans rechambered some Carcanos to 8
X 57 JS late in WW II. These rifles were also proofed for this cartridge.
The CIP minimum suggested proof pressure for the 8 x 57 JS cartridge is
73,500 psi. I hardly call this a weak action.

____________________________________________________________

The Italians apparently realized that a 300-meter battle zero was a bit
impractical and with the introduction of the M38 models went to a 200
meter battle zero. This zero results in a maximum height of trajectory of
5.5” – 6.5” at a range of approximately 100 yards, depending on
barrel length. With this sight setting, by simply holding on the middle of
the torso, it would have been hard to miss the target out to about 220
meters. The Carcano’s also used a unique sight picture. The proper sight
picture for regulated sights on a Carcano is with the front sight in the
very bottom of the rear sight groove. This is how the Italian army manuals
instructed that the sights be used. Potentially, this would allow for two
battle sight settings. The normal use as mentioned above would be a 200
meter zero. Using the Mauser sighting method, the front sight level with
the rear sight, would result in a zero of 330 – 350 meters. This is
about the maximum range practical for attempting to engage a target with
iron sights. I contend with the Carcano the Italians had a very
intelligent approach for a battle rifle. The fixed sights were basically
fool proof. The Italians must have realized with the M38 models that
nearly all small arms engagements occurred inside of 200 meters. The fixed
sights with a 200 meter zero would have been fool proof for a soldier
under stress, who was probably a poor judge of distance to begin with. The
soldier would have had to do nothing but point and shoot at the middle of
his enemy for ranges out to 220 – 230 meters. How much more simple and
effective could it have been made.

____________________________________________________________

6.5 x 52 mm

The Carcano rifles are capable of outstanding accuracy. With the exception
of a military issue type load in the short carbines they are very pleasant
to shoot from a recoil standpoint. Because of the above mentioned sight
picture for the Carcano, front sight in the bottom of the rear sight
notch, it is very important to have a consistent stock- cheek weld for
consistent accuracy. It is often very helpful to use a carbide lamp or a
sight black product to blacken the sights, which improves contrast and
sight picture.

____________________________________________________________

CONCLUSION:

The 6.5 X 52 is a very useful and capable cartridge. It served well as a
military cartridge for over 80 years. The 7.35 X 51 would have been an
even more effective military cartridge than the 6.5 X 52 had its timing
been different. It is interesting to note that the .308 Winchester / 7.62
X 51 mm NATO and the 7.35 X 51 mm are nearly the same dimensions. Both the
6.5 and 7.35 cartridges are fun to shoot and properly loaded capable of
very good accuracy. The Carcano rifle is a well made rifle that is by no
means weak or poorly manufactured. They are reliable and strong rifles
that are fun to shoot and offer a tremendous variety of types and markings
for the collector. I will admit that they are a rather utilitarian rifle
as compared to some others. However, they are probably one of the most
efficient, cost effective, user friendly battle rifles produced in their
era. The rifle, ammunition combination properly loaded is capable of
accuracy that will rival the most accurate of the Mauser chamberings.

____________________________________________________________
Carcano Homepage: Italian Military Rifles and Carbines
http://personal.stevens.edu/~gliberat/carcano/



« Last Edit: July 01, 2022, 08:49:14 PM by Bill Chapman »

JFK Assassination Forum

Re: Ballistic Calculator
« Reply #15 on: July 01, 2022, 08:46:25 PM »


 

Mobile View