I have a piece of property that I hunt on. 280 acres. the surrounding area is somewhat suburban. There are many places I can discharge a firearm using the 500 feet from residence rule/law. I have a Black Mouth Cur I use for squirrels and starting on coon. I want to shoot the squirrels but also want to be a little quiet about it, no sense in alarming the neighbors. I have a Crosman TR77 pellet gun. nice and quiet, 1000fps. I have a Ruger Single Six with a 4 5/8" barrel that I would prefer to use. I have some CCI quiet ammo which shoots out of a rifle at 710 fps.

The question I have is, I never worry if I miss the squirrel and tree when shooting up using the pellet gun. Just shoot up in the air and no fear that it will hurt human or damage property. Is there a difference shooting the .22 lr quiet? even with a lower velocity, will it travel farther? could it potentially land somewhere that it could do property damage or bodily harm?

I guess I am wondering if a .22 quiet round will travel farther at 710fps than a pellet at 1000fps.

That is gonna depend on the weight of each projectile.

That is something to ponder.

While you shoot squirrels.



Travis

It actually does not depend on weight of the projectile.

BC on the other hand...

Both are useful. Weight is easier to attain and will suffice for a basic comparison.

Acctualy is does depend on mass. Mass is extremely significant aspect of BC.

Since the .177 pellet and the .22 rimfire have a different diameter and shape the direct effect of mass doesn't matter.

It will which is why, when needed, my big critter pellet rifle is a .22 RWS M48. I have owned it for 20 years and have thumped an azzload of ground squirrels and rabbits with it out to 70 yards with the heavier Crosman Premier.

Yes, the .22 bullet will travel much farther than an airgun's pellet, which will shed its velocity much more quickly.

Thanks CraigC.

So... in your trajactory calculator, you're changing the mass of your projectile (for the same caliber) and finding that it changes your trajectory? You are also calculating your BC with the mass term explicitly entered for your projectile?

Lemme know - there must be something I don't understand.

Mass always matter, if not then we could make very long bullets from aluminum with extremely high BCs. The 177 pellet is low in mass for the diameter.

The direct effect of mass doesn't matter.

Case in point: Which bullet will fly the farthest at the same velocity, a 105 grain or a 168 grain?

As I said mass in relation to diameter such as A 105 grain 6mm VS a 168 7mm or 30?

http://www.jbmballistics.com/ballistics/topics/secdens.shtml


Sectional Density and Ballistic Coefficients

Sectional density equations and calculations. References and a list of variables are at the bottom of this page.

The BC, or ballistic coefficient is defined as:

BC = w / [i d2]
here the diameter is specified in inches and the weight in pounds and the form factor is found using:

i = CD / CDG
The sectional density is defined as:

SD = w / d2
making the ballistic coefficient

BC = SD / i
[NOTE: Some references define the sectional density with the mass not weight. All the listings I've seen from bullet manufacturers use weight. Most ballistics texts use mass.]

So this means that the ballistic coefficient is proportional to the weight of the bullet and inversely proportional to the diameter squared. (Keep in mind that the ballistic coefficient is also inversely proportional to the form factor which depends on the shape of the bullet!)

Calculation of the sectional density is straight forward. For a 300 grain, .338 caliber bullet, the sectional density is:

SD = [ 300 gr / (7000 gr/lb) ] / [ 0.338 in ]2 = 0.375 lb/in2
NOTE: With the common definition of the sectional density, the units have to be converted when used with drag functions, velocity, etc, to convert the in2 to ft2 resulting in a factor of 144.

Variables

d bullet diameter w bullet weight
SD sectional density BC ballistic coefficient
i form factor G "G" function
CD drag coefficient CDG drag coefficient of the standard bullet
References

Hatcher's Notebook, Julian S. Hatcher, Major General, USA, retired, Stackpole Books, Harrisburg, Pennsylvania, Second printing, 1966.

That's correct

Weight matters

Mass in relation to diameter is call sectional density.