This section contains brief discussions of various ballistics and shooting related topics as requested by correspondents. If you have a question you have been trying to find an answer to (keep 'em ballistics and shooting related--see your minister for the mysteries of life) email me by clicking here and I'll do my best to find the answer for you and if it is of general interest, publish it here. If you can contribute additional input to one of the answers I'd would appreciate hearing from you too.
Check back frequently as new topics are always being added.
On this page:
What brand of magazines do you recommend
Is there an easy way to photograph cartridges?
What affect does a cannelure have on the ballistic coefficient of a bullet?
How do you determine the overall length to use for hollow point autopistol ammunition if you don't have factory data?
Is there any way to give brass different colors?
How fast is the speed of sound (Mach)?
All the advertisements and gun writers claim that the "short magnums" like the .300 WSM give the same ballistics but have less recoil that the "standard" magnums like the .300 Win Mag. Is this true.
Q. What brand of magazines do you recommend for autopistols?
A. That's another one of those questions that blood is frequently spilled over. There are many excellent brands out there and everyone has their favorite brand. However, you pretty much get what you pay for. I personally like the Tripp "Cobra Mags" for the 1911, but Wilson, ShootingStar, and Metalform mags are also liked by many people, and Megar makes the original equipment magazines for many manufacturers.
The important thing is to test them in YOUR pistol before relying on them as due to tolerance stacking some brands may work better in your pistol than others.
A couple of tips.
Whenever I buy magazines I always load them to full capacity and let them sit for a week or two to let the springs take whatever set they might get and then unload and inspect each magazine for digs, dents, and sharp edges that may have sneaked past quality control. I then fire 50 rounds out of each magazine before relying on them.
Don't forget to clean your magazines on a regular basis and check them for damage and cracks. If you use magazines with all-polymer followers be sure to inspect the slide stop shelf for wear and burring on a regular basis.
If a magazine does not function well one thing you can do is to use them as training magazines. Distinctively mark it (with say, a colored base pad) and use it to practice malfunction drills
With proper care magazines can last a long time as can their springs. Back in 1982 I was given 3 1911 GI magazines loaded with ball ammo dated 1918 that were found in some personal effects of a person who had died. The magazines had obviously seen heavy use and had been left loaded since the end of WW I. They functioned perfectly then (as did the ammo) and they still function fine today.
Q. Is there an easy way to photograph cartridges?
A. The method that I've used for years is very simple and doesn't require any special lighting. All you need is a camera (regular or digital) that will focus closely (down to 6" or less), a tripod, a piece of wood about 3/4" thick and a sheet or two of bright white paper (I use 24 pound "104 brightness" inkjet paper). I use any convenient diffused overhead lighting such as found in any room with overhead fluorescent lighting, or even outdoor on an overcast day, to minimize shadows. If you are using a digital camera that has a "white balance" function you can use it to ensure that the background shows as white and is not colored by the lighting. Keep the vertical backdrop fairly close to the subject (2 to 4 inches) or your background may appear darker than you want.
The pictures below are probably self explanatory but the white paper draped over a board gives a no-edge background that is raised up enough that the camera on the tripod can point straight in. Don't try to hand hold the camera! Use a tripod! I hold the paper to the board with a strip of double-sided tape and prop the back up with some books or a small box
With digital pictures you can use a paint program to crop and adjust your image to your liking. I find that giving the image one notch of sharpness enhancement makes the picture a bit crisper looking. Speaking of digital cameras, one doesn't need a high megapixel spec'd camera if you are taking pictures for a web site. A 2 MP model will do just fine--the important things are close focusing and adjustable white balance (which you can omit if you are careful about your lighting. Just get in close and fill the frame with your subject.
Cartridge picture taken
with a Nikon CoolPix 950 2 MP camera set to "fine" (1600 x
For superior results use an off-camera flash held above the camera location and angled down towards the items and set your camera to use "aperture priority" and a small f-stop say about f16, to get good depth of field.
By the way, if you use a digital camera you owe it to yourself to check out Ken Rockwell's site www.kenrockwell.com. While primarily dedicated to users of Nikon and Canon digital SLRs it is chock full of useful photographic knowledge.
Q. What affect does a cannelure have on the ballistic coefficient of a bullet?
A. The effect is quite small and varies with the shape and depth of the cannelure and seems to vary between about 3 and 12 percent. The table below shows the difference between several bullets that are identical except for a cannelure.
|140 gr .264 boattail||.550||.520|
|162 gr .280 boattail||.625||.570|
|168 gr .308 boattail||.475||.447|
What is the actual effect way out there. No very much unless you are talking about 1000 yards. At 500 yards the difference in drop amounts to less than 2" and at 1000 yards to about 10" assuming everything else stays the same.
Q. How do you determine the overall length to use for hollow point autopistol ammunition if you don't have factory data?
A. The overall length must be such that the cartridge will feed smoothly and still fit in the magazine. The method I have successfully used for .45 ACP ammunition is as follows. The critical setup seems to be having the bullet seated to the depth that the nose of the hollow point bullet falls within the profile of a properly seated FMJ RN bullet. I have a special seating stem cut to match the profile of the GI 230 gr FMJ RN bullet, set in a spare seating die. I set the test seater up to properly register on a GI ball round and then use that setting to seat the HP bullet in question and then measure the overall length. So far feeding has been perfect for all the bullets tried. The illustration below shows what is trying to be accomplished. You can probably adapt this method to other calibers that come with FMJ ammunition.
Q. Is there any way to give brass different colors?
A. The following information was published on rec.guns on 17 March 1995, by Royce W. Beal. It is reproduce here in full with permission.
Read this entire essay before attempting any one treatment. If you choose to just "cut and paste" part of this, please make sure you get the safety instructions and warnings after the recipes. Under no circumstances do I consider myself liable for any accidents which occur while using any of these chemicals. Also, I do not consider myself an expert in this field and am still doing research for the FAQ. This will be a temporary article. Because I am still experimenting, I cannot vouch for all of these colors.
Concentrations and conditions DO matter. (Concentration is more important than actual volume, so if you want to use less, make sure that you use proportionately less of each ingredient.) If you want good results follow the recipes closely. Above all it is important that the brass surfaces be clean. This means an extra hour or so in the tumbler for the cases and then touch them only sparingly.
I have tried to collate recipes which will require the acquisition of the more common chemicals. I have also tried to steer clear of the really hazardous arsenic and cyanide salts (which you probably can't get anyway). If you feel that you've been cheated by this, please refer to the references section of this report and find the books for yourself in any well stocked library.
It is my understanding that these are all surface coatings and should not damage or weaken the brass. Obviously you will want to do this treatment with unprimed brass. DO NOT USE METAL UTENSILS (ok maybe stainless steel), glass or plastic containers are the preference. If you are really worried about what this is going to do to your brass, refer again to the reference section below.
Copper Sulfate 8 ounces Ammonium Chloride 4 ounces Sodium Chloride 4 ounces Zinc Chloride 1 ounce Acetic Acid. 2 ounces Water 1 gallon
Copper Nitrate 4 ounces Acetic Acid 1 quart Water 1 gallon
Iron ( ferric) Nitrate * 2 ounces Sodium Hyposulphite 8 ounces Water 1 gallon
Use at boiling temperature, brass can be immersed or the solution may be "painted" on.
Iron (ferric) Nitrate 1 ounce Sodium Thiosulfate 6 ounces Water 1 gallon
Use at 160F
Iron (ferric) Nitrate 6 ounces Sodium hyposulphite 6 ounces Water 1 gallon
Using at 170F will speed up this reaction.
Sodium Hyposulphite 8 ounces Lead Acetate 4 ounces Water 1 gallon
Use at boiling temperature.
Lead Acetate 2 to 4 ounces Sodium Thiosulfate 8 ounces Acetic Acid 4 ounces Water 1 gallon
Use at 180F. This color will change if not lacquered [DO NOT LACQUER FIREARM CARTRIDGES] Take your chances with the color change.
Copper Carbonate 1 pound Ammonium Hydroxide 1 quart Water 3 quarts
Add the water after the carbonate and hydroxide have been mixed. There must be excess Copper Carbonate. Use at 175F. This color can be fixed (made more permanent) by quickly dipping in a 2.5% Sodium Hydroxide solution.
Ammonium Hydrosulfide 2.25 ounces Potassium sulfide 1 ounce Water 1 gallon
Use at room temperature or COOLER for best results.
Potassium Chlorate 5.5 ounces Nickel Sulfate 2.75 ounces Copper Sulfate 24 ounces Water 1 gallon
Use at boiling temperature.
CONVERSIONS AND INTERPRETATIONS
Ounces are assumably troy ounces, even when dealing with liquids or solutions. Do not use fluid ounces.
1 ounce = 31.103 grams = 480 grains
1 quart = 0.25 gallon = 946.4 mL
1 gallon = 3.785 L
Meyer, Walter R., Plating and Finishing Guidebook,
ninth edition - 1940 pp.72-75 (cited)
Metal Finishing Guidebook twenty-eighth edition - 1960, article by Hall, Nathaniel title Coloring of Metals pp. 477-479, (cited)
Krause, Hugo, Metal Coloring and Finishing (not cited)
Hiorns, A. H, Metal Coloring (not cited)
Field, S and Bonney, S.R., Chemical Coloring of Metals (not cited)
Additional formulas can be found at http://www.sciencecompany.com/patinas/patinaformulas.htm
Q. How fast is the speed of sound (Mach)?
A: The speed of sound in air is variously given as 1070 to 1120 f/s and the exact answer depends on temperature and altitude. In denser mediums the speed of sound increases as you can see from the data below which give the speed of sound in various mediums.
|Medium||Temp (Deg C)||Velocity (f/s)|
|Solution of Common Salt||18c||5,132|
|Solution Chloride of calcium||23c||6,493|
|Medium||Velocity at 20
|Velocity at 100
|Velocity at 200
The following table lists the speed of sound in various woods.
As can be seen from the graphics below the change of Mach with altitude is not uniform.
In the graphic below the atmosphere is broken down into regions of decreasing temperature (blue), constant temperature (green), and increasing temperature (red). This behavior is further illustrated below for the Troposphere, Tropopause, Stratosphere, Stratopause, Mesosphere, Mesopause, and lower Thermosphere. Above the Thermosphere is the Exosphere, which is well into what is considered to be space.
The graphic below gives an idea of temperature variation with altitude.
Graphics courtesy of http://www.aerospaceweb.org/question/atmosphere/q0112.shtml.
Q. All the advertisements and gun writers claim that the "short magnums" like the .300 WSM give the same ballistics but have less recoil that the "standard" magnums like the .300 Win Mag. Is this true.
A. Well, er, ah, ummm, ah...... Mainly advertising hype. The laws of physics state that for every action there is an equal and opposite reaction. Let's look at the facts. The stated ballistics (24") for a 180 gr bullet are effectively 3000 f/s for both cartridges. Typical powder charges for the WSM run about 65 - 70 grs and for the Win Mag about 80-85 gr.
Assuming an 8 pound rifle, a typical powder charge, and running the numbers for recoil (click here for more information) we get
|Recoil Velocity (f/s)||Recoil Energy (ft/lb)|
|.300 WSM 180gr @ 3000, 70 gr powder||14.6||26.6|
|.300 Win Mag 180 gr @ 3000, 85 gr powder||15.3||29.3|
OK, the WSM computes as having lower recoil but by an almost unnoticeable amount (3 ft/lbs is about the recoil of a 55 gr .223 in an 8 pound rifle). The difference could easily be masked by stock design. But even an inconsequential amount makes good add copy--the old adage about preoccupation with inconsequential increments (PII) hold true here.
But there are some flies in that ointment. First of all all of the .300 WSMs that I have seen chronographed seldom meet the advertised velocity, running closer to 2925 than 3000 from a 24" barrel and some are lower than that. (SAAMI specs require the velocity to be +/- 90 f/s from the stated velocity in a test barrel so there is a lot of jiggle room.) Second, there are an awful lot of short barreled .300 WSMs out there. I recently saw one with a 20(!!!) inch barrel. The shorter barrels give about 30 f/s + less velocity per inch cut from 24" so a 20" .300 WSM is about like a Hornady .30-06 180 gr "Lite Mag" loading or the old .300 H&H. Such progress we have.
Second most WSM handloads give noticeably less maximum velocity than the equivalent "regular" magnums. Perusing some loading manuals showed numerous maximum WSM loads giving 100 to 150 f/s less velocity that equivalent "regular" magnum maximum loads so of course recoil will be less under those circumstances. Reducing the velocity to 2925 with a 180 gr bullet in the WSM drops the recoil energy and velocity to about 25.5 ft/lb and 14 f/s respectively.
Does this all really matter? Not as far as I am concerned. The modern American shooter has been conditioned to pretty much fear recoil and the copy writers play this to the hilt. Some folks are afraid of a .308 Win! Shooting from a bench (which is all some folks do) with bad technique will hurt with even non-magnum calibers. Under field conditions recoil simply is not a concern unless one is very slightly built or frail. Unless you are shooting something like a 45 caliber stopper or an ultra high velocity big bore like a .416 Rem mag, worry about your marksmanship and not recoil. Having fired a number of very powerful rifles over the years, the only ones whose recoil was really intolerable were the .378 (only 61 ft/lb but very "sharp") and .460 Weatherbys (99 ft/lb), the .600 Nitro (107 ft/lb) and .700 Nitro (115 ft/lb) Express rounds. (I will decline further shots with either Express round.)
One thing not frequently mentioned about the short magnums is the fact that they are very hard on barrels and have been known to erode the throat out in under 500 rounds.
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As far as I know all the information presented above is correct and I have attempted to ensure that it is. However, I am not responsible for any errors, omissions, or damages resulting from the use or misuse of this information, nor for you doing something stupid with it. (Don't you hate these disclaimers? So do I, but there are people out there who refuse to be responsible for their own actions and who will sue anybody to make a buck.)