Technical Question: Range

[Mebits]

Does anyone have a formula for estimating the effective (dangerous) range for .177 pellet?

I imagine it's just math. pellet weight, size, muzzle velocity ought to get you pretty close to an accurate measurement for when the pellet drops to 200 fps. I've just not been able to find it.

If I had to guess, I'd say that my BC shooting CM's at probably 875fps might have a dangerous range of 85 yds... After that, you can probably stand in front of the shot (with safety glasses) and not get hurt. That's just a guess, however.

M

[only1harry]

That is correct, 200-300fps from a .177 will not hurt you unless you get hit in the eye of course.. and you could only take out a sparrow probably.  Anything over 300fps (around 325-350fps) will puncture human skin (don't ask how I know, hehehe). 

There is a web site where you put in the muzzle velocity, pellet weight, and it tells you the velocity down range and the pellet drop, but I believe you have to input the ballistic coefficient of the pellet which actually varies between different guns, so it's only an estimate.  I have not visited that site in a long time and I can't find it in my bookmarks, but maybe someone else knows the one I am talking about. 

I can tell you with certainty that at 50yds the CM will be traveling very close to 450fps. That's just over 4fpe.  It takes 3fpe to puncture skin and even crack your skull.  So your estimate of 85yds and 200-250fps is pretty accurate, but it could still take someone's eye out.. To effectively take a squirrel or a small critter you would have to keep the shots to inside 40yds or 45 max. effectiveness.  Small birds 55-60yds.  The CM usually has a poor ballistic coefficient (or BC as we call it).  Other domed pellets fair better and retain more velocity and energy down range.

Take a look at the Diana 34 velocity tests at the link below.  You may even find another gun that is closer to your Big Cat's velocity to see how it shoots with different pellets up to 50yds, but the 34 is pretty close +/- 10-25fps.

[Progun]

Hey Mebits, I don't have a formula per se but you might look at the StraightShooters "Our Take" to compare various pellets on their chart which gives energy ratings up to 50 yds. Pellets which have a higher BC will carry that "effective/dangerous" range a lot farther than those pellets which have a lower BC. I promise you, you don't want to be standing in front of the shot at 85yds or even at 100 yds with a shot from your Big Cat with a Crossman Premier pellet. I'd consider them dangerous at Big Cat velocities out past 150 yds. ymmv.

[Mebits]

See, Progun, this is what I'm a bit concerned about. I know the BC's hot...hotter than I'd have expected, even after passing through a bird. Then again, the CM is heavier than CP and has rotten aerodynamics.

I'll keep researching. I may, next time I get out to my friends' farm, do the "cardboard test". I'll set up a (fairly large) piece of cardboard at 100 yds and shoot at it. If the pellet pierces it, I move back, if not I'll move up until it does.

Still any further input or links are appreciated, as are the replies above.

[Mebits]

&^^&! I just read the "Our Take" link.

The BC is not a high end gun nor barrel, but it is advertised to shoot lead at about 1000 fps. The Beeman RX2 is a high end gun and it shot light pellets a bit north of 1000 fps, and close to 1100 fps.

At 50 yards, the CM's evidently were still moving at 635 fps. That's 8fpe. OW!

The Beeman R9 is at 542fps and 6fpe at 50 yds with the CM.

The Diana 34 is at 436fps and 4 fpe at 50 yds with the CM.

My take is that if the BC shoots as well as advertised (doubtful but remotely possible), it's definitely not safe with anything at 50 yards and definitely not "safe" with a domed at 75yds.

But, I really don't know where "safe" (sub 250 fps) actually is with the CM. Still researching.

M

[famine]

I have no idea, but I'm curious to know as well. I know that i've shot a fence post at 160+ yards and just put small dents in it with my Crosman Storm XT with CPHP's. I can get pics if you guys would like or if you think it would help in determining velocity, but i'm sure at that yardage it wasn't even close to being dangerous. I just did it because my dad didn't think i could get out that far.

[only1harry]

Yes, Straightshooters was the link that I mentioned and never pasted.  I think the 34 is the closest to your gun or it's between R9 and 34 (the 34 they tested is a bit weak).  The 34 I think was ~845-850 with CM's and yours 875.  At 50yds it was 436 or 4fpe like you said, so yours is probably around 460fps or 4.2fpe.  But like others said, I wouldn't want to be shot at even 100yds, but better be shot with a CM, than a domed pellet  

I 'd have to shoot beyond my town's borders with my Condors to find their non-dangerous range, hehehe   There have been people that shot rabbits at 120yds w/Condor and it was complete pass-through.  Something like 28fpe still left in the pellet at that range, which is why I try to shoot them at critters on the ground from an elevated position, or when they are directly in front of a tree.

[Mebits]

Harry,

The loss of speed isn't linear over distance, is it? I would have to think that after 50 yds, the spin decreases and air turbulence would conspire to start the (fairly light) pellet tumbling, totally messing up the aerodynamics, especially on an HP pellet, no? I'm not debating so much as trying to figure it out with you.

Everybody studies the ballistics in the "normal shooting zone", but nobody looks close at the "accidental hitting zone" way out there.

I'm pretty sure I'm going to have to run the test described above.

I suspect that the loss of velocity from 75 yds to 100yds is profound. I'm not willing to gamble my or anyone else's body on it, however.

Oh, here's the link you referenced:

http://www.straightshooters.com/navagationpages/ourtakselections.html

[Mebits]

And btw, Harry, I am SOOOOO jealous of the Condor. Of course, I'd need several more places to shoot it, if I had one.

M

[only1harry]

No, you are correct it is not linear.  The pellet will lose a lot of energy from 75 to 100yds, especially with a low BC as the CM's.  They lose energy and velocity fast past a "point"..  
Tumbling will not necessarily occur at "low speeds".  Not if the pellet was designed properly.. maybe at 100-150fps, it might, but even then.  I used to shoot soda cans with my 1861 Shiloh Co2 pistol which started out at 450fps.  I used to shoot until the 12gr CO2 was almost empty and the pellets never tumbled.

Finally as far as one owning a Condor, it really isn't for everyone.  It's not as much as the "place to shoot it", but also what type of critters you got.  I have just under 1 acre and have only used it a few times at 40yds and beyond, and a couple of times at 50yds.  95% of my shots are usually inside 35yds, but I have a lot of mid-sized critters which need super accurate shot placements and a little more "horsepower".  Power was not really my main objective, as strange as that may sound (hehehe) when I got a Condor.  If my 350 .22 or a Magnum Springer could shoot as accurately at 30-40yds as a Condor, I would have used it for pretty much everything.  I have taken Groundhogs out to 40yds with the 350 but when I lost 1 because the shot was off a little, that was not acceptable to me.  Having a very accurate gun from 30 to 50yds as my goal.  For 20-30yds I have no problems using a Springer and I often do.  I took all the country rats last year with the 350, but I will think twice about using a Springer on a larger 8 to 25lb animal beyond 30yds.

[Mebits]

Harry, I wasn't thinking about speed so much as spin decreasing and TIME out of the barrel giving air turbulence a chance to start a pellet tumbling. I'm just reasoning this stuff out, in theory. I have no idea if it really works that way consistently.

M

[RWSshooter]

Did anyone mention "Chairgun 2"?  Maybe it would help Mebits find his answers...just my $.02

[Carl]

Yep, chairgun will help. It also has the BC's for a lot of popular pellets. All you need is your Muzzle Velocity. I play around in it all the time.

[daveshoot]

Another vote for Chairgun. Here is a link for the free download: http://www.hawkeoptics.com/us/chairgun/download.php

I have heard it said a minimum of 4 fpe is required for sqirrel. No data to support that, just a common saying on the web.

I would not believe a single advertising claim for any pellet gun's velocity. If you don't have a chrony, search up posts by guys with the same gun using similar lead pellets who do have chrony results, and that should put you in the ballpark.

Most of the "specs" on the rifle box (and the web sites) are either using PBA alloy ammo, or just putting the magic 1000+ number out there as a sales gimmick. These numbers can be off by 300 fps against real hunting weight lead.