Small game, external ballistics, and the 17HMR

[Orsetto Lavatore]

I use a 17HMR for most of my small game hunting. With the FMJ and controlled expansion ammunition now available, head shots are no longer necessary to avoid excessive meat damage.

I use my 17 for squirrels and crows as well as bunnies - that means shots into the trees. This got me curious about the external ballistics of the 17HMR - what if I miss and the bullet goes sailing off?

We have all read on rimfire packages that it is "dangerous up to 2 miles"... I was curious as to what it takes to trow a fly-weight pill a mile or more, and what kind of power it would be packing.

We have also all heard that a bullet strait up is harmless, because of the low terminal velocity on such light objects, but that a ballistic trajectory is very dangerous. Here are my findings in graphic form:

The ballistic coefficient on a 20gr 17 caliber V-max is .182 - very poor. Here are the actual numbers for the entire 1700yd flight (roughly 1 mile):

From these diagrams we can see that it takes very little elevation for the 17 pill to travel a mile... but that it drops sub-sonic at only 1/4 that distance, and carries with it single digit energy levels. At the end of the mile long ballistic flight, the 17HMR arrives with a paltry 7 foot pounds of energy, and the velocity of a Daisy Red Ryder (but with a MUCH more fragile projectile).

It takes a STARK increase in elevation (18*-20*) to increase the travel distance from 1 mile to 1.5 miles, with the bullet arriving with a minuscule 4 ft-lbs.

This is all well and good, but WHAT is my point?

Apparently, even when firing into a relatively short(60ft) tree from 50 yards, you are exceeding the angles calculated here (> 20*) and your 17 is landing with even LESS energy than above. The closer you get to the tree, or the taller the tree is, the lower that energy becomes still - until it reaches its terminal velocity at vertical of 25fps, yielding .03 foot pounds (yes, 3/100 of ONE foot pound).

I'm not trying to prove a point here, just share something I found interesting while researching. This data will NOT represent any other caliber or cartridge, and it is NOT a general guideline.

Personally, this has put my mind at ease. Even when popping crows out of their roost, I can rest assured that my projectile will land with less than 1/2 the force of a childs BB gun. Even in the statistically unlikely event someone or someones property were hit, injury or damage would not likely result. COMBINED with RULE 4 of gun safely (be sure of your target and beyond), I can note the direction of my fire, and pass up shots that would direct the projectile towards settled areas, and continue hunting safely and without incident.

 

[Hoosierbuck]

Thank you for putting the thought into what I never have and generating a sound conclusion.

 

[Water63]

Very interesting I shoot the 17 round alot for squirrels I try to have the tree as a backstop but based on this that might not be as important as I thought.
Thanks for sharing not that I am going to just shoot with no disreguard but it is a safer round than I first thouhjt.

 

[Orsetto Lavatore]

As long as the angle is 20* or more, and most tree shot should be, the bullet will land with very little force... but using the tree as a backstop is still a good idea.

 

[.356luger]

sheww thought this was going to be a 17 thrashing and i was about to be upset untill i read the whole thing now im happy again. I love mine and now the distance drop makes me even more confident that i wont be killing the neighbors dog that is through the woods and over the creek if there is some freak occurance.

 

[Sailor]

I dont shoot 17 but thanks for the info.

 

[hornadylnl]

What about 17 fireball?

 

[CountryBoy19]

It takes a whole lot less than 4 ft-lbs to put an eye out. I know that the odds of that are so slim that it likely won't ever matter, but how would you feel if it did happen and you were the one that pulled the trigger?

What about windows? It doesn't take much to break a window.

One Sunday afternoon when I was young, we were all sitting in the living room watching a movie. We heard a window on the front porch shatter. We went to investigate and found a .22 bullet lodged in the window frame. From the angle that it came down it came from a long way off as well (at least 3/4 of a mile, but likely more) and it still had the energy to shatter a window.

How would you feel if you broke somebody's window and they had to pay to replace it?

The odds of ever being discovered as the person that pulled the trigger are slim, so you could probably get away with it, but I wish that all firearms owners had the honor and integrity to make the right choices... consider your actions wisely, because even though they may not take a life, they can still change somebody's life forever.

 

[billyboyr6]

It takes a whole lot less than 4 ft-lbs to put an eye out. I know that the odds of that are so slim that it likely won't ever matter, but how would you feel if it did happen and you were the one that pulled the trigger?

What about windows? It doesn't take much to break a window.

One Sunday afternoon when I was young, we were all sitting in the living room watching a movie. We heard a window on the front porch shatter. We went to investigate and found a .22 bullet lodged in the window frame. From the angle that it came down it came from a long way off as well (at least 3/4 of a mile, but likely more) and it still had the energy to shatter a window.

How would you feel if you broke somebody's window and they had to pay to replace it?
The odds of ever being discovered as the person that pulled the trigger are
slim, so you could probably get away with it, but I wish that all firearms owners had the honor and integrity to make the right choices... consider your actions wisely, because even though they may not take a life, they can still change somebody's life forever.

This is true, but your talking 36-40 gr .22 lr
bullet. A 20 gr .17 bullet has half the weight and half the inertia ( I think that is how you spell it). .17 may not have had enough left on contact to put window out from same distance. Not saying anyone is right or wrong, just stating a valid point.

 

[willhirsch]

Great information, thanks for the post!

 

[shibumiseeker]

This is true, but your talking 36-40 gr .22 lr
bullet. A 20 gr .17 bullet has half the weight and half the inertia ( I think that is how you spell it). .17 may not have had enough left on contact to put window out from same distance. Not saying anyone is right or wrong, just stating a valid point.

Valid points to a degree, but you are still responsible for any bullet you launch. I consider angles and what is off behind where a bullet lands when I am hunting on my property. It's easy for me because if you draw a 1 mile radius from my place there are only like 5 houses and most of everything else is woods.

The .17hmr is better than a .22 in that regard. When I was hunting squirrel and rabbit on public lands before I got my place I was using a .410 just for that reason: I know the shot is going to be harmless very quickly.