Which slows down faster? 22 or 45?

[Messy bear]

I set up a test to see which is has a better bc. The contenders are the 40 gr. 22 long rifle standard velocity against the Lee 255 RF 45 colt bullet. They were shot in open air at 325 yd over two cronographs to check both muzzle and downrange velocities. I will post results in a day or two.

[outdoorfan]

Sounds like fun. Looking forward to seeing the results.

[tomme boy]

Faster lighter bullets slow down faster. They do not have the mass to maintain the momentum. Been proved about 10M times and counting

[corbinace]

I hope the Chrony is behind a steel plate:bigsmyl2::kidding::brokenima

[country gent]

I have a lab radar chronograph and get numbers ( velocities) at 5 distances from every shot with it. I shoot a 535 grn postel over BP. Muzzle corrected was 1250 fps and the last 200yds was 1100 fps I believe, I'm working from memory here right now. The Lab Radar makes this testing easy and quick, with nothing but the target down range. It picks 38 cal rifle bullets up out to 200yds plus a little. I'm not sure how far it would pick up the 22lr bullet though.

[Neverhome]

I hope the Chrony is behind a steel plate:bigsmyl2::kidding::brokenima


First thing I thought too when I saw the range!

[Neverhome]

Faster lighter bullets slow down faster. They do not have the mass to maintain the momentum. Been proved about 10M times and counting

Pretty extreme oversimplification and not remotely true when discussing apples and oranges.

[outdoorfan]

I have chronographed the 22 mag (34 gr winch. Supreme) at 100 yards. It held the same muzzle energy as a 22 LR at the muzzle. That means it lost around maybe 700-800 fps. That's a lot. But the 22 LR Velocitor only lost 320 fps at 100 yards. Stinger lost 525 fps.

[Outer Rondacker]

325 yards. That 45lc is going to be aimed at the moon. HEHE This should be fun to see the results. Oh and I was also wondering if the crony was going to be protected some how.

[fecmech]

Should be very similar as the BC's are about the same although the 255 Le RF is slightly higher .

[mehavey]

BC: 22 cal 44gr LRN = 0.1
BC: 45 cal 250 Keith = 0.2

No rocket science needed beyond that.

[shortlegs]

What brand of ( ( new chrony are u gona replace the shot one with? ( i have replaced 2)

[wills]

There are several online ballistics calculators you can use. This one appears simple. Easier than blowing up chronographs.

http://www.bergerbullets.com/ballistics/

[LazyTCross]

Messy bear will have a steel plate in front of his crony. It’s been used befor to figure out BCs on various projectiles. Lots of folks seem sure on this one. I will be waiting on the edge of my seat!!

[LazyTCross]

I’d give it about half of the front blade and let her fly with the 45

[tomme boy]

Pretty extreme oversimplification and not remotely true when discussing apples and oranges.

Must be new to shooting and have never shot long range have you?

[Neverhome]

Must be new to shooting and have never shot long range have you?

This is adorable.

Is the BC of a heavier bullet of whatever caliber ALWAYS higher than a lighter bullet of whatever caliber?
NO!

Yes weight obviously does factor in but to say in EVERY situation a heavier bullet will slow down less is as I said an oversimplification.
Disagree? Then go long with a wadcutter and see how fast it slows down

[JimB..]

I am very new to this, with most of my experience being pistols under 25yards. That said, I think that ballistic coefficient is based on measured values? And, it therefore incorporates all things like bullet mass, shape, material, and even time/distance to settle.

Online calculators extrapolate between known data points?

One question I do have is does the chronograph distinguish between vertical and horizontal velocity? If not, for a bullet with a rainbow trajectory do you attempt to accommodate gravitational acceleration and increase distance, or do that just go into the soup?

[Tom Myers]

Perhaps a clarification of the terms used for the elements that define a bullet's ballistic coefficient would be of some value here.

1.) The primary element that determines a Ballistic Coefficient is determined by the bullet profile or Form Factor (Coefficient of Form).
The form factor can be influenced by several profile features such as Meplate diameter and shape (flat, round), Front Driving Band Diameter, Boat Tail profile, or lack
of, and, in the case of Cast Bullets with turbulence causing grease grooves, Bearing Length.


2.) The secondary element used in calculating a Ballistic Coefficient is the Bullet's Sectional Density. And, it is what it is.
Sectional Density is simply, the bullet weight in pounds divided by the square of the bullet diameter, in inches.
Sectional Density = grain weight / 7000 / dia. / dia.

A Ballistic coefficient is calculated by dividing the Sectional Density by the Form Factor.

So, in the simplest terms, a heavier bullet with the same nose profile will have a higher calculated BC than a lighter bullet with the same nose profile.

So, when we make statements comparing bullet performance, unless a comparison of the bullet profiles is included within that statement, we are indeed, comparing apples to oranges.


For those interested in the algorithms and calculations used in the the Precision G1 Ballistic Coefficient Estimator (http://www.tmtpages.com/New_G1BC/cast_bc.htm), below are links to:

G1 Ballistic Coefficient Estimator Help Contents (http://www.tmtpages.com/New_G1BC/Help/G1_BC_Help.html)

Specific help file pages:

The Ogive Radius (http://www.tmtpages.com/New_G1BC/Help/hs190.htm)

The Form Factor (http://www.tmtpages.com/New_G1BC/Help/hs220.htm)

The Sectional Density (http://www.tmtpages.com/New_G1BC/Help/hs200.htm)

The Ballistic Coefficient (http://www.tmtpages.com/New_G1BC/Help/hs230.htm)

Hope this helps.

[Tom Myers]

One question I do have is does the chronograph distinguish between vertical and horizontal velocity? If not, for a bullet with a rainbow trajectory do you attempt to accommodate gravitational acceleration and increase distance, or do that just go into the soup?

Jim,

For bullets with a fairly flat trajectory, the gravitational deceleration and subsequent acceleration has almost no discernible effect on the trajectory calculations.

When calculating "rainbow trajectories" the horizontal retardation, the gravitational deceleration in the beginning portion of the trajectory and the gravitational acceleration in the remaining portion of the trajectory are velocity vectors that are considered in the trajectory calculations.

Most common, small arms, ballistic trajectory calculators use the "Flat Fire" algorithms in their calculations.

Accurate, trajectory calculations, whether long or short ranges, where the angle of departure is significantly higher than small arms trajectories must utilize the vertical and horizontal velocity vectors to calculate accurate trajectory values.

Years ago, when I first got into trajectory calculations, I wrote some code that utilized a military artillery method of calculations that, in addition to the vertical and horizontal velocity vectors, incorporated changes in air density as affected by altitude, barometric pressure, humidity and temperature into the trajectory calculations.

The best practical use I found for the program was to use it in calculating the trajectory of my hunting arrows. Once a ballistic coefficient for a particular type of arrow was determined, extremely accurate trajectory calculations for long range shots could be made using that program. Whereas, use of the flat fire method, would require constant ballistic coefficient changes at different ranges.

I also used the program to determine the maximum range and optimum angle of departure at a given muzzle velocity for various bullets from my firearms. I gained a new respect for knowing what existed down range from my firing point.

Another use was to determine the maximum altitude a bullet would attain and the maximum velocity it would reach when falling back to earth.
Needless to say, the data obtained was a real eye opener.
Sadly, none of my computers will now run the those old programs that were written in the original Pascal compilers.

[mdi]

I don't see any harm or anything odd about just wanting to know from experimental testing and validation. If one never does any hands on experimenting, just reading some one else's test reports, what fun is that?

[JimB..]

Perhaps a clarification of the terms used for the elements that define a bullet's ballistic coefficient would be of some value here.

1.) The primary element that determines a Ballistic Coefficient is determined by the bullet profile or Form Factor (Coefficient of Form).
The form factor can be influenced by several profile features such as Meplate diameter and shape (flat, round), Front Driving Band Diameter, Boat Tail profile, or lack
of, and, in the case of Cast Bullets with turbulence causing grease grooves, Bearing Length.


2.) The secondary element used in calculating a Ballistic Coefficient is the Bullet's Sectional Density. And, it is what it is.
Sectional Density is simply, the bullet weight in pounds divided by the square of the bullet diameter, in inches.
Sectional Density = grain weight / 7000 / dia. / dia.

A Ballistic coefficient is calculated by dividing the Sectional Density by the Form Factor.

So, in the simplest terms, a heavier bullet with the same nose profile will have a higher calculated BC than a lighter bullet with the same nose profile.

So, when we make statements comparing bullet performance, unless a comparison of the bullet profiles is included within that statement, we are indeed, comparing apples to oranges.


For those interested in the algorithms and calculations used in the the Precision G1 Ballistic Coefficient Estimator (http://www.tmtpages.com/New_G1BC/cast_bc.htm), below are links to:

G1 Ballistic Coefficient Estimator Help Contents (http://www.tmtpages.com/New_G1BC/Help/G1_BC_Help.html)

Specific help file pages:

The Ogive Radius (http://www.tmtpages.com/New_G1BC/Help/hs190.htm)

The Form Factor (http://www.tmtpages.com/New_G1BC/Help/hs220.htm)

The Sectional Density (http://www.tmtpages.com/New_G1BC/Help/hs200.htm)

The Ballistic Coefficient (http://www.tmtpages.com/New_G1BC/Help/hs230.htm)

Hope this helps.

Thank you for your comments, and also in the other post. Your comments did not however clarify for me if ballistic coefficient is really determined experimentally and then the impact of the various factors estimated through analysis, or if it is rather calculated and any real world deviance attributed to other factors. Specifically you say that ballistic coefficient is the sectional density divided by the coefficient of form...and I understand that the sectional density can be calculated, but how is the coefficient of form determined?

[Larry Gibson]

Actually the BC is derived from a comparison of the TOF (Time Of Flights velocity retardation rate; computed or measured) of the bullet to the TOF retardation of the "standard projectile" (most often the "G1") by division. Most BCs we find these days are based on computer models used in a computer program. Those often times, if not most of the time, are higher than actual measured BCs based on actual TOF.

I will find it interesting to see what the OP's radar actually measures the BCs at. I also measure BCs via the M43 Oehler by measuring the actual TOF of the bullets across 100 yards. Just two days ago I shot the 30 XCB bullet at 2900 fps out at 600 yards. Using the actual measured BC the Applied Ballistics program's elevation from a 100 to 600 yard zero was spot on. Using the computer generated BC in that program the elevation would have not have been correct. I agree the OP's experiment should prove interesting and informative.

[LazyTCross]

I think that it is quite interesting to compare the apples and oranges. Look at the conversation that it has started.
Powder, load and platform shouldn’t change the result of the stated goal. Speed will be measured at both ends.
Still looking forward to results

[reddog81]

I want to know how the chorno's were setup. At 325 yards you're going to have about 10 to 20 feet of drop and at least a couple feet of wind drift to deal with.

Why 325 yards? Wouldn't the BC calculations from 50 or 100 yards yield the same results.

[LazyTCross]

I am not sure why that range. I do know the messy bear commonly shoots at a steel ram outside his front door that is about that distance. I would assume one crony at 10-12 feet. As is typically how he sets things up. And the second one sits behind a steel plate with a hole cut into it.
I do know from looking at the plate that it has proven to be necessary. Not “every”shot at that range might make the 10” hole

[outdoorfan]

I see a few of us (in general) here have a hard time with someone experimenting like this. Who cares if it's been done before, even a million times. Who cares. I'll sit back and "eat my popcorn" and appreciate the time, effort, and risk it took someone else to gather data like this. No need to belittle. Fun!!

[LazyTCross]

Dang right!
This should rank right up there with our chronographing revolvers with no barrel test! Pointless, but dang fun and interesting!

[outdoorfan]

JBinMN,

No problem! Cheers!! :-P:drinks:

[tobywan45]

Dang right!
This should rank right up there with our chronographing revolvers with no barrel test! Pointless, but dang fun and interesting!And this is why I am following. Fun and interesting [emoji16]

Sent from my XT1585 using Tapatalk

[country gent]

BCs also change in velocity ranges. Mass of a projectile carries energy and velocity, Also sub sonic and super sonic affect velocity loss differently. Heres a good comparison to look at 308 762 nato in most loads 168 grn bt at 2650-2700 fps top range is around 1200yds a 50 bmg 700 grn bt at 2600 fps range is out to almost 3000 yds. These are 2 bullets close in form and velocity with the major difference being weight.

[wills]

If you think you need an excuse to get out and so some shooting, its as good a reason as any. Or if you are just after iformation you can read about it.

https://en.wikipedia.org/wiki/Ballistic_coefficient

http://www.sellier-bellot.cz/en/product/rifle-ammunition/ballistic-coefficient-calculation/

[Tom Myers]

Thank you for your comments, and also in the other post. Your comments did not however clarify for me if ballistic coefficient is really determined experimentally and then the impact of the various factors estimated through analysis, or if it is rather calculated and any real world deviance attributed to other factors. Specifically you say that ballistic coefficient is the sectional density divided by the coefficient of form...and I understand that the sectional density can be calculated, but how is the coefficient of form determined?

Jim,

Yes, the Coefficient of Form for the G[1, 2, 5, 6, 8 & L] and Krupp drag tables can be calculated.
The Coefficient of Form for the G7 series is best determined by measuring real world performance data. However the G7 Form Factor can be approximated by calculating a G1 factor and then dividing that value by 2. (The G7 is based on a standardized boat tail bullet with a 10 caliber secant ogive and a diameter of 0.50" whereas the G series is base on a projectile with a 1.00" diameter.)

As described in the link to the Form Factor (http://www.tmtpages.com/New_G1BC/Help/hs220.htm) in my previous post, the Coefficient of Form, or Form Factor (for the G? series of drag tables) may be calculated for pointed, jacketed bullets, with a tangent ogive nose profile, using a function of the ogive radius expressed in calibers.

*****
The basic function used to calculate the Coefficient of Form:
R = the radius of a tangential ogive divided by the diameter of the ogive base.

Form Factor = 2 / R * Square root of [ ( 4 * R - 1 ) / 7 ]

Proportional form factor modifications are required for any variation in meplate diameter.


*****
The radius of a tangential ogive can easily be calculated as described in the link to the Ogive Radius (http://www.tmtpages.com/New_G1BC/Help/hs190.htm)

*******
The function used to calculate the length of a tangential ogive radius.
NL = length of the curved portion of the nose.
D = The diameter of the nose where the curved portion begins.
T = The diameter of the tip or meplate, whether rounded or flat.
L = The length, in inches, of the curve radius.

L = ( NL * NL ) / ( D - T ) + ( D - T ) /4

*******


As also described in the link to the Form Factor (http://www.tmtpages.com/New_G1BC/Help/hs220.htm), using a highly modified form of the function used for pointed, jacketed bullets, the Form Factor for cast bullets with meplate values that are less than 50% of nose diameter, the Coefficient of Form may be reasonably estimated.
However, when calculating trajectory values for bullets with wide meplates [+ 50%], simply using the Sectional Density Value in place of the Ballistic Coefficient value will usually return a more realistic approximation of the trajectory.

As has been stated many times in this thread. A reliable ballistic coefficient value must be physically determined using actual trajectory values and,
as the title " G1 Ballistic Coefficient Estimator (http://www.tmtpages.com/New_G1BC/cast_bc.htm) " implys, if trajectory values are not available or can not be determined, they can be closely estimated and used for comparison purposes when calculating the external and terminal ballistics values for a particular bullet design.

Hope this helps.

[JimB..]

Jim,

Yes, the Coefficient of Form for the G[1, 2, 5, 6, 8 & L] and Krupp drag tables can be calculated.
The Coefficient of Form for the G7 series is best determined by measuring real world performance data. However the G7 Form Factor can be approximated by calculating a G1 factor and then dividing that value by 2. (The G7 is based on a standardized boat tail bullet with a 10 caliber secant ogive and a diameter of 0.50" whereas the G series is base on a projectile with a 1.00" diameter.)

As described in the link to the Form Factor (http://www.tmtpages.com/New_G1BC/Help/hs220.htm) in my previous post, the Coefficient of Form, or Form Factor (for the G? series of drag tables) may be calculated for pointed, jacketed bullets, with a tangent ogive nose profile, using a function of the ogive radius expressed in calibers.

*****
The basic function used to calculate the Coefficient of Form:
R = the radius of a tangential ogive divided by the diameter of the ogive base.

Form Factor = 2 / R * Square root of [ ( 4 * R - 1 ) / 7 ]

Proportional form factor modifications are required for any variation in meplate diameter.


*****
The radius of a tangential ogive can easily be calculated as described in the link to the Ogive Radius (http://www.tmtpages.com/New_G1BC/Help/hs190.htm)

*******
The function used to calculate the length of a tangential ogive radius.
NL = length of the curved portion of the nose.
D = The diameter of the nose where the curved portion begins.
T = The diameter of the tip or meplate, whether rounded or flat.
L = The length, in inches, of the curve radius.

L = ( NL * NL ) / ( D - T ) + ( D - T ) /4

*******


As also described in the link to the Form Factor (http://www.tmtpages.com/New_G1BC/Help/hs220.htm), using a highly modified form of the function used for pointed, jacketed bullets, the Form Factor for cast bullets with meplate values that are less than 50% of nose diameter, the Coefficient of Form may be reasonably estimated.
However, when calculating trajectory values for bullets with wide meplates [+ 50%], simply using the Sectional Density Value in place of the Ballistic Coefficient value will usually return a more realistic approximation of the trajectory.

As has been stated many times in this thread. A reliable ballistic coefficient value must be physically determined using actual trajectory values and,
as the title " G1 Ballistic Coefficient Estimator (http://www.tmtpages.com/New_G1BC/cast_bc.htm) " implys, if trajectory values are not available or can not be determined, they can be closely estimated and used for comparison purposes when calculating the external and terminal ballistics values for a particular bullet design.

Hope this helps.

It does, thank you very much!

[LazyTCross]

What’s the deal messy bear!? We are all hanging here waiting!

[Messy bear]

Dang! Had it typed out and timed out! Sorry guys been busy lately.

22- 1176 ave of 5 start velocity. Those 5 at 325 yd - 740 ave.

45- 1170 ave of 5 start velocity. Those 5 at 325 yd- 836 ave.

Messy

[Tom Myers]

Dang! Had it typed out and timed out! Sorry guys been busy lately.

22- 1176 ave of 5 start velocity. Those 5 at 325 yd - 740 ave.

45- 1170 ave of 5 start velocity. Those 5 at 325 yd- 836 ave.

Messy

Yeah!
It is what it is.

http://www.tmtpages.com/LinkSkyImages/forum_images/22-45%20BC/22-325ydBC.JPG

http://www.tmtpages.com/LinkSkyImages/forum_images/22-45%20BC/22-325ydTraj.JPG


http://www.tmtpages.com/LinkSkyImages/forum_images/22-45%20BC/45-325ydBCJPG.JPG

http://www.tmtpages.com/LinkSkyImages/forum_images/22-45%20BC/45-325ydTraj.JPG

[LazyTCross]

Great post Tom. Very cool

[Messy bear]

Thanks Tom! Yery interesting! I wonder what Lee says the b.c. is on that bullet?

[Tom Myers]

Thanks Tom! Yery interesting! I wonder what Lee says the b.c. is on that bullet?

Messy bear,

Lee Lists that Bullet as having a Ballistic Coefficient of 0.210

I acquired that mold some time ago to use in my 45 Long Colt revolver but never got around to trying it. Gonna have to do that this summer.
The only thing I have used it for is to make up a bunch of soft slugs fire-lap my Pedersoli Sharps 45-70. They worked great for that. No more leading.

Your test firing returns a B.C. of 0.1918.

My Cast Bullet Design and Evaluation software (http://www.tmtpages.com/#advanced) estimates a B.C. of 0.1798.

That suggests, to me, that this bullet, with your load, in your firearm is very stable throughout the trajectory.

Good work!

http://www.tmtpages.com/LinkSkyImages/forum_images/22-45%20BC/Lee-452-255-RF-Sketch.JPG

[Messy bear]

Tom
It was interesting that the extreme spread at muzzle on the shots that read down range was higher than the e.s. at 325yd. For example the 22's e.s. at muzzle was 33. At 325 it was 30.
The 45 was 20 at muzzle and ONLY 2 at 325! Crazy! Thanks for your input!

[Messy bear]

Duplicate deleted

[Mr_Sheesh]

Tom - Borland has a free Pascal compiler out there still, iirc. Or you can get someone to port that Pascal to C, if you want to. If you understand Pascal well, C isn't that big a step up; If you were a FORTRAN user and didn't learn Pascal first, though, C is a BIG step upwards. You probably know this all, just helping others understand :) I am interested in the subject, I almost always carry a DOS Palmtop (HP200LX family, 80c186) if not the far faster IBM PC110 (80486sx) - If you're into Linux IIRC there's a Pascal compiler for it out there too. C is more portable nowadays as they consider Pascal "obsolete", I've been using it since Borland came out with Turbo Pascal 1.0 for CP/M in 1977 or so :) (It beat the heck out of JRT Pascal, which was HORRID, slow, obnoxious, and inconsistent. One of the $50 software purchases that I still consider a good bargain!)