Trajectory of a 38 Special

[ryan richards]

Hi Guys,

I've got an easy one for the CBOs (Cast Boolit Oracles).

I live on my farm in the Amazon so I've got plenty of room to shoot. However, I don't want any accidents - safety first. I´ll use an earthen berm for my shooting backstop.

Question N° 1. If the berm is missed, how far is a 38 Special (158gr. SWC) going to travel before it hits the ground assuming the boolit is fired parallel to the ground? I read on internet that this boolit will drop 8.4" in 100 yds. from a 4" barrel.

Question N° 2: How far will the same boolit travel if it is aimed upwards by a 45° angle?

I just want to know the safety distance if a stray boolit and someone cutting through my property down range happen to meet.

Thanks for your time and interest.

Ryan

[Echo]

Not sure about the distances, but - It seems that the Ordinance guys did some tests and found that bullets would NOT go maximum range when fired at a 45 degree angle. Max range was found to be when fired in the vicinity of 30 degrees, due to aerodynamic effect of slowing the projectile.

A guess for the .38 Special, fired horizontally from a height of 66 inches (5 1/2 feet) would be between 1/4 and 1/2 mile, and fired at max range - another guess - maybe 1 1/2 miles. What say, guys? Are my guesses close?

[NSP64]

Howdy, Welcome to the site. Assumeing your 38 special 158gr SWC is traveling 1000 fps with a zero of 25yrds it will drop 95 inches by 225yrds. This is a best guess using general info. style of boolit and speed will change some things. Are you casting your own?

[selmerfan]

Well, let's apply some physics to it. If one fires the boolit perfectly parallel to a flat surface, it will travel for the same amount of time as a boolit dropped from the same height at the same instant. So...if you time how long it takes for a dropped boolit to hit from a known height, let's say 5 feet, then you can figure out how far it will travel if the velocity of the projectile is known. Let's say that the boolit takes 1/2 of a second to drop 5 feet (I have know I idea how long this would take, 1/2 second is totally arbitrary) and you're shooting a 158 gr. projectile at let's say 800 fps (again, arbitrary number) With this projectile fired parallel to the ground and these particular figures, the boolit would travel 400 feet before hitting the ground. This is because it takes 1/2 second for the boolit to fall 5 feet, and the boolit is moving at 800 fps. Therefore, 1/2 second of travel would yield 400 feet of travel. Of course, these figures would only be realistic in a complete vaccuum! Air resistance, friction, air density and temperature are all variables that make this equation null and void, but I GUARANTEE with these numbers that the boolit would travel LESS than 400 feet before the boolit strikes the ground. Simple high school physics. :)
Selmerfan

[ryan richards]

Hi Guys,

Thanks for your replies.
Yes, it would be a cast bullet from w-ws. Store bought boolits cost more than $1 apiece down here. I would have flunked physics in high school if I took it, good to have a trajectory Oracle on board.

[Bass Ackward]

However, I don't want any accidents - safety first.

Question N° 1. If the berm is missed, how far is a 38 Special (158gr. SWC) going to travel before it hits the ground assuming the boolit is fired parallel to the ground? I read on internet that this boolit will drop 8.4" in 100 yds. from a 4" barrel.

Question N° 2: How far will the same boolit travel if it is aimed upwards by a 45° angle?




Ryan,

Good attitude on safety.

Question 1: This becomes confusing. Because a slug fired level is likely to hit the ground at a slight enough angle, with lead, to richocett on out farther at what amounts to being incalculable. One can not always assume that a richocett continues straight. Your background should always be chosen for a shot as this is the only way to attempt safely.

Question 2: About 2700 yards is max under any angle scenario that I can come up with. Velocity at the end is only around 29 fps, so richocett is minimal as is serious penetration.

Scenario number one is the most problematic.

[405]

ryan,
Amazon??? assuming it's flat :mrgreen: that'll simplify things some. As stated already, a launch angle of something around 30 degrees above horizon usually yields max range.

38 wadcutters average very low ballistic coefficients. About .038 I think. The 38 semi- wadcutter (SWC) is a little better with a BC of maybe .150

Here's a link to a very good inter-active site that allows playing with all kinds of variables on bullet trajectories. Just let it load java applet and a screen should come up. On the left margin are some options. Click on "define own bullet"
That will open another option that allows you to add ballistic coefficient and bullet weight.
Then it's just a matter of playing around with whatever sight set up, velocity, zero ranges, max ranges, etc. you select.


http://web.archive.org/web/20060206153811/http://www.norma.cc/htm_files/javapagee.htm

[ryan richards]

Hi CBOs,

Once again you have amazed me with your valuable information. Especially, the website given by 402. The only thing more amazing than the site 402 recommended is HOW 402 found it!

Thanks, Ryan

[38 Super Auto]

My calcs tell me that the bullet will drop five feet in about 0.55 secs. So, if you launch it parallel to the earth on flat terrain from a height of five feet at muzzle velocity=1000fps, it should hit the earth before it has traveled 500 feet. But it's going to bounce and travel a little further right?

[MtGun44]

I have a friend that lives out in western Kansas. He has informal rifle shoots
out on his land. He says "Don't shoot the trailer or each other, otherwise no
limits. You CANNOT get a bullet off my land. " He has a loading trailer out at
his "range" which is featureless flat land.

Neat. Wish I had that kind of "range". No need to calculate anything. [smilie=1:

Bill

[redgum]

Good onya Ryan,
Maybe this link will be of use in calculating your trajectory
http://www.handloads.com/calc/index.html

[Ricochet]

Supposedly the first two cars in Kansas ran into each other. (Bet they were racing.)

[KCSO]

If you have a berm the #1 case bullet will hit the berm, right. On the #2 case they will go about 1/2 mile. Nice to have a LOOONG range occasionaly.

[felix]

The first car wreck in MO was in Springfield, between two cars that couldn't decide on who was to stop at an intersection. I remember reading that in high school while doing a MO history report. ... felix

[targetshootr]

Even more off topic, years ago I saw in Ripleys two old Fords were heading toward each other on a foggy night in the middle of nowhere with each driver's head out of the window to see better and, you guessed it, squish.

:shock:

[NSP64]

The first car wreck in MO was in Springfield, between two cars that couldn't decide on who was to stop at an intersection. I remember reading that in high school while doing a MO history report. ... felix

That's why it's the 'show me' state.:drinks:

[Tom Herman]

Two thumbs up on your calculations!
Here's how he got there: S= 1/2 gt squared, where:

S= distance dropped in feet.
g= force of gravity (32 feet per second)
t= time

We know S (5 feet approx), and g (32 FPS), so we can rearrange the formula to solve for t:

The square root of 2S/g=t, or square root of 10/32 = t, or .559 seconds...

38 auto gets the gold star for mathematical excellence!
You can use this formula to roughly figure drop for short distances.
Of course, it gets much more complicated for longer distances because you have to take into consideration bullet aerodynamics, and the slowing of the projectile.

Happy Shootin'! -Tom



My calcs tell me that the bullet will drop five feet in about 0.55 secs. So, if you launch it parallel to the earth on flat terrain from a height of five feet at muzzle velocity=1000fps, it should hit the earth before it has traveled 500 feet. But it's going to bounce and travel a little further right?

[rufracer]

realguns.com also has a good free exterior ballistics calculator. You do have to sign up to use it though.

[35remington]

Try this link; it's mainly for rifle bullets but has a few pistol bullets listed. I used the Speer 158 grain flatpoint, the BC is "close enough" and you can develop your own BC from input you know or from the supplied tables:

http://www.eskimo.com/~jbm/calculations/maxdist/maxdist.html

Anyway, at 900 fps and a reasonable 30 plus degree angle we're talking in the vicinity of 1750 yards maximum range at standard atmospheric conditions, 1100 ft altitude. I assumed a BC of .150 for additional calculations, which apply to these figures.

My terminal velocity was in the vicinity of 290 fps.

[Tom Myers]

A Lyman 358429 Semi Wadcutter bullet fired from a 38 Special over 5 grains of Unique will have a muzzle velocity of around 850 fps. The bullet, when fired paralell to the ground at a height of 65 inches, would strike the ground at 143 yards down range with a velocity of 773 fps.

The same bullet, when fired at an initial angle of 35.5 degrees, will reach maximum height at 1272 yards downrange and will reach a maximum distance of 1933 yards down range, striking at an angle of 69.7 degrees and at a velocity of 408 fps.

That's my story and I'm stickin' to it.

Tom Myers
Precision Ballistics and Records. (http://www.tmtpages.com)

P.S. At about 1500 yards downrange, after the bullet has started downhill, the velocity has dropped to 261 fps and then gravity starts to overcome the air resistance and continues to accelerate the bullet until it reaches the velocity of 408 fps when it hits the ground.

[wmitty]

it's interesting that the b.c. of the boolet is so low that it will actually accelerate during its flight. I would have thought all projectiles would continuously decelerate up to an initial flight angle of something like 45 degrees.

walter m.

[35remington]

All bullets fired from handheld firearms decelerate once they leave the muzzle and proceed on their journey, assuming, of course, that it does not "top out" on its upward path to a very low velocity, and then accelerates modestly as it falls back to earth.

"it's interesting that the b.c. of the boolet is so low that it will actually accelerate during its flight"

Haven't heard of that occuring past the end of the barrel. The more like a whiffleball the bullet is, the faster it decelerates.

[wills]

http://files.dnr.state.mn.us/outdoor_activities/shooting_ranges/outdoor_shooting_best_practices.pdf

this might help some, on range design, give it time it opens as a pdf

and another ballisitcs calculator

http://www.handloads.com/calc/

[Tom Myers]

it's interesting that the b.c. of the boolet is so low that it will actually accelerate during its flight. I would have thought all projectiles would continuously decelerate up to an initial flight angle of something like 45 degrees.

walter m.

Walter,

The bullet does not begin to accelerate until it has begun the downhill leg of the trajectory and by then it has decelerated to the point that there is comparatively little air resistance. The acceleration due to gravity is more than the air restance so the bullet begins to pick up speed. Depending upon the ballistic coefficient and the attitude of the bullet, if it has been fired at a steep enough angle and gained enough altitude it will continue to accelerate on the downhill leg of the trajectory untill the air resistance equals the acceleration of gravity then from that point on it will continue it's journey without any more change in velocity.

Tom Myers
Precision Ballistics and Records (http://www.tmtpages.com)

[missionary5155]

Hello Good morning... PM sent. I live in Arequipa, Peru Neighbor !

[gon2shoot]

I can't hit anything with a 38 snubbie past 200 yd. :roll:

[ryan richards]

Hi guys,

I would have never guessed that such a wealth of information would result from such a couple simple questions.

Let's use the last post by Tom Myers for the next question.

We all can assume that being hit with a "Lyman 358429 Semi Wadcutter bullet fired from a 38 Special over 5 grains of Unique with a muzzle velocity of around 850 fps." will do you some serious damage if you are hit in the chest at 25 yards.

What damage will that same bullet do to you if you were hit in the chest at 1500 yards downrange at a velocity of 408 fps?

I am thinking about safety.

[flinchnjerk]

From the Lyman Reloading Handbook 46th edition (chart titled "How far will my gun shoot?")
The optimum angle of departure for maximum horizontal range is given as 30 degrees.
.38 Spec. 158 gr bullet (no nose profile given)
m.v. 855 fps Approx. distance in yds: 1833
m.v. 1090 fps Approx. distance in yds: 2133